ESET Patches High-Severity Vulnerability in Windows Applications

Antivirus firm ESET on Monday announced patches for a local privilege escalation vulnerability impacting its Windows clients.

Tracked as CVE-2021-37852 and reported to ESET by the Zero Day Initiative (ZDI), the vulnerability is considered “high severity,” as it could allow an attacker to misuse the AMSI scanning feature.

“An attacker who is able to get SeImpersonatePrivilege can misuse the AMSI scanning feature to elevate to NT AUTHORITY\SYSTEM in some cases,” ESET explains in an advisory.

The cybersecurity firm also notes that, by default, the local Administrators group and the device’s Local Service accounts have access to SeImpersonatePrivilege. However, since these accounts are highly privileged, the impact of the bug is limited, ESET says.

The security error impacts multiple versions of ESET NOD32 Antivirus, Internet Security, Smart Security and Smart Security Premium, Endpoint Antivirus and Endpoint Security for Windows, Server Security and File Security for Windows Server, Server Security for Azure, Security for SharePoint Server, and Mail Security for IBM Domino and for Exchange Server.

[READ: SonicWall Patches Y2K22 Bug in Email Security, Firewall Products]

ESET released a series of patches for the vulnerability in December 2021, and then followed up with fixes for older versions of its Windows products in January 2022.

The company also notes that the vulnerability can be mitigated by heading to a product’s Advanced setup section and disabling the “Enable advanced scanning via AMSI” option. However, ESET recommends applying the workaround only if the upgrade to a patched product version is not possible.

“To the best of our knowledge, there are no existing exploits that take advantage of this vulnerability in the wild,” ESET also notes.

An advisory for CVE-2021-37852 has also been released by ZDI. ESET said it became aware of the flaw in November, but ZDI said the issue was reported to the vendor in June.

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Ionut Arghire is an international correspondent for SecurityWeek.

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