The utilization of WinRAR's self-extracting feature to plant backdoors has been detected by CrowdStrike.
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Hackers are using this feature to launch PowerShell, cmd.exe, and Task Manager without having to log in to a user's account by running a specific SFX archive through the utilman.exe application.
The SFX archive is protected with a password, and an empty text file is included in the archive. Since no virus is present in the archive, antivirus software may not detect the threat. Thus, having such an SFX file on a system can pose a significant security risk.
Backdoors in WinRAR archives refer to a potential security vulnerability wherein a crafted archive containing malicious code can be used to exploit a system. These backdoors can potentially extract themselves, allowing the malicious code to execute without the user's knowledge or consent.
The ability of a WinRAR archive to extract itself is dependent on various factors, including the presence of vulnerabilities in the software itself. In some cases, attackers can leverage vulnerabilities to manipulate the extraction process and execute malicious code automatically.
To protect against such backdoors, it is crucial to keep your WinRAR software up to date. Regularly installing updates and patches released by the developers can help mitigate known vulnerabilities. Additionally, running a reliable antivirus program can provide an added layer of defense by detecting and preventing the execution of malicious code.
It is essential to exercise caution when downloading and opening any files from untrusted sources, as this is usually how malware-laden WinRAR archives are distributed. Always verify the integrity and source of the files before extracting them, especially if they are obtained from unfamiliar or suspicious websites.
Backdoors in WinRAR archives can be created by malicious actors with the intent of gaining unauthorized access to a system or compromising its security. They exploit vulnerabilities in the WinRAR software to execute arbitrary code when the archive is extracted.
One example of a well-known backdoor in WinRAR archives is the vulnerability discovered in early 2019, known as "CVE-2018-20250." This vulnerability allowed an attacker to create a specially crafted archive that, when extracted using an unpatched version of WinRAR, would place malicious files in system startup locations. This would enable the execution of the malicious code every time the system restarted, potentially providing the attacker with persistent access to the compromised system.
To protect against such backdoors, it is important to keep your WinRAR software up to date. The developers frequently release patches and updates that address security vulnerabilities. By regularly installing these updates, you can ensure that you have the latest protections in place.
It is also crucial to exercise caution when opening WinRAR archives obtained from untrusted sources. Be vigilant and verify the integrity and source of the files before extracting them. Consider using reputable antivirus software, which can help identify and prevent the execution of malicious code.
examples of backdoors in WinRAR archives:
1. CVE-2018-20250: This vulnerability, discovered in 2019, allowed attackers to create malicious WinRAR archives that could extract files to arbitrary locations on the system. By exploiting this vulnerability, attackers could place executable files in system startup folders and execute them automatically upon system restart, potentially gaining persistent access to the compromised system.
2. ACE Vulnerability: In 2018, another vulnerability was discovered in the third-party library called UNACEV2.DLL, which was used by WinRAR to handle ACE archive format. Attackers could create specially crafted ACE archives containing a malicious payload, which, when extracted with an unpatched version of WinRAR, could execute arbitrary code on the system.
Here are a few more examples of vulnerabilities and exploits in WinRAR that have been reported in the past:
1. CVE-2005-6334: This vulnerability affected WinRAR versions prior to 3.50. It allowed attackers to execute arbitrary code by creating a specially crafted RAR archive that exploited a buffer overflow.
2. CVE-2012-5228: This vulnerability was discovered in WinRAR 4.20 and earlier versions. It allowed attackers to execute arbitrary code by tricking users into extracting a ZIP archive containing a malicious DLL file.
3. CVE-2018-20251: This vulnerability affected WinRAR versions prior to 5.61. It allowed attackers to bypass the filename encoding check, enabling them to place files with arbitrary names in arbitrary locations during extraction.