Pierluigi Paganini January 26, 2025

Cisco addressed a ClamAV denial-of-service (DoS) vulnerability, and experts warn of the availability of a proof-of-concept (PoC) exploit code.

Cisco has released security updates to address a ClamAV denial-of-service (DoS) vulnerability tracked as CVE-2025-20128. The Cisco PSIRT experts warn of the availability of a proof-of-concept (PoC) exploit code for this flaw.

The vulnerability resides in the Object Linking and Embedding 2 (OLE2) decryption routine of ClamAV. An unauthenticated, remote attacker could exploit the flaw to cause a denial of service (DoS) condition on a vulnerable device.

Cisco ClamAV (Clam AntiVirus) is an open-source antivirus engine designed to detect malware, viruses, and other malicious threats. It is widely used for email scanning, file scanning, and web security, particularly in Linux-based systems.

“This vulnerability is due to an integer underflow in a bounds check that allows for a heap buffer overflow read. An attacker could exploit this vulnerability by submitting a crafted file containing OLE2 content to be scanned by ClamAV on an affected device.” reads the advisory. “A successful exploit could allow the attacker to terminate the ClamAV scanning process, resulting in a DoS condition on the affected software.”

The Medium-impact vulnerability affects Linux, Mac, and Windows, potentially crashing scans and delaying or halting scanning operations.

The vulnerability impacts the following products:

The Cisco PSIRT is not aware of attacks in the wild exploiting this vulnerability.

Google OSS-Fuzz reported this vulnerability.

In February 2023, Cisco fixed a critical flaw, tracked as CVE-2023-20032 (CVSS score: 9.8), in ClamAV product. The vulnerability resides in the HFS+ file parser component, an attacker can trigger the issue to gain remote code execution on vulnerable devices or trigger a DoS condition.

Tracked as CVE-2023-20032 (CVSS score: 9.8), the issue relates to a case of remote code execution residing in the HFS+ file parser.

The flaw affects versions 1.0.0 and earlier, 0.105.1 and earlier, and 0.103.7 and earlier. The company acknowledged Simon Scannell from Google for reporting this issue.

The vulnerability is a buffer overflow issue affecting the ClamAV scanning library, it is due to a missing buffer size check.

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Pierluigi Paganini

(SecurityAffairs – hacking, ClamAV)