Zero-Day Vulnerability Discovered in 7-Zip Amid Ongoing Conflict in Ukraine
In recent developments, security researchers have identified a zero-day vulnerability in the widely used 7-Zip archiving application, which has reportedly been exploited in connection with Russia’s military operations in Ukraine. The vulnerability poses a significant security risk, as it allows malicious actors to evade established Windows security measures designed to restrict the execution of files downloaded from the Internet.
This particular flaw enabled a Russian cybercrime group to circumvent the Mark of the Web (MotW) protective mechanism—a safety feature intended to safeguard users by tagging downloaded files with a "Zone.Identifier" marker. This tag is implemented through NTFS Alternate Data Streams, specifically as a ZoneID=3, triggering Windows Defender SmartScreen to impose additional security checks on these files. The MotW designation limits the circumstances under which downloaded files can be executed, thereby reducing the risk of malicious software running on users’ systems.
The exploitation of this vulnerability occurred through a double-archive manipulation technique. Cybercriminals were able to embed an executable file within an archive and then further encapsulate that archive within another. While the outer archive retained the MotW protection tag, the inner one did not, effectively allowing harmful files to execute without the typical safeguards. The vulnerability, officially tracked as CVE-2025-0411, was rectified in version 24.09 of 7-Zip, released in late November.
The root cause of CVE-2025-0411 stems from the failure of versions prior to 24.09 of 7-Zip to adequately propagate MotW protections to nested archives. This oversight enables threat actors to create malicious archives that bypass the intended security protocols, exposing users to significant risks. Peter Girnus, a researcher at Trend Micro—the firm that uncovered the flaw—highlighted this issue, indicating that it leaves Windows users open to attacks involving crafted archives containing harmful scripts or executables.
The targeted victims seem to include organizations with an impact on national security or strategic interests, especially amid the ongoing hostilities in Ukraine. As the geopolitical landscape continues to evolve, the cybersecurity implications of these vulnerabilities warrant serious attention from business owners who may be unwittingly exposed.
In terms of attack methodology, this situation aligns with various tactics outlined in the MITRE ATT&CK framework. Specifically, elements of initial access may have been leveraged by utilizing the zero-day vulnerability to deliver malicious payloads. Additionally, techniques such as privilege escalation and persistence could have facilitated ongoing access to compromised systems.
As businesses confront the realities of cyber threats amplified by global conflict, understanding vulnerabilities like that found in 7-Zip is essential. Organizations are encouraged to promptly update their software to the latest versions and maintain a rigorous approach to cyber hygiene, ensuring that all security measures are effectively implemented. The lessons learned from this incident emphasize the importance of continuous vigilance in safeguarding digital assets.
