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2025-02-06
The 7-Zip Mark-of-the-Web (MOTW) Bypass vulnerability is a significant security flaw that has been identified in 7-Zip, a popular open-source file archiver. This vulnerability poses a risk to users, especially those who handle archived files, as it allows attackers to bypass the MOTW protection mechanism. In this article, we’ll delve into the details of this vulnerability, the potential impact it could have on users, and why it is critical to stay informed and proactive about such security issues.
the Vulnerability
The Mark-of-the-Web (MOTW) bypass vulnerability in 7-Zip occurs due to improper handling of archived files that bear the MOTW. When extracting files from an archive marked with MOTW, 7-Zip fails to propagate this flag to the extracted files. This failure enables malicious actors to exploit the vulnerability by using crafted archives that bypass the MOTW protection, allowing the execution of arbitrary code under the user’s privileges. The attack requires user interaction, meaning the target must either open a malicious file or visit a malicious webpage that contains such an archive.
The issue, identified as ZDI-CAN-25456, was assigned a CVSS score of 7.0, indicating a high severity risk. The vulnerability affects version 3.0 of 7-Zip and can lead to significant security breaches if exploited.
CVSS Score Overview
– CVSS Score: 7.0 (High)
– Vector String: CVSS:3.0/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
– Severity: High
- Impact: Arbitrary code execution in the context of the current user.
References
– Zero Day Initiative Advisory: [ZDI-25-045](https://www.zerodayinitiative.com/advisories/ZDI-25-045)
What Undercode Says:
The 7-Zip Mark-of-the-Web (MOTW) bypass vulnerability represents a clear and present danger for individuals who rely on 7-Zip to manage their compressed files. Despite 7-Zip’s widespread use, especially in tech-savvy environments, this vulnerability highlights a critical flaw in how archived files are handled when marked with the MOTW tag.
The MOTW flag is designed to help protect users by notifying them that the file originates from an untrusted source, such as the internet. When a file bearing the MOTW flag is opened, Windows takes additional precautions to protect the user from executing potentially harmful content. In the case of 7-Zip, however, this safeguard is compromised during extraction, allowing attackers to bypass this mechanism and execute arbitrary code under the user’s privileges.
The exploit relies on user interaction, which means it cannot be fully automated. An attacker must either convince the user to open a malicious file from an archive or visit a website that serves a malicious archive. While this requirement limits the scope of potential attacks, the consequences of successful exploitation can be severe, especially for those who may not fully understand the risks of opening unknown or untrusted files.
From a technical perspective, the vulnerability lies in the way 7-Zip processes the MOTW flag during file extraction. It appears that when extracting files from an archive that is marked with the MOTW, 7-Zip does not properly pass the flag along to the extracted files. This oversight allows files to be extracted without the MOTW label, even though they originated from an untrusted source. The result is that malicious content can execute on the user’s system without triggering the expected security measures.
The CVSS score of 7.0 indicates that while this vulnerability is high-risk, it is not as dangerous as some other exploits that may allow remote code execution without user interaction. However, the potential for arbitrary code execution remains a serious concern. Attackers could use this flaw to install malware, gain unauthorized access to sensitive data, or perform other harmful actions on the compromised system.
Additionally, it is important to note that the vulnerability affects version 3.0 of 7-Zip, and there may be other versions of the software impacted by similar flaws. Users of 7-Zip should update to the latest version and exercise caution when extracting files from untrusted sources.
In terms of mitigation, the best approach is for users to ensure they are running the most recent version of 7-Zip, as updates typically address such security flaws. Beyond that, users should be cautious when handling compressed files from unknown or dubious sources and avoid clicking on links or opening files unless they are confident in their safety.
Another layer of protection comes from
In conclusion, while the 7-Zip Mark-of-the-Web bypass vulnerability is concerning, it is not without solutions. Staying up-to-date with the latest software versions, being cautious about opening files from untrusted sources, and leveraging built-in security features can help mitigate the risks. As always, awareness and vigilance are key in protecting against evolving cyber threats.
References:
Reported By: https://www.cve.org/CVERecord?id=CVE-2025-0411
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