A critical zero-day vulnerability has been identified in WinRAR, a widely used file compression tool, which cybercriminals are actively exploiting through sophisticated phishing campaigns to distribute RomCom malware. This flaw, designated as CVE-2025-8088, poses a significant security threat, enabling attackers to execute arbitrary code on victims’ systems via malicious archive files.
Understanding the Vulnerability
The vulnerability stems from a directory traversal weakness affecting Windows versions of WinRAR, including RAR, UnRAR, portable UnRAR source code, and UnRAR.dll components. When users extract files from specially crafted archives, the malicious payload can manipulate the extraction process to place files in unintended system locations, bypassing user-specified destination paths. This technique allows attackers to place executable files in sensitive system directories, potentially achieving privilege escalation and persistence mechanisms on compromised systems.
ESET security researchers Anton Cherepanov, Peter Košinár, and Peter Strýček discovered this critical flaw and confirmed its active exploitation in real-world attacks. The exploitation methodology involves crafting archives with manipulated directory structures that exploit the file path validation bypass. When victims extract these archives using vulnerable WinRAR versions, the malware automatically executes without requiring additional user interaction, making it particularly dangerous for unsuspecting users.
RomCom Malware Campaign
Cybercriminals have weaponized this zero-day vulnerability specifically to distribute RomCom malware through targeted phishing campaigns. The attack chain typically begins with social engineering tactics, where victims receive seemingly legitimate compressed files via email attachments or malicious download links. These archives contain the RomCom payload disguised as legitimate documents or software installers.
The RomCom malware campaign demonstrates sophisticated Advanced Persistent Threat (APT)-style tactics, utilizing the WinRAR vulnerability as an initial access vector. Once successfully deployed, the malware establishes command and control communications, enabling threat actors to perform reconnaissance, lateral movement, and data exfiltration activities within compromised networks.
Security analysts note that this attack vector is particularly effective because compressed archives are commonly shared in business environments, making detection challenging for traditional security solutions that may not thoroughly inspect archive contents before extraction.
Risk Factors and Affected Products
The following table summarizes the risk factors associated with this vulnerability:
| Risk Factors | Details |
|————————|——————————————————————————————-|
| Affected Products | – Windows versions of WinRAR
– Windows versions of RAR
– Windows versions of UnRAR
– Portable UnRAR source code
– UnRAR.dll |
| Impact | Arbitrary code execution |
| Exploit Prerequisites | – User must extract a specially crafted malicious archive
– Social engineering (phishing emails/malicious downloads)
– No additional user interaction required after extraction |
| CVSS 3.1 Score | 8.4 (High) |
Mitigation and Recommendations
To mitigate the risks associated with CVE-2025-8088, users are strongly advised to update to WinRAR version 7.13 immediately. Since WinRAR does not include an auto-update feature, it is essential to manually download and install the latest version from the official WinRAR website.
Additionally, organizations should implement the following security measures:
– User Education: Train employees to recognize phishing attempts and avoid opening unsolicited email attachments.
– Email Filtering: Deploy advanced email filtering solutions to detect and block malicious attachments.
– Endpoint Protection: Utilize endpoint detection and response (EDR) solutions to monitor and respond to suspicious activities.
– Regular Software Updates: Ensure all software applications are regularly updated to their latest versions to patch known vulnerabilities.
By taking these proactive steps, individuals and organizations can significantly reduce the risk of falling victim to attacks exploiting this WinRAR vulnerability.
