Category: Linux

Seven Important Security Headers for Your Website

When it comes to securing your website, it’s all about minimizing attack surface and adding more layers of security. One strong layer that you can (and should) add is proper HTTP security headers. When responding to requests, your server should include security headers that help stop unwanted activity like XSS, MITM, and click-jacking attacks. While sending security headers does not guarantee 100% defense against all such attacks, it does help modern browsers keep things secure. So in this tutorial, we walk through seven of the most important and effective HTTP security headers to add a strong layer of security to your Apache-powered website.

Contents

Note: You can verify your site’s security headers using a free online tool such as the one provided by SecurityHeaders.com.

X-XSS-Protection

The X-XSS-Protection security header enables the XSS filter provided by modern web browsers (IE8+, Chrome, Firefox, Safari, et al). Here is the recommended configuration for this header:

# X-XSS-Protection
<IfModule mod_headers.c>
	Header set X-XSS-Protection "1; mode=block"
</IfModule>

Added to your site’s .htaccess file or server configuration file, this code instructs supportive browsers to block any requests containing malicious scripts. For more configuration options and further information about X-XSS-Protection, check out these resources:

X-Frame-Options

The X-Frame-Options (XFO) security header helps modern web browsers protect your visitors against clickjacking and other threats. Here is the recommended configuration for this header:

# X-Frame-Options
<IfModule mod_headers.c>
	Header set X-Frame-Options "SAMEORIGIN"
</IfModule>

Added to your site’s .htaccess file or server configuration file, this code instructs supportive browsers to block any frames/content requested from external locations. So if your own site includes an iframe that loads a resources from the same domain, the content will load normally. But if any iframe is included that loads resources from any other domain, the content will be blocked. For more configuration options and further information about X-Frame-Options, check out these resources:

X-Content-Type-Options

The X-Content-Type-Options security header enables supportive browsers to protect against MIME-type sniffing exploits. It does this by disabling the browser’s MIME sniffing feature, and forcing it to recognize the MIME type sent by the server. This header is very flexible and may be configured extensively, however the most common implementation looks like this:

# X-Content-Type-Options
<IfModule mod_headers.c>
	Header set X-Content-Type-Options "nosniff"
</IfModule>

Added to your site’s .htaccess file or server configuration file, this code instructs supportive browsers to use the MIME type declared by the origin server. There are a couple of precautions to keep in mind. First, as with any security header, it does not stop 100% of all attacks or threats; it does stop some of them, however, and thus provides another layer of protection for your site. Also note that this header currently is supported only in Chrome and later versions of Internet Explorer. Hopefully other browsers will add support in the future. For more configuration options and further information about X-Content-Type-Options, check out these resources:

Strict-Transport-Security

The Strict-Transport-Security (HSTS) header instructs modern browsers to always connect via HTTPS (secure connection via SSL/TLS), and never connect via insecure HTTP (non-SSL) protocol. While there are variations to how this header is configured, the most common implementation looks like this:

# Strict-Transport-Security
<IfModule mod_headers.c>
	Header always set Strict-Transport-Security "max-age=63072000; includeSubDomains"
</IfModule>

Added to your site’s .htaccess file or server configuration file, this code instructs supportive browsers to always use HTTPS for connections. This helps stop man-in-the-middle (MITM) and other attacks targeting insecure HTTP connections. For more configuration options and further information about Strict-Transport-Security, check out these resources:

Referrer-Policy

The Referrer-Policy security header instructs modern browsers how to handle or exclude the Referer header (yes the header normally is spelled incorrectly, missing an “r”). For those who may not be familiar, the Referer header contains information about where a request is coming from. So for example if you are at example.com and click a link from there to domain.tld, the Referer header would specify example.com as the “referring” URL.

With that in mind, the Referrer-Policy enables you to control whether or not the Referer header is included with the request. Here is an example showing how to add the Referrer-Policy header via Apache:

# Referrer-Policy
<IfModule mod_headers.c>
	Header set Referrer-Policy "same-origin"
</IfModule>

Added to your site’s .htaccess file or server configuration file, this code instructs supportive browsers to only set the referrer header for request from the current domain (same-origin). Keep in mind that this header is less about security and more about controlling referrer information, as is required by various rules and regulations (e.g., GDPR). For more configuration options and further information about Referrer-Policy, check out these resources:

Feature-Policy

The Feature-Policy header tells modern browsers which browser features are allowed. For example, if you want to ensure that only geolocation and vibrate features are allowed, you can configure the Feature-Policy header accordingly. It also enables you to control the origin for each specified feature. Here is an example showing how to add a Feature-Policy header via Apache:

# Feature-Policy
<IfModule mod_headers.c>
	Header set Feature-Policy "geolocation 'self'; vibrate 'none'"
</IfModule>

Added to your site’s .htaccess file or server configuration file, this code instructs supportive browsers to enable only geo-location and vibrate features. Keep in mind that this header is less about security and more about ensuring a smooth experience for your users. For more configuration options and further information about Feature-Policy, check out these resources:

Content-Security-Policy

The Content-Security-Policy (CSP) header tells modern browsers which dynamic resources are allowed to load. This header is especially helpful at stopping XSS attacks and other malicious activity. This header provides extensive configuration options, which will need to be fine-tuned to match the specific resources required by your site. Otherwise if the header configuration does not match your site’s requirements, some resources may not load (or work) properly.

Because of this, there isn’t one most common example to look at. So instead here are a few different examples, each allowing different types of resources.

Example 1

First example, here is a CSP directive that allows resources from a CDN, and disallows any framed content or media plugins. This example is from the Google docs page linked below.

# Content-Security-Policy - Example 1
<IfModule mod_headers.c>
	Header set Content-Security-Policy "default-src https://cdn.example.com; child-src 'none'; object-src 'none'"
</IfModule>

Example 2

Second example, this CSP directive enables script resources loaded from a jQuery subdomain, and limits stylesheets and images to the current domain (self). This example is from the Mozilla docs page linked below.

# Content-Security-Policy - Example 2
<IfModule mod_headers.c>
	Header set Content-Security-Policy "default-src 'none'; img-src 'self'; script-src 'self' https://code.jquery.com; style-src 'self'"
</IfModule>

Example 3

And for a third example, here is the directive I use on most of my WordPress-powered sites. Logically these sites tend to use the same types of resources, so I can keep things simple and use the following code on all sites:

# Content-Security-Policy - Example 3
<IfModule mod_headers.c>
	Header set Content-Security-Policy "default-src https:; font-src https: data:; img-src https: data:; script-src https:; style-src https:;"
</IfModule>

To get a better idea of what’s happening here, let’s apply a bit of formatting to the code:

Header set Content-Security-Policy "

default-src https:; 
font-src    https: data:; 
img-src     https: data:; 
script-src  https:; 
style-src   https:;

"

Stare at that for a few moments and you should get the idea: the header is setting the allowed source(s) for fonts, images, scripts, and styles. For each of these, a secure HTTPS connection is required. The only exception is also to allow data URIs as a source for fonts and images.

So for any of these examples, when added to your site’s .htaccess file or server configuration file, the code tells supportive browsers which dynamic resources are allowed and/or not allowed. But seriously, if you’re thinking about adding the powerful Content-Security-Policy security header, take a few moments to read thru some of the documentation:

Where to get help with CSP

Yes CSP can be confusing, but there is no reason to despair. There are numerous online tools that make it easier to figure out how to implement CSP, for example here are some top sites:

A quick search for “csp test online” yields many results.

Even better, they now have “CSP generators” that literally write the code for you based on your input variables. Here are two solid looking CSP generators:

There are lots of useful tools out there to make CSP easier. Just enter your infos and copy/paste the results. If in doubt, use multiple tools and compare the results; the code should be the same. If not, don’t hesitate to reach out to the tool providers, who will be able to answer any questions, etc.

All Together

For the sake of easy copy/pasting, here is a code snippet that combines all of the above-described security headers.

Important: before adding this code to your site, make sure to read through each technique as explained in corresponding sections above. There may be important notes and information that you need to understand regarding each particular directive included in this code snippet.

# Security Headers
<IfModule mod_headers.c>
	Header set X-XSS-Protection "1; mode=block"
	Header set X-Frame-Options "SAMEORIGIN"
	Header set X-Content-Type-Options "nosniff"
	Header always set Strict-Transport-Security "max-age=63072000; includeSubDomains"
	# Header set Content-Security-Policy ...
	Header set Referrer-Policy "same-origin"
	Header set Feature-Policy "geolocation 'self'; vibrate 'none'"
</IfModule>

As with each of the above techniques, this code may be added to your site via .htaccess or Apache config. Understand that this technique includes commonly used configurations for each of the included headers. You can (and should) go through each one to make sure that the configuration matches the requirements and goals of your site. Also remember to test thoroughly before going live.

Note: Notice the following line in the above “Security Headers” code snippet:

# Header set Content-Security-Policy ...

The pound sign or hash tag or whatever you want to call it means that the line is disabled and is ignored by the server. This means that the Content-Security-Policy directive is “commented out” and thus not active in this technique. Why? Because as explained previously, there is no recommended “one-size-fits-all” CSP example that works perfectly in all websites. Instead, you will need to replace the commented out line with your own properly configured CSP header, as explained above.

SSL and TLS Deployment Best Practices

Version 1.6-draft (15 January 2020)

SSL/TLS is a deceptively simple technology. It is easy to deploy, and it just works–except when it does not. The main problem is that encryption is not often easy to deploy correctly. To ensure that TLS provides the necessary security, system administrators and developers must put extra effort into properly configuring their servers and developing their applications.

In 2009, we began our work on SSL Labs because we wanted to understand how TLS was used and to remedy the lack of easy-to-use TLS tools and documentation. We have achieved some of our goals through our global surveys of TLS usage, as well as the online assessment tool, but the lack of documentation is still evident. This document is a step toward addressing that problem.

Our aim here is to provide clear and concise instructions to help overworked administrators and programmers spend the minimum time possible to deploy a secure site or web application. In pursuit of clarity, we sacrifice completeness, foregoing certain advanced topics. The focus is on advice that is practical and easy to follow. For those who want more information, Section 6 gives useful pointers.

1 Private Key and Certificate

In TLS, all security starts with the server’s cryptographic identity; a strong private key is needed to prevent attackers from carrying out impersonation attacks. Equally important is to have a valid and strong certificate, which grants the private key the right to represent a particular hostname. Without these two fundamental building blocks, nothing else can be secure.

1.1 Use 2048-Bit Private Keys

For most web sites, security provided by 2,048-bit RSA keys is sufficient. The RSA public key algorithm is widely supported, which makes keys of this type a safe default choice. At 2,048 bits, such keys provide about 112 bits of security. If you want more security than this, note that RSA keys don’t scale very well. To get 128 bits of security, you need 3,072-bit RSA keys, which are noticeably slower. ECDSA keys provide an alternative that offers better security and better performance. At 256 bits, ECDSA keys provide 128 bits of security. A small number of older clients don’t support ECDSA, but modern clients do. It’s possible to get the best of both worlds and deploy with RSA and ECDSA keys simultaneously if you don’t mind the overhead of managing such a setup.

1.2 Protect Private Keys

Treat your private keys as an important asset, restricting access to the smallest possible group of employees while still keeping your arrangements practical. Recommended policies include the following:

  • Generate private keys on a trusted computer with sufficient entropy. Some CAs offer to generate private keys for you; run away from them.
  • Password-protect keys from the start to prevent compromise when they are stored in backup systems. Private key passwords don’t help much in production because a knowledgeable attacker can always retrieve the keys from process memory. There are hardware devices (called Hardware Security Modules, or HSMs) that can protect private keys even in the case of server compromise, but they are expensive and thus justifiable only for organizations with strict security requirements.
  • After compromise, revoke old certificates and generate new keys.
  • Renew certificates yearly, and more often if you can automate the process. Most sites should assume that a compromised certificate will be impossible to revoke reliably; certificates with shorter lifespans are therefore more secure in practice.
  • Unless keeping the same keys is important for public key pinning, you should also generate new private keys whenever you’re getting a new certificate.

1.3 Ensure Sufficient Hostname Coverage

Ensure that your certificates cover all the names you wish to use with a site. Your goal is to avoid invalid certificate warnings, which confuse users and weaken their confidence.

Even when you expect to use only one domain name, remember that you cannot control how your users arrive at the site or how others link to it. In most cases, you should ensure that the certificate works with and without the www prefix (e.g., that it works for both example.com and www.example.com). The rule of thumb is that a secure web server should have a certificate that is valid for every DNS name configured to point to it.

Wildcard certificates have their uses, but avoid using them if it means exposing the underlying keys to a much larger group of people, and especially if doing so crosses team or department boundaries. In other words, the fewer people there are with access to the private keys, the better. Also be aware that certificate sharing creates a bond that can be abused to transfer vulnerabilities from one web site or server to all other sites and servers that use the same certificate (even when the underlying private keys are different).

Make sure you add all the necessary domain names to Subject Alternative Name (SAN) since all the latest browsers do not check for Common Name for validation

1.4 Obtain Certificates from a Reliable CA

Select a Certification Authority (CA) that is reliable and serious about its certificate business and security. Consider the following criteria when selecting your CA:

Security posture All CAs undergo regular audits, but some are more serious about security than others. Figuring out which ones are better in this respect is not easy, but one option is to examine their security history, and, more important, how they have reacted to compromises and if they have learned from their mistakes.

Business focus CAs whose activities constitute a substantial part of their business have everything to lose if something goes terribly wrong, and they probably won’t neglect their certificate division by chasing potentially more lucrative opportunities elsewhere.

Services offered At a minimum, your selected CA should provide support for both Certificate Revocation List (CRL) and Online Certificate Status Protocol (OCSP) revocation methods, with rock-solid network availability and performance. Many sites are happy with domain-validated certificates, but you also should consider if you’ll ever require Extended Validation (EV) certificates. In either case, you should have a choice of public key algorithm. Most web sites use RSA today, but ECDSA may become important in the future because of its performance advantages.

Certificate management options If you need a large number of certificates and operate in a complex environment, choose a CA that will give you good tools to manage them.

Support Choose a CA that will give you good support if and when you need it.

Note

For best results, acquire your certificates well in advance and at least one week before deploying them to production. This practice (1) helps avoid certificate warnings for some users who don’t have the correct time on their computers and (2) helps avoid failed revocation checks with CAs who need extra time to propagate new certificates as valid to their OCSP responders. Over time, try to extend this “warm-up” period to 1-3 months. Similarly, don’t wait until your certificates are about to expire to replace them. Leaving an extra several months there would similarly help with people whose clocks are incorrect in the other direction.

1.5 Use Strong Certificate Signature Algorithms

Certificate security depends (1) on the strength of the private key that was used to sign the certificate and (2) the strength of the hashing function used in the signature. Until recently, most certificates relied on the SHA1 hashing function, which is now considered insecure. As a result, we’re currently in transition to SHA256. As of January 2016, you shouldn’t be able to get a SHA1 certificate from a public CA. Leaf and intermediate certificates having SHA1 hashing signature are now considered insecure by browser.

1.6 Use DNS CAA

DNS CAA[8] is a standard that allows domain name owners to restrict which CAs can issue certificates for their domains. In September 2017, CA/Browser Forum mandated CAA support as part of its certificate issuance standard baseline requirements. With CAA in place, the attack surface for fraudulent certificates is reduced, effectively making sites more secure. If the CAs have automated process in place for issuance of certificates, then it should check for DNS CAA record as this would reduce the improper issuance of certificates.

It is recommended to whitelist a CA by adding a CAA record for your certificate. Add CA’s which you trust for issuing you a certificate.

2 Configuration

With correct TLS server configuration, you ensure that your credentials are properly presented to the site’s visitors, that only secure cryptographic primitives are used, and that all known weaknesses are mitigated.

2.1 Use Complete Certificate Chains

In most deployments, the server certificate alone is insufficient; two or more certificates are needed to build a complete chain of trust. A common configuration problem occurs when deploying a server with a valid certificate, but without all the necessary intermediate certificates. To avoid this situation, simply use all the certificates provided to you by your CA in the same sequence.

An invalid certificate chain effectively renders the server certificate invalid and results in browser warnings. In practice, this problem is sometimes difficult to diagnose because some browsers can reconstruct incomplete chains and some can’t. All browsers tend to cache and reuse intermediate certificates.

2.2 Use Secure Protocols

There are six protocols in the SSL/TLS family: SSL v2, SSL v3, TLS v1.0, TLS v1.1, TLS v1.2, and TLS v1.3:

  • SSL v2 is insecure and must not be used. This protocol version is so bad that it can be used to attack RSA keys and sites with the same name even if they are on an entirely different servers (the DROWN attack).
  • SSL v3 is insecure when used with HTTP (the SSLv3 POODLE attack) and weak when used with other protocols. It’s also obsolete and shouldn’t be used.
  • TLS v1.0 and TLS v1.1 are legacy protocol that shouldn’t be used, but it’s typically still necessary in practice. Its major weakness (BEAST) has been mitigated in modern browsers, but other problems remain. TLS v1.0 has been deprecated by PCI DSS. Similarly, TLS v1.0 and TLS v1.1 has been deprecated in January 2020 by modern browsers. Check the SSL Labs blog link
  • TLS v1.2 and v1.3 are both without known security issues.

TLS v1.2 or TLS v1.3 should be your main protocol because these version offers modern authenticated encryption (also known as AEAD). If you don’t support TLS v1.2 or TLS v1.3 today, your security is lacking.

In order to support older clients, you may need to continue to support TLS v1.0 and TLS v1.1 for now. However, you should plan to retire TLS v1.0 and TLS v1.1 in the near future. For example, the PCI DSS standard will require all sites that accept credit card payments to remove support for TLS v1.0 by June 2018. Similarly, modern browsers will remove the support for TLS v1.0 and TLS v1.1 by January 2020.

Benefits of using TLS v1.3:

  • Improved performance i.e improved latency
  • Improved security
  • Removed obsolete/insecure features like cipher suites, compression etc.

2.3 Use Secure Cipher Suites

To communicate securely, you must first ascertain that you are communicating directly with the desired party (and not through someone else who will eavesdrop) and exchanging data securely. In SSL and TLS, cipher suites define how secure communication takes place. They are composed from varying building blocks with the idea of achieving security through diversity. If one of the building blocks is found to be weak or insecure, you should be able to switch to another.

You should rely chiefly on the AEAD suites that provide strong authentication and key exchange, forward secrecy, and encryption of at least 128 bits. Some other, weaker suites may still be supported, provided they are negotiated only with older clients that don’t support anything better.

There are several obsolete cryptographic primitives that must be avoided:

  • Anonymous Diffie-Hellman (ADH) suites do not provide authentication.
  • NULL cipher suites provide no encryption.
  • Export cipher suites are insecure when negotiated in a connection, but they can also be used against a server that prefers stronger suites (the FREAK attack).
  • Suites with weak ciphers (112 bits or less) use encryption that can easily be broken are insecure.
  • RC4 is insecure.
  • 64-bit block cipher (3DES / DES / RC2 / IDEA) are weak.
  • Cipher suites with RSA key exchange are weak i.e. TLS_RSA

There are several cipher suites that must be preferred:

  • AEAD (Authenticated Encryption with Associated Data) cipher suites – CHACHA20_POLY1305, GCM and CCM
  • PFS (Perfect Forward Secrecy) ciphers – ECDHE_RSA, ECDHE_ECDSA, DHE_RSA, DHE_DSS, CECPQ1 and all TLS 1.3 ciphers

Use the following suite configuration, designed for both RSA and ECDSA keys, as your starting point:

TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
TLS_DHE_RSA_WITH_AES_128_GCM_SHA256
TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
TLS_DHE_RSA_WITH_AES_128_CBC_SHA
TLS_DHE_RSA_WITH_AES_256_CBC_SHA
TLS_DHE_RSA_WITH_AES_128_CBC_SHA256
TLS_DHE_RSA_WITH_AES_256_CBC_SHA256

Warning

We recommend that you always first test your TLS configuration in a staging environment, transferring the changes to the production environment only when certain that everything works as expected. Please note that the above is a generic list and that not all systems (especially the older ones) support all the suites. That’s why it’s important to test first.

The above example configuration uses standard TLS suite names. Some platforms use nonstandard names; please refer to the documentation for your platform for more details. For example, the following suite names would be used with OpenSSL:

ECDHE-ECDSA-AES128-GCM-SHA256
ECDHE-ECDSA-AES256-GCM-SHA384
ECDHE-ECDSA-AES128-SHA
ECDHE-ECDSA-AES256-SHA
ECDHE-ECDSA-AES128-SHA256
ECDHE-ECDSA-AES256-SHA384
ECDHE-RSA-AES128-GCM-SHA256
ECDHE-RSA-AES256-GCM-SHA384
ECDHE-RSA-AES128-SHA
ECDHE-RSA-AES256-SHA
ECDHE-RSA-AES128-SHA256
ECDHE-RSA-AES256-SHA384
DHE-RSA-AES128-GCM-SHA256
DHE-RSA-AES256-GCM-SHA384
DHE-RSA-AES128-SHA
DHE-RSA-AES256-SHA
DHE-RSA-AES128-SHA256
DHE-RSA-AES256-SHA256

2.4 Select Best Cipher Suites

In SSL v3 and later protocol versions, clients submit a list of cipher suites that they support, and servers choose one suite from the list to use for the connection. Not all servers do this well, however; some will select the first supported suite from the client’s list. Having servers actively select the best available cipher suite is critical for achieving the best security.

2.5 Use Forward Secrecy

Forward secrecy (sometimes also called perfect forward secrecy) is a protocol feature that enables secure conversations that are not dependent on the server’s private key. With cipher suites that do not provide forward secrecy, someone who can recover a server’s private key can decrypt all earlier recorded encrypted conversations. You need to support and prefer ECDHE suites in order to enable forward secrecy with modern web browsers. To support a wider range of clients, you should also use DHE suites as fallback after ECDHE. Avoid the RSA key exchange unless absolutely necessary. My proposed default configuration in Section 2.3 contains only suites that provide forward secrecy.

2.6 Use Strong Key Exchange

For the key exchange, public sites can typically choose between the classic ephemeral Diffie-Hellman key exchange (DHE) and its elliptic curve variant, ECDHE. There are other key exchange algorithms, but they’re generally insecure in one way or another. The RSA key exchange is still very popular, but it doesn’t provide forward secrecy.

In 2015, a group of researchers published new attacks against DHE; their work is known as the Logjam attack.[2] The researchers discovered that lower-strength DH key exchanges (e.g., 768 bits) can easily be broken and that some well-known 1,024-bit DH groups can be broken by state agencies. To be on the safe side, if deploying DHE, configure it with at least 2,048 bits of security. Some older clients (e.g., Java 6) might not support this level of strength. For performance reasons, most servers should prefer ECDHE, which is both stronger and faster. The secp256r1 named curve (also known as P-256) is a good choice in this case.

2.7 Mitigate Known Problems

There have been several serious attacks against SSL and TLS in recent years, but they should generally not concern you if you’re running up-to-date software and following the advice in this guide. (If you’re not, I’d advise testing your systems using SSL Labs and taking it from there.) However, nothing is perfectly secure, which is why it is a good practice to keep an eye on what happens in security. Promptly apply vendor patches if and when they become available; otherwise, rely on workarounds for mitigation.

3 Performance

Security is our main focus in this guide, but we must also pay attention to performance; a secure service that does not satisfy performance criteria will no doubt be dropped. With proper configuration, TLS can be quite fast. With modern protocols—for example, HTTP/2—it might even be faster than plaintext communication.

3.1 Avoid Too Much Security

The cryptographic handshake, which is used to establish secure connections, is an operation for which the cost is highly influenced by private key size. Using a key that is too short is insecure, but using a key that is too long will result in “too much” security and slow operation. For most web sites, using RSA keys stronger than 2,048 bits and ECDSA keys stronger than 256 bits is a waste of CPU power and might impair user experience. Similarly, there is little benefit to increasing the strength of the ephemeral key exchange beyond 2,048 bits for DHE and 256 bits for ECDHE. There are no clear benefits of using encryption above 128 bits.

3.2 Use Session Resumption

Session resumption is a performance-optimization technique that makes it possible to save the results of costly cryptographic operations and to reuse them for a period of time. A disabled or nonfunctional session resumption mechanism may introduce a significant performance penalty.

3.3 Use WAN Optimization and HTTP/2

These days, TLS overhead doesn’t come from CPU-hungry cryptographic operations, but from network latency. A TLS handshake, which can start only after the TCP handshake completes, requires a further exchange of packets and is more expensive the further away you are from the server. The best way to minimize latency is to avoid creating new connections—in other words, to keep existing connections open for a long time (keep-alives). Other techniques that provide good results include supporting modern protocols such as HTTP/2 and using WAN optimization (usually via content delivery networks).

3.4 Cache Public Content

When communicating over TLS, browsers might assume that all traffic is sensitive. They will typically use the memory to cache certain resources, but once you close the browser, all the content may be lost. To gain a performance boost and enable long-term caching of some resources, mark public resources (e.g., images) as public.

3.5 Use OCSP Stapling

OCSP stapling is an extension of the OCSP protocol that delivers revocation information as part of the TLS handshake, directly from the server. As a result, the client does not need to contact OCSP servers for out-of-band validation and the overall TLS connection time is significantly reduced. OCSP stapling is an important optimization technique, but you should be aware that not all web servers provide solid OCSP stapling implementations. Combined with a CA that has a slow or unreliable OCSP responder, such web servers might create performance issues. For best results, simulate failure conditions to see if they might impact your availability.

3.6 Use Fast Cryptographic Primitives

In addition to providing the best security, my recommended cipher suite configuration also provides the best performance. Whenever possible, use CPUs that support hardware-accelerated AES. After that, if you really want a further performance edge (probably not needed for most sites), consider using ECDSA keys.

4 HTTP and Application Security

The HTTP protocol and the surrounding platform for web application delivery continued to evolve rapidly after SSL was born. As a result of that evolution, the platform now contains features that can be used to defeat encryption. In this section, we list those features, along with ways to use them securely.

4.1 Encrypt Everything

The fact that encryption is optional is probably one of the biggest security problems today. We see the following problems:

  • No TLS on sites that need it
  • Sites that have TLS but that do not enforce it
  • Sites that mix TLS and non-TLS content, sometimes even within the same page
  • Sites with programming errors that subvert TLS

Although many of these problems can be mitigated if you know exactly what you’re doing, the only way to reliably protect web site communication is to enforce encryption throughout—without exception.

4.2 Eliminate Mixed Content

Mixed-content pages are those that are transmitted over TLS but include resources (e.g., JavaScript files, images, CSS files) that are not transmitted over TLS. Such pages are not secure. An active man-in-the-middle (MITM) attacker can piggyback on a single unprotected JavaScript resource, for example, and hijack the entire user session. Even if you follow the advice from the previous section and encrypt your entire web site, you might still end up retrieving some resources unencrypted from third-party web sites.

4.3 Understand and Acknowledge Third-Party Trust

Web sites often use third-party services activated via JavaScript code downloaded from another server. A good example of such a service is Google Analytics, which is used on large parts of the Web. Such inclusion of third-party code creates an implicit trust connection that effectively gives the other party full control over your web site. The third party may not be malicious, but large providers of such services are increasingly seen as targets. The reasoning is simple: if a large provider is compromised, the attacker is automatically given access to all the sites that depend on the service.

If you follow the advice from Section 4.2, at least your third-party links will be encrypted and thus safe from MITM attacks. However, you should go a step further than that: learn what services you use and remove them, replace them with safer alternatives, or accept the risk of their continued use. A new technology called subresource integrity (SRI) could be used to reduce the potential exposure via third-party resources.[3]

4.4 Secure Cookies

To be properly secure, a web site requires TLS, but also that all its cookies are explicitly marked as secure when they are created. Failure to secure the cookies makes it possible for an active MITM attacker to tease some information out through clever tricks, even on web sites that are 100% encrypted. For best results, consider adding cryptographic integrity validation or even encryption to your cookies.

4.5 Secure HTTP Compression

The 2012 CRIME attack showed that TLS compression can’t be implemented securely. The only solution was to disable TLS compression altogether. The following year, two further attack variations followed. TIME and BREACH focused on secrets in HTTP response bodies compressed using HTTP compression. Unlike TLS compression, HTTP compression is a necessity and can’t be turned off. Thus, to address these attacks, changes to application code need to be made.[4]

TIME and BREACH attacks are not easy to carry out, but if someone is motivated enough to use them, the impact is roughly equivalent to a successful Cross-Site Request Forgery (CSRF) attack.

4.6 Deploy HTTP Strict Transport Security

HTTP Strict Transport Security (HSTS) is a safety net for TLS. It was designed to ensure that security remains intact even in the case of configuration problems and implementation errors. To activate HSTS protection, you add a new response header to your web sites. After that, browsers that support HSTS (all modern browsers at this time) enforce it.

The goal of HSTS is simple: after activation, it does not allow any insecure communication with the web site that uses it. It achieves this goal by automatically converting all plaintext links to secure ones. As a bonus, it also disables click-through certificate warnings. (Certificate warnings are an indicator of an active MITM attack. Studies have shown that most users click through these warnings, so it is in your best interest to never allow them.)

Adding support for HSTS is the single most important improvement you can make for the TLS security of your web sites. New sites should always be designed with HSTS in mind and the old sites converted to support it wherever possible and as soon as possible. For best security, consider using HSTS preloading,[5] which embeds your HSTS configuration in modern browsers, making even the first connection to your site secure.

The following configuration example activates HSTS on the main hostname and all its subdomains for a period of one year, while also allowing preloading:

Strict-Transport-Security: max-age=31536000; includeSubDomains; preload

4.7 Deploy Content Security Policy

Content Security Policy (CSP) is a security mechanism that web sites can use to restrict browser operation. Although initially designed to address Cross-Site Scripting (XSS), CSP is constantly evolving and supports features that are useful for enhancing TLS security. In particular, it can be used to restrict mixed content when it comes to third-party web sites, for which HSTS doesn’t help.

To deploy CSP to prevent third-party mixed content, use the following configuration:

Content-Security-Policy: default-src https: 'unsafe-inline' 'unsafe-eval';
                         connect-src https: wss:

Note

This is not the best way to deploy CSP. In order to provide an example that doesn’t break anything except mixed content, I had to disable some of the default security features. Over time, as you learn more about CSP, you should change your policy to bring them back.

4.8 Do Not Cache Sensitive Content

All sensitive content must be communicated only to the intended parties and treated accordingly by all devices. Although proxies do not see encrypted traffic and cannot share content among users, the use of cloud-based application delivery platforms is increasing, which is why you need to be very careful when specifying what is public and what is not.

4.9 Consider Other Threats

TLS is designed to address only one aspect of security—confidentiality and integrity of the communication between you and your users—but there are many other threats that you need to deal with. In most cases, that means ensuring that your web site does not have other weaknesses.

5 Validation

With many configuration parameters available for tweaking, it is difficult to know in advance what impact certain changes will have. Further, changes are sometimes made accidentally; software upgrades can introduce changes silently. For that reason, we advise that you use a comprehensive SSL/TLS assessment tool initially to verify your configuration to ensure that you start out secure, and then periodically to ensure that you stay secure. For public web sites, we recommend the free SSL Labs server test.[6]

6 Advanced Topics

The following advanced topics are currently outside the scope of our guide. They require a deeper understanding of SSL/TLS and Public Key Infrastructure (PKI), and they are still being debated by experts.

6.1 Public Key Pinning

Public key pinning is designed to give web site operators the means to restrict which CAs can issue certificates for their web sites. This feature has been deployed by Google for some time now (hardcoded into their browser, Chrome) and has proven to be very useful in preventing attacks and making the public aware of them. In 2014, Firefox also added support for hardcoded pinning. A standard called Public Key Pinning Extension for HTTP[7] is now available. Public key pinning addresses the biggest weakness of PKI (the fact that any CA can issue a certificate for any web site), but it comes at a cost; deploying requires significant effort and expertise, and creates risk of losing control of your site (if you end up with invalid pinning configuration). You should consider pinning largely only if you’re managing a site that might be realistically attacked via a fraudulent certificate.

6.2 DNSSEC and DANE

Domain Name System Security Extensions (DNSSEC) is a set of technologies that add integrity to the domain name system. Today, an active network attacker can easily hijack any DNS request and forge arbitrary responses. With DNSSEC, all responses can be cryptographically tracked back to the DNS root. DNS-based Authentication of Named Entities (DANE) is a separate standard that builds on top of DNSSEC to provide bindings between DNS and TLS. DANE could be used to augment the security of the existing CA-based PKI ecosystem or bypass it altogether.

Even though not everyone agrees that DNSSEC is a good direction for the Internet, support for it continues to improve. Browsers don’t yet support either DNSSEC or DANE (preferring similar features provided by HSTS and HPKP instead), but there is some indication that they are starting to be used to improve the security of email delivery.

7 Changes

The first release of this guide was on 24 February 2012. This section tracks the document changes over time, starting with version 1.3.

Version 1.3 (17 September 2013)

The following changes were made in this version:

  • Recommend replacing 1024-bit certificates straight away.
  • Recommend against supporting SSL v3.
  • Remove the recommendation to use RC4 to mitigate the BEAST attack server-side.
  • Recommend that RC4 is disabled.
  • Recommend that 3DES is disabled in the near future.
  • Warn about the CRIME attack variations (TIME and BREACH).
  • Recommend supporting forward secrecy.
  • Add discussion of ECDSA certificates.

Version 1.4 (8 December 2014)

The following changes were made in this version:

  • Discuss SHA1 deprecation and recommend migrating to the SHA2 family.
  • Recommend that SSL v3 is disabled and mention the POODLE attack.
  • Expand Section 3.1 to cover the strength of the DHE and ECDHE key exchanges.
  • Recommend OCSP Stapling as a performance-improvement measure, promoting it to Section 3.5.

Version 1.5 (8 June 2016)

The following changes were made in this version:

  • Refreshed the entire document to keep up with the times.
  • Recommended use of authenticated cipher suites.
  • Spent more time discussing key exchange strength and the Logjam attack.
  • Removed the recommendation to disable client-initiated renegotiation. Modern software does this anyway, and it might be impossible or difficult to disable it with something older. At the same time, the DoS vector isn’t particularly strong. Overall, I feel it’s better to spend available resources fixing something else.
  • Added a warning about flaky OCSP stapling implementations.
  • Added mention of subresource integrity enforcement.
  • Added mention of cookie integrity validation and encryption.
  • Added mention of HSTS preloading.
  • Recommended using CSP for better handling of third-party mixed content.
  • Mentioned FREAK, Logjam, and DROWN attacks.
  • Removed the section that discussed mitigation of various TLS attacks, which are largely obsolete by now, especially if the advice presented here is followed. Moved discussion of CRIME variants into a new section.
  • Added a brief discussion of DNSSEC and DANE to the Advanced section.

Version 1.6 (15 January 2020)

The following changes were made in this version:

  • Refreshed the entire document to keep up with the times.
  • Added details to use SAN (Subject Alternative Names) since the Common Name is deprecated by latest browsers.
  • SHA1 signature deprecation for leaf and intermediate certificate
  • Added DNS CAA information, recommened the use of it.
  • Added information about the extra download of missing intermediate certificate and the sequence of it.
  • Recommended the use of TLS 1.3
  • Recommended not to use the legacy protocol TLS v1.0 and TLS v1.1
  • Improved the secure cipher suites section with more information and newly discovered weak/insecure cipher.
  • Updated HSTS preload footnotes link.

Acknowledgments

Special thanks to Marsh Ray, Nasko Oskov, Adrian F. Dimcev, and Ryan Hurst for their valuable feedback and help in crafting the initial version of this document. Also thanks to many others who generously share their knowledge of security and cryptography with the world. The guidelines presented here draw on the work of the entire security community.

About SSL Labs

SSL Labs (www.ssllabs.com) is Qualys’s research effort to understand SSL/TLS and PKI as well as to provide tools and documentation to assist with assessment and configuration. Since 2009, when SSL Labs was launched, hundreds of thousands of assessments have been performed using the free online assessment tool. Other projects run by SSL Labs include periodic Internet-wide surveys of TLS configuration and SSL Pulse, a monthly scan of about 150,000 most popular TLS-enabled web sites in the world.

About Qualys

Qualys, Inc. (NASDAQ: QLYS) is a pioneer and leading provider of cloud-based security and compliance solutions with over 9,300 customers in more than 100 countries, including a majority of each of the Forbes Global 100 and Fortune 100. The Qualys Cloud Platform and integrated suite of solutions help organizations simplify security operations and lower the cost of compliance by delivering critical security intelligence on demand and automating the full spectrum of auditing, compliance and protection for IT systems and web applications. Founded in 1999, Qualys has established strategic partnerships with leading managed service providers and consulting organizations including Accenture, BT, Cognizant Technology Solutions, Deutsche Telekom, Fujitsu, HCL, HP Enterprise, IBM, Infosys, NTT, Optiv, SecureWorks, Tata Communications, Verizon and Wipro. The company is also a founding member of the Cloud Security Alliance (CSA). For more information, please visit www.qualys.com.

[1] Transport Layer Security (TLS) Parameters (IANA, retrieved 18 March 2016)

[2] Weak Diffie-Hellman and the Logjam Attack (retrieved 16 March 2016)

[3] Subresource Integrity (Mozilla Developer Network, retrieved 16 March 2016)

[4] Defending against the BREACH Attack (Qualys Security Labs; 7 August 2013)

[5] HSTS Preload List (Google developers, retrieved 16 March 2016)

[6] SSL Labs (retrieved 16 March 2016)

[7] RFC 7469: Public Key Pinning Extension for HTTP (Evans et al, April 2015)

[8] RFC 6844: DNS CAA (Evans et al, January 2013)

Source :
https://github.com/ssllabs/research/wiki/SSL-and-TLS-Deployment-Best-Practices

Warning: Unnecessary HSTS header over HTTP

we would like to add the HSTS header to our page https://www.wipfelglueck.de
Our page is running on a shared server, so we don’t have access to the httpd.conf. We tried to enable this header via the .htaccess file like this:

<ifmodule mod_headers.c>
  DefaultLanguage de
  Header set X-XSS-Protection "1; mode=block"
  Header set X-Frame-Options "sameorigin"
  Header set X-Content-Type-Options "nosniff"
  
  Header set X-Permitted-Cross-Domain-Policies "none"
  
  Header always set Strict-Transport-Security "max-age=31536000; includeSubDomains; preload"
  
  Header set Referrer-Policy: no-referrer
  
  <FilesMatch "\.(js|css|xml|gz)$"> 
    Header append Vary Accept-Encoding 
  </FilesMatch> 
   
  <filesMatch ".(ico|jpg|jpeg|png|gif|webp)$">
   Header set Cache-Control "max-age=2592000, public"
  </filesMatch>
  <filesMatch ".(css|js|json|html)$">
   Header set Cache-Control "max-age=604800, public"
  </filesMatch>
</IfModule>

When we check the page we receive the warning in subject with this text:
“The HTTP page at http://wipfelglueck.de sends an HSTS header. This has no effect over HTTP, and should be removed.”

I tried some ways to solve this, but was not successful so far. In the web I can’t find a solution, so I would be happy if you could give me a hint on this!

Thank you very much!!

Thank you very much for your respond!
With the header:

Header always set Strict-Transport-Security "max-age=31536000; includeSubDomains; preload" env=HTTPS

or

Header set Strict-Transport-Security "max-age=31536000; includeSubDomains; preload" env=HTTPS

there is no error, the page runs, but when I check the page this error is mentioned:

Error: No HSTS header
Response error: No HSTS header is present on the response.

That’s strange. What did I wrong?

Answer

You can conditionally set headers using env=

Header always set Strict-Transport-Security "..." env=HTTPS

(you can use both always and env= simultaneously, the former only filters by response status)

That being said, do not optimize for benchmarks or compliance checkmarks. This header does not do anything, caring about it just takes away attention from things that do have effects. This header simply has no effect when not sent via secured transports – but as these days, (almost) all plaintext requests should just redirect to https://, this is true for (almost) any response header in http://.

Source :
https://bootpanic.com/warning-unnecessary-hsts-header-over-http/

How to Find the Source of Account Lockouts in Active Directory

In this post, you will learn how to find the source of account lockouts in Active Directory.

Here are the steps to find the source of account lockouts:

Users locking their accounts is a common problem, it’s one of the top calls to the helpdesk.

What is frustrating is when you unlock a user’s account and it keeps randomly locking. The user could be logged into multiple devices (phone, computer, application, and so on) and when they change their password it will cause ongoing lock-out issues.

This guide will help you to track down the source of those lockouts.

Check it out:

Step 1: Enabling Auditing Logs

The first step to tracking down the source of account lockouts is to enable auditing. If you do not turn on the proper auditing logs then the lockout events will not be logged.

Here are the steps to turn on the audit logs:

1. Open Group Policy Management Console

This can be from the domain controller or any computer that has the RSAT tools installed.

2. Modify Default Domain Controllers Policy

Browse to the Default Domain Controllers Policy, right-click, and select edit. You can also create a new GPO on the “Domain Controllers” OU if you prefer to not edit the default GPO.

3. Modify the Advanced Audit Policy Configuration

Browse to computer configuration -> Policies -> Security Settings -> Advanced Audit Policy Configuration -> Audit Policies -> Account Management

Enable success and failure for the “Audit User Account Management” policy.

Next, enable the following:

computer configuration -> Security Settings -> Advanced Audit Policy Configuration -> Audit Policies -> Account Logon

Enable Success and Failure for “Audit Kerberos Authentication Service.”

Auditing is now turned on and event 4740 will be logged in the security events logs when an account is locked out. In addition, the Kerberos logs are enabling which will log authentication failures with the lockout. Sometimes event 4740 does not log the source computer and the Kerberos logs provide additional details.

Step 2: Using the User Unlock GUI Tool to Find the Source of Account Lockouts

This step uses the User Unlock Tool to find the event ID 4740 and other event IDs that will help troubleshoot lockouts.

I created this tool to make it super easy for any staff member to unlock accounts, reset passwords and find the source of account lockouts. It also has some additional features to help find the source of lockouts.

This is a much easier option than PowerShell.

1. Open the AD Pro Toolkit

You can download a free trial here.

Click on the “User Unlock” tool in the left side menu.

Step 2. Select Troubleshoot Lockouts

Select Troubleshoot lockouts and click run

You will now have a list of events that will show the source of a lockout or the source of bad authentication attempts.

In the above screenshot, you can see the account “robert.allen” lockout came from computer PC1.

There will be times when event 4740 does not show the source computer. When that happens you can use the other logged events to help troubleshoot log out events. For example, if the above screenshot had no event 4740 I can look at 4771 and see the failed authentication attempt was from a computer with the IP 192.168.100.20.

In addition, you can unlock the account and reset the password all from one tool. The tool will display all locked accounts, you can select a single account or multiple accounts to unlock.

The unlock tool is part of the AD Pro Toolkit. Download your free trial here.

Step 3: Using PowerShell to Find the Source of Account Lockouts

Both the PowerShell and the GUI tool need auditing turned before the domain controllers will log any useful information.

1. Find the Domain Controller with the PDC Emulator Role

If you have a single domain controller (shame on you) then you can skip to the next step…hopefully you have at least two DCs.

The DC with the PDC emulator role will record every account lockout with an event ID of 4740.

To find the DC that has the PDCEmulator role run this PowerShell command

get-addomain | select PDCEmulator

2: Finding event ID 4740 using PowerShell

All of the details you need are in event 4740. Now that you know which DC holds the pdcemulator role you can filter the logs for this event.

On the DC holding the PDCEmulator role open PowerShell and run this command

Get-WinEvent -FilterHashtable @{logname=’security’; id=4740}

This will search the security event logs for event ID 4740. If you have any account lockouts you should see a list like the below.

To display the details of these events and get the source of the lockout use this command.

Get-WinEvent -FilterHashtable @{logname=’security’; id=4740} | fl

This will display the caller computer name of the lockout. This is the source of the user account lockout.

You can also open the event log and filter the events for 4740

Although this method works it takes a few manual steps and can be time consuming. You may also have staff that is not familiar with PowerShell and need to perform other functions like unlock or reset the user’s account.

That is why I created the Active Directory User Unlock GUI tool. This tool makes it super easy for staff to find all locked users and the source of account lockouts.

I hope you found this article useful. If you have questions or comments let me know by posting a comment below.

Source :
https://activedirectorypro.com/find-the-source-of-account-lockouts/

UniFi Network – WAN Failover and Load Balancing

What is WAN Failover?
Failover enables you to connect a second Internet connection to your UniFi Gateway which will serve as a “backup”. If your primary Internet service goes down, you will begin utilizing your secondary Internet connection.

How does UniFi determine if my Internet goes down?
The UniFi Network Application checks for connectivity and latency to an “echo server”. By default, this is set to ping.ui.com which leverages responses from various locations to ensure maximum accuracy. 

Note: Some advanced network administrators may choose to manually select their own echo server depending on their specific requirements.

What is WAN Load Balancing?
Unlike WAN Failover which only uses a single Internet source at a given time, WAN Load Balancing will split Internet traffic between both of your sources. This will be supported by UniFi Gateways beginning in version 1.13 (UDM Pro / UXG Pro) and 2.5 (UDM SE).

How many Internet connections are my UniFi Gateways capable of?
In addition to the two WAN connections, UniFi Gateways also support the use of our UniFi LTE Backup which is connected to a LAN port. This is only capable of being used as a failover option.

Source :
https://help.ui.com/hc/en-us/articles/360052548713-UniFi-Network-WAN-Failover-and-Load-Balancing

UniFi Network – Configuring Port Forwarding

Create Port Forwarding rules within UniFi Network in the Settings > Firewall & Security section. Refer to the troubleshooting steps below if your Port Forwarding or custom Destination NAT rule is not working.

Your UniFi Gateway does not have a public IP address (Double NAT).
This happens if your UniFi Gateway is located behind another router/modem that uses NAT. You are likely affected by this if your UniFi Gateway has a WAN IP address in one of the following ranges:

  • 10.0.0.0/8 (10.0.0.0 – 10.255.255.255)
  • 172.16.0.0/12 (172.16.0.0 – 172.31.255.255)
  • 192.168.0.0/16 (192.168.0.0 – 192.168.255.255)
  • 100.64.0.0/10 (100.64.0.0 – 100.127.255.255)

To fix this issue, try to re-configure your ISP modem/router into bridge mode so that your UniFi Gateway can obtain a public IP address on the WAN interface.

If that is not supported, you will need to first forward the port(s) on the upstream router/modem to the WAN address of your UniFi Gateway in addition to forwarding them from your UniFi Gateway to the desired location. You may wish to contact your ISP to assist with port forwarding or providing a DMZ option that allows you to automatically forward the ports.

Your UniFi Gateway is already forwarding the port to another device or has UPnP enabled.
A given WAN port can only be forwarded to a single device within your network. For example, TCP port 443 can only be forwarded to one LAN port.

Note: It is possible to forward multiple WAN ports to the same LAN port.

Another possible cause is that UPnP is enabled and is already using the port. Try disabling UPnP in your UniFi Network Application’s Internet Settings.

Incoming traffic is not reaching the WAN interface of your UniFi Gateway.
In this case, the traffic is most likely blocked somewhere upstream, such as at the ISP modem/router, or a third party firewall. We recommend disabling any upstream firewalls for testing, and then contacting your ISP for more details.

The LAN host is blocking the port with a local firewall, or does not have the correct route configured.
In this case, the host/server on the LAN is not allowing outside connections to access the port. On Windows computers, this may be a result of the Windows Firewall rules. On Linux machines, this could be a result of the connection not being allowed in the iptables firewall. We recommend consulting with the particular client’s manufacturer for more information.

There is an incorrect route configured on the LAN host.
It is possible that the LAN host does not know how to reach the IP address of the Internet client. This can result if the default gateway is not configured correctly. You should verify your routing settings on the local host to resolve this situation.

Source :
https://help.ui.com/hc/en-us/articles/235723207-UniFi-Network-Configuring-Port-Forwarding

UniFi Network – Configuring Remote Access VPNs (VPN Server)

We strongly recommend Teleport VPN for most users seeking to remotely access their UniFi OS Console’s network. It’s faster, more secure, and requires zero configuration. 

For more information about Teleport and other VPN options, see our Introduction to UniFi VPNs.

Setup

VPN server configuration requires a UniFi gateway and a public IP address. We recommend obtaining a static public IP address from your ISP to avoid having to reconfigure all of your clients every time your IP changes. Your UniFi gateway will automatically update server-side settings.

Note: Dynamic DNS can be used to avoid reconfiguring your clients’ VPN when IP changes occur, but this process is not outlined here.

To set up a VPN server, you must create a Pre-shared Key (UniFi generates a secure one automatically) and user credentials (Username and Password) that are entered on clients to authenticate their remote network access. 

Note: Users are linked to the UniFi gateway’s internal RADIUS server. Although UniFi supports third-party RADIUS server integration, we recommend contacting the third-party server provider if you have troubleshooting questions.

Configuring Clients

You can connect any L2TP VPN client, including those provided by Microsoft Windows or macOS. We recommend using your operating system’s native VPN client.

Although we outline OS-specific client configuration processes below, we still recommend consulting your device’s manufacturer on how to use their platform’s VPN client.

Microsoft Windows 11

  1. Go to Settings > Network & internet > VPN > VPN connections > Add VPN and select L2TP/IPsec with pre-shared key as your VPN type.

    Note: Your username, password, and pre-shared key are the same as those in your UniFi Network settings.
  2. Go to Settings > Network & internet > Advanced network settings > More network adapter options > L2TP Adapter properties
  3. Click the Security tab, then set your authentication method to MS-CHAP v2.

macOS

  1. Go to System Preferences > Network > +. 
  2. Select VPN in the Interface field.
  3. Select L2TP over IPsec in the VPN Type field.
  4. Enter l2tp as the Service Name.

    Note: Your username, password, and pre-shared key are the same as those in your UniFi Network settings.
  5. Route all traffic through the VPN by going to Options > Session Options and selecting Send all traffic over VPN connection.

Troubleshooting

If your client cannot connect to the VPN server, or is unable to route traffic through the VPN, you may receive error messages stating that the server is not responding, the client disconnected, or that a processing error occurred. Your VPN connection may also fail. These events are likely related to one of the following:

Your UniFi Gateway Does Not Have a Public IP Address (Double NAT)

This typically occurs if your UniFi gateway is located behind another router/modem that uses Network Address Translation (NAT). You are likely affected if your UniFi gateway has a WAN IP address in one of the following ranges:

  • 10.0.0.0/8 (10.0.0.0 – 10.255.255.255)
  • 172.16.0.0/12 (172.16.0.0 – 172.31.255.255)
  • 192.168.0.0/16 (192.168.0.0 – 192.168.255.255)
  • 100.64.0.0/10 (100.64.0.0 – 100.127.255.255)

To resolve this, set your upstream router to Bridge Mode. If this is not possible, try forwarding UDP Ports 500 and 4500 from the upstream router/modem to your UniFi gateway. Please note that this will not work if your upstream router doesn’t have a public IP address. 

Note: By default, Windows computers cannot establish L2TP VPN connections with servers behind NAT. To get around this restriction, you will need to manually change the AssumeUDPEncapsulationContextOnSendRule registry value from 0 to 2. For more details, please refer to Microsoft’s support page.

For help configuring your device to bridge mode or port forwarding, we recommend contacting your ISP for further assistance. Please note that IP addresses in the 100.64.0.0/10 subnet range always require ISP assistance in order to establish a VPN connection.

Required Ports Are Blocked by an Upstream Device or Forwarded by Your UniFi Gateway to Another Device on Your Local Network

Make sure that no third-party routers, firewalls, or ISP modems are blocking UDP Ports 500 or 4500 from reaching your UniFi gateway. You may need to contact your ISP to verify that your network traffic is being routed correctly.

Once you confirm that your traffic is not being blocked, please ensure that your UniFi gateway is not forwarding these ports to another device on your local network. You can remove existing port forwarding rules in the Firewall & Security section of your UniFi Network application.

Authentication Failures Due to Incorrect Configuration

This occurs when the VPN server and client have mismatching pre-shared keys, authentication methods, or login credentials. Please ensure that all of these match what is configured in your UniFi Network application. Also, ensure that client devices are using the MS-CHAP v2 authentication method, and that the VPN type is set to L2TP. Lastly, verify that you are authenticating with a pre-shared key and not a certificate. 

Re-enter the pre-shared key, username, and password and check for typos.

Your Client Cannot Establish an L2TP Connection

Try using a different client or operating system to verify if this is a client-specific issue. If so, check for any device updates or contact the manufacturer for further assistance.

Note: Most Android clients require you to enable Weak Ciphers in your UniFi Network’s VPN server configuration.

Your Client Is Routing Over the VPN, but Its Traffic is Prohibited

In this scenario, the client can connect to the VPN but cannot communicate with any other devices on the local network.

To resolve this, please ensure that there are no traffic or firewall rules preventing VPN clients from communicating with your local network. Alternatively, individual clients on the local network could be dropping incoming traffic at their local firewalls. The Windows firewall, for example, drops all ICMPv4 (ping) traffic by default. 

If you are testing with ping, then you will need to allow this traffic through the Windows firewall. For more details, please refer to the Microsoft support page.

The Client and VPN Server Use the Same Local IP Range

In this scenario, the client can connect to the VPN but cannot communicate with any devices on the local network. This could be because the client has an IP address that overlaps with the subnet of the network it is attempting to connect to. 

For example, if your client has a 192.168.3.21 address on its local network, and it is trying to connect to the UniFi VPN server configured on the 192.168.3.0/24 subnet, the client will always utilize its local network connection instead of the VPN. To resolve this, either change the client’s local IP or adjust your UniFi Network subnet range.

Your Client Has Split Tunneling

This will prevent clients from communicating with certain VPN-connected devices despite being connected to the network itself. To resolve this, we recommend routing all traffic through your VPN:

  • For Windows clients, enable Use default gateway on remote network in the Advanced TCP/IP Settings.
  • For Mac clients, enable Send all traffic over VPN connection in your VPN network preferences.

For more OS-specific guidance, please contact your device’s manufacturer.

Expedite Your Support Request

If you’re submitting a support request, please include answers to the following to ensure that our Support Engineers are fully apprised of your unique situation and can deliver the best, most personalized support experience possible.

  • What is the model and operating system of each affected client?
  • What error message(s) are you receiving?
  • How are your client(s) configured? (Please provide screenshot(s), if possible.)
  • Have you tested this on a different client?
  • How is each client attempting to connect to the VPN? Is it using LTE data, or is it connected to a different WiFi network?
  • What is the IP address of each affected client, and what is your UniFi gateway’s VPN server subnet range?

Also, please provide a copy of your support file, along with a timestamp of when you last attempted to connect to the VPN server. More detailed instructions can be found here.

UniFi – Maintaining Connectivity with your UniFi Devices

A UniFi device with an Offline state has lost communication with its application host meaning that you will be unable to manage its configuration. This does not necessarily mean it has stopped working. As long as it is powered on with connectivity to the rest of your network it will continue operating in a “Self-Run” state using the last known UniFi configuration.

A UniFi device can go offline for a number of reasons, but this is most common for those with third-party equipment, or those that choose to self-host the Network Application instead of using a UniFi OS Console.

Here are the most common reasons why UniFi devices go offline:

Physical Connection Issues

Device connection can be disrupted by faulty cabling, power supply issues, or other problems with your physical networking hardware. First, ensure that your device is being powered by Power-over-Ethernet (PoE). Then, replace its cabling, confirm that both ends are securely connected, and try a new port to rule out physical damage. 

Device Cannot Obtain an IP Address from Your DHCP server

This is most common for users with a third-party DHCP server. To fix this, start by verifying that the device has been assigned a correct IP and gateway. You can do this by reviewing your server’s DHCP leases, or you can scan your network with the WiFiman mobile app (Android / iOS). 

Note: 192.168.1.20 is used as a fallback IP address, so its usage may indicate that your device cannot obtain another IP from your DHCP server.

Please also verify that your DHCP server’s network is added as a member of all your switch port profiles. Additionally, ensure that UDP Ports 67 and 68 are open on any firewalls on your network. Otherwise, none of your devices will be able to obtain an IP address and connect to your network.

Your Wirelessly Adopted Devices Have Poor Connectivity

A wirelessly adopted device is like any other wireless client. See Optimizing Wireless Client Connectivity for more details.

Firewall Blockages

This is the most common for users self-hosting the Network Application, especially on Windows hosts. For troubleshooting purposes, we recommend temporarily disabling your firewalls to verify if they are preventing your UniFi devices from coming online.

Please also note that some Windows updates can reconfigure your firewall settings. As such, please ensure that your firewall is set to Private. 

Next, verify that TCP Port 8080 and UDP Port 10001 are both open. For instructions on how to verify other required port configurations, see our Required Ports Reference.

If you have any Layer 3-adopted APs, please disable any custom firewall rules blocking traffic across VLANs between your UniFi device and the Network Application. 

Your Network Application Host Moved or Its IP Address Changed

If you change the location of your UniFi Network host, your devices could still be attempting to communicate with its old IP address. If the old and new IPs are on the same Layer 2 network (i.e,. same subnet and VLAN), your devices will be able to re-discover and reconnect to your host. 

If you moved the Network host to a new VLAN, however, you must use Layer 3 Adoption to re-establish connectivity. This should only be done by advanced users. Otherwise, we recommend reconfiguring your setup so that your Network Application and UniFi devices are on the same Layer 2 network.

Those who have performed a Layer 3 adoption should also verify if their public IP address has changed. This happens if your ISP provides IP addresses via DHCP. An IP address change will leave your L3-adopted devices still trying to communicate with the old IP address. We recommend using a Dynamic DNS (DDNS) service to avoid this. 

The Management VLAN Is Not a Member of Your Switch Port Profile

Your UniFi device’s Management VLAN must be a member of all switch ports. The Management VLAN configuration is found in the Settings tab of the device’s properties panel, which can be accessed by selecting it on the UniFi Device page.

Packet Loss and High Latency Between the UniFi Network Application and Device 

The UniFi Network Application has a 60-second disconnection threshold, meaning that it will wait one minute for a response from the device before declaring it disconnected. Packet loss and increased network latency can occasionally trigger device disconnections.

Expedite Your Support Request

Prior to reaching out to support, we recommend gathering/verifying the following information. Including these details in your request will expedite your support experience.

  • How are you hosting your UniFi Network Application (i.e., UniFi OS Console vs. self-hosted)?
  • What is your UniFi Network Application version? Please refer to our Software Releases page to confirm if you have the latest version.
  • What is the model and firmware version of your device? Please refer to our Software Releases page to confirm if you have the latest version.
  • Does your device frequently change statuses, or is it stuck in an Offline state?
  • When did this issue begin? Did you make any notable changes prior to it occurring?

Also, please provide a copy of your support file, along with the MAC address(es) of all affected device(s). More detailed instructions can be found here.

UniFi Network – Configuring Site-to-Site VPNs

Site-to-site VPNs are primarily used by businesses looking to connect numerous remote locations. If you are a home user, we strongly recommend Teleport VPN—our fast, secure, one-click remote access solution that requires no configuration. 

To learn more about Teleport and other UniFi VPN options, check out our Introduction to UniFi VPNs.

Setup

UniFi gateways support two site-to-site VPN protocols: IPsec and OpenVPN. Depending on the one you select, you will need to ensure that the following settings are the same for all gateways used to create site-to-site connections:

We recommend using UniFi gateways at all of your sites to maximize connection compatibility and performance. Additionally, some third-party gateways allow you to configure settings that are unavailable in the UniFi Network application. Troubleshooting these types of settings lies outside of Ubiquiti Support’s scope, but you can check out our Considerations for Third-Party Equipment: Site-to-Site VPNs for more information.

IPsec

  • Pre-Shared Key: This is used to authenticate VPN connections. 
  • UniFi Gateway IP: This is your UniFi gateway’s public IP address.
  • Shared Remote Subnets: This is the list of networks shared by the remote gateway. Please note that UniFi gateways share all local networks. You must ensure that there are no overlaps within your sites’ local subnets.
  • Remote IP: This is the remote gateway’s WAN IP address.

Additional Notes:

  • There are also Advanced settings that should match across all gateways. We recommend using the default settings unless you are proficient with VPN security.
  • Your UniFi gateway will automatically create the static routes required to direct traffic through the VPN. Do not try to create new ones for this purpose.

OpenVPN

The OpenVPN Site-to-site VPN uses a 512-character pre-shared key for authentication. The key should be the same for both gateways and shouldn’t contain line breaks. You can either create this key yourself or generate it on your UniFi gateway. To do this:

  1. SSH into your UniFi gateway.
  2. Generate your key by using the following command: openvpn –genkey secret /tmp/ovpn
  3. You can now view/copy the key by running the command: cat /tmp/ovpn
    Note: Be sure to remove any line breaks when copying the key.

Note: USGs must use generate vpn openvpn-key /tmp/ovpn to generate the key, then sudo cat /tmp/ovpn to view/copy the key.

Additionally, the following information is required:

  • Local Tunnel IP Address: This is the IP used for your local “tunnel”. Traffic sent to the remote gateway will be routed through this IP address. This address should be available on the local and remote site. We recommend selecting a private IP from a subnet that is unused on both gateways.
  • Local Port: By default, UDP Port 1194 is used for OvenVPN. This port must not be used by other services or other OpenVPN connections. If you’re using multiple OpenVPN tunnels, each one must be assigned to its own port. The local and remote ports do not need to be the same. 
  • Shared Remote Subnets: This is the list of networks shared by the remote gateway. Please note that UniFi gateways share all local networks. You must ensure that there are no overlaps within your sites’ local subnets.
  • Remote IP Address: This is the remote gateway’s WAN IP address.
  • Remote Tunnel IP Address: This is the IP address of the remote gateway’s tunnel. Do not enter the gateway’s WAN IP.
  • Remote Port: This is the remote gateway’s OpenVPN port. The local and remote ports do not need to be the same.

Note: Your UniFI gateway will automatically create the static routes required to direct traffic through the VPN. Do not try to create new ones for this purpose.

Troubleshooting

If you’re unable to establish a VPN tunnel between your sites, or your connection drops periodically, you likely have at least one site with an incorrect VPN or network configuration. Please refer to the common mistakes below.

Your UniFi Gateway Does Not Have a Public IP address (Double NAT)

This typically occurs if your UniFi Gateway is located behind another router/modem that uses Network Address Translation (NAT). You are likely affected if your UniFi Gateway has a WAN IP address in one of the following ranges:

  • 10.0.0.0/8 (10.0.0.0 – 10.255.255.255)
  • 172.16.0.0/12 (172.16.0.0 – 172.31.255.255)
  • 192.168.0.0/16 (192.168.0.0 – 192.168.255.255)
  • 100.64.0.0/10 (100.64.0.0 – 100.127.255.255)

To resolve this, set your upstream router to Bridge Mode. If this is not possible, try forwarding the necessary ports from the upstream router/modem to your UniFi gateway. IPsec uses UDP Port 500 and 4500. By default, OpenVPN uses UDP Port 1194, but this can be changed. Please note that this will not work if your upstream router doesn’t have a public IP address. 

If this doesn’t work, we recommend contacting your ISP. Please note that IP addresses in the 100.64.0.0/10 subnet range always require ISP assistance in order to establish a VPN connection.

Required Ports are Blocked by an Upstream Device or Forwarded by Your UniFi Gateway to Another Device on Your Local Network

Make sure that no third-party routers, firewalls, or ISP modems are blocking the required ports from reaching any of the gateways supporting your site-to-site VPN. IPsec uses UDP Port 500 and 4500. By default, OpenVPN uses UDP Port 1194, but this can be changed. Please note that if you reconfigure a port for one gateway, you must also reconfigure the same port for all other site-to-site VPN gateways.

Once you confirm that your traffic is not being blocked, please ensure that your UniFi gateway is not forwarding these ports to another device on your local network. You can remove existing port forwarding rules in the Firewall & Security section of your UniFi Network application.

Authentication Failures Due to Mismatched Gateway Configurations

Every gateway supporting your site-to-site VPN must have the same configuration, including Advanced settings. Failure to do so will prevent you from establishing a VPN connection or sustaining one for a long period of time.

We recommend using UniFi gateways at all of your sites to maximize connection compatibility and performance. This is because some third-party gateways allow you to configure settings that are not available in the UniFi Network application, but rather automatically set in the background. A mismatch in these configurations can still result in a connection failure. Troubleshooting these types of settings lies outside of Ubiquiti Support’s scope, but you can check out our Considerations for Third-Party Equipment: Site-to-Site VPNs for more information.

Also, please note that UniFi gateways are configured to share all local networks. Ensure these are configured in the paired gateway’s Shared Remote Subnets list.

Your Client Is Routing Over the VPN, but Its Traffic is Prohibited

In this scenario, the client can connect to the VPN but cannot communicate with any other devices on the local network.

To resolve this, please ensure that there are no traffic or firewall rules preventing VPN clients from communicating with your local network. Alternatively, individual clients on the local network could be dropping incoming traffic at their local firewalls. The Windows firewall, for example, drops all ICMPv4 (ping) traffic by default. 

If you are testing with ping, then you will need to allow the traffic through the Windows firewall. For more details, please refer to Microsoft’s support page.

Your Sites Have Overlapping IP Ranges

Overlapping IPs can prevent a VPN from establishing. Even if the VPN tunnel is established, it may prevent proper communication across the VPN. This is because a client will always prioritize IP addresses on a local network connection rather than those on the opposite end of a VPN. The only way to prevent overlapping is to review each gateway’s local networks and, if necessary, adjust their IP address ranges. For example, if one gateway has a local network configured to 192.168.0.0/24, its IP addresses range from 192.168.0.1 – 192.168.0.255. Your remote gateway should not use any addresses within that range.

Overlapping IPs ranges may prevent proper communication across your VPN, or it can prevent the connection from establishing altogether. Assuming the VPN establishes,

Your Client Has Split Tunneling

This will prevent clients from communicating with certain VPN-connected devices despite being connected to the network itself. To resolve this, we recommend routing all traffic through your VPN:

  • For Windows clients, enable Use default gateway on remote network in the Advanced TCP/IP Settings.
  • For Mac clients, enable Send all traffic over VPN connection in your VPN network preferences.

For more OS-specific guidance, please contact your device’s manufacturer.

Source :
https://help.ui.com/hc/en-us/articles/360002426234-UniFi-Network-Configuring-Site-to-Site-VPNs

UniFi Network – Optimizing Wired Network Speeds

The main factors that contribute to wired speeds are:

  • Physical (Layer 1) connections between your networking devices
  • Available device resources (e.g., CPU and Memory)
  • Protocol limitations
  • Software or configuration limitations

Follow these guidelines, and those in Optimizing Wireless Network Speeds, to maximize your total network throughput.

Recommendations 

Check Your Cabling

Make sure your cables are undamaged and securely connected to their respective ports. If your speeds are slower than you expect, swap out your cables for new ones. We recommend using SFP/SFP+ modules or DAC cables, when possible, to maximize speeds. Otherwise, use CAT6 RJ45 cables. 

Check out our Beginner’s Guide to Network Cabling for more information. 

Ensure That All Ports Negotiate Proper Speeds

All UniFi devices automatically negotiate their speeds. Some clients, however, may be incapable of doing so. For these devices, we recommend manually setting their link speed in the Port Management section,  found in the UniFi Devices tab of the Network Application. 

Please be sure to check each client’s specifications. Not all clients have a Network Interface Card (NIC) capable of negotiating at faster rates, such as 1 Gbps.

Note: Clients with speed negotiation issues often result in dropped connectivity. This is a telltale sign to look for if you suspect a client-specific issue.

Disable Resource-intensive Software Features

Resource-intensive features such as Threat Management and Smart Queues may reduce throughput by up to 30%. Please consider this when prioritizing network speed, performance, and security.

Note: Smart Queues are only recommended if you have expected Internet speeds of 250 Mbps or less and you consistently have more internet traffic than your bandwidth can support.

Other features that may impact throughput include: 

  • Device and Traffic Identification (Deep Packet Inspection)
  • Firewall Rules
  • Content Filters
  • VPNs 

To approximate your deployment’s resource usage, try our UniFi OS Console Resource Calculator. 

Note: These features will only affect traffic routed through your gateway or to the internet. It should not affect LAN traffic between devices on the same network.

Minimize Network Congestion

A high number of concurrent clients routing traffic through a local network device, like a single switch, may reduce throughput. To resolve this, we recommend separating network traffic or adopting an additional Layer 3 switch.

Be Aware of Protocol and Client Limitations

Certain protocols offer  lower performance. For example, L2TP VPNs are relatively slower compared to Wireguard or Teleport. Another example of a traditionally slow protocol is SMB file transfers.

Similarly, some clients may be limited by the resource intensity of the applications they run, independently of your network.

Use DHCP or Static WAN (Internet) Connection When Possible

PPPoE is a very CPU-intensive protocol that may reduce throughput compared to DHCP or Static IP configurations.

Remove Traffic Rules and Bandwidth Profiles That Limit Client Traffic

We always recommend taking a moment to verify that there are no active Traffic Rules or Bandwidth Profiles reducing client throughput.

Expedite Your Support Request

Please include answers to the following in your request to expedite your support experience:

  • What are your expected speeds?
  • How are you hosting your UniFi Network Application (i.e., UniFi OS Console vs. self-hosted)?
  • What version of UniFi Network are you running? What firmware versions are your network devices running (e.g., switches, APs, gateway, etc.)? Please refer to our Software Releases directory to verify everything is up-to-date.
  • If you are using a UniFi OS Console, what version of UniFi OS are you running? Please refer to our Software Releases directory to verify if you are running the most up-to-date UniFi OS.
  • How widespread is your throughput issue? Does it affect wired clients, wireless ones, both, or just certain devices?
  • When did this issue start?

    Source :
    https://help.ui.com/hc/en-us/articles/6949005136919-UniFi-Network-Optimizing-Wired-Network-Speeds