CVE-2019-1789 in ClamAV
Summary
by MITRE
ClamAV versions prior to 0.101.2 are susceptible to a denial of service (DoS) vulnerability. An out-of-bounds heap read condition may occur when scanning PE files. An example is Windows EXE and DLL files that have been packed using Aspack as a result of inadequate bound-checking.
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Analysis
by VulDB Data Team • 06/30/2024
The vulnerability identified as CVE-2019-1789 represents a critical denial of service flaw affecting ClamAV versions prior to 01012. This issue stems from inadequate input validation during the scanning process of portable executable files, specifically impacting Windows EXE and DLL files that have been packed using Aspack compression utilities. The flaw manifests as an out-of-bounds heap read condition that occurs when ClamAV attempts to parse malformed PE file structures. This vulnerability falls under the Common Weakness Enumeration category CWE-125, which specifically addresses out-of-bounds read conditions in software applications. The security implications extend beyond simple service disruption as this DoS condition can be exploited by malicious actors to cause system instability and resource exhaustion. When ClamAV encounters a specially crafted packed PE file, the application fails to properly validate memory boundaries during file parsing operations, leading to unpredictable behavior and system crashes.
The operational impact of this vulnerability extends significantly within enterprise security environments where ClamAV serves as a primary antivirus scanning engine. Organizations utilizing ClamAV for network monitoring, email filtering, and endpoint protection face potential service interruptions when malicious actors deliberately craft PE files designed to trigger this heap read condition. The vulnerability affects not only individual system stability but also broader network security operations since ClamAV typically operates as a background service that continuously scans incoming files. Attackers can leverage this weakness by uploading or transmitting packed executables that will cause ClamAV processes to terminate unexpectedly, effectively creating a denial of service against the security infrastructure itself. This creates a dangerous scenario where the security tool becomes a vector for disruption rather than a protective mechanism.
Mitigation strategies for CVE-2019-1789 primarily focus on immediate software updates to ClamAV version 01012 or later, which includes proper boundary checking mechanisms for PE file parsing operations. System administrators should implement comprehensive patch management protocols to ensure all ClamAV installations receive the necessary security updates. Additionally, network administrators can deploy additional layers of protection by implementing file type filtering at network boundaries, preventing suspicious packed executables from reaching systems running ClamAV. The ATT&CK framework categorizes this vulnerability under the T1499.004 technique for "Endpoint Denial of Service" where adversaries target system resources to prevent legitimate use. Organizations should also consider implementing monitoring solutions that can detect unusual ClamAV process termination patterns, which would indicate potential exploitation attempts. Security teams should conduct regular vulnerability assessments to identify systems running outdated ClamAV versions and establish automated alerting mechanisms for any DoS attempts targeting the antivirus infrastructure.