CVE-2016-1371 in ClamAV
Summary
by MITRE
ClamAV (aka Clam AntiVirus) before 0.99.2 allows remote attackers to cause a denial of service (application crash) via a crafted mew packer executable.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 09/21/2022
ClamAV represents a widely deployed open-source antivirus engine that serves as the foundation for numerous security solutions across enterprise and endpoint environments. The vulnerability identified as CVE-2016-1371 specifically targets the mew packer executable handling functionality within ClamAV versions prior to 0.99.2. This flaw manifests as a denial of service condition that can be triggered remotely by adversaries who craft malicious mew packer executables designed to exploit the underlying parsing mechanisms. The mew packer is a legitimate compression format used by certain malware families, but when processed by vulnerable ClamAV versions, it triggers an application crash that terminates the scanning process.
The technical nature of this vulnerability resides in improper input validation and memory management within the ClamAV engine's parser for mew packer format files. When ClamAV encounters a malformed or specially crafted mew packer executable, the parser fails to properly handle the unexpected data structures, leading to memory corruption or invalid pointer dereferences that ultimately cause the application to crash. This behavior aligns with common software security weaknesses categorized under CWE-121, which addresses heap-based buffer overflow conditions, and CWE-125, which covers out-of-bounds read vulnerabilities. The vulnerability demonstrates characteristics consistent with the attack pattern described in the MITRE ATT&CK framework under T1499.004 for network denial of service attacks, where adversaries leverage software flaws to disrupt system availability.
The operational impact of this vulnerability extends beyond simple service interruption as it affects the reliability and trustworthiness of antivirus scanning operations. Organizations relying on ClamAV for endpoint protection face potential exposure to continued malware threats during the brief window when the scanning service is unavailable. The remote exploitability means that adversaries can trigger this condition without requiring local access to systems, making it particularly concerning for networked environments where ClamAV is deployed as a network-based scanner or integrated into larger security infrastructure. Security operations teams may experience increased false positive rates or scanning failures that could mask actual malware infections, undermining the effectiveness of their defensive posture.
Mitigation strategies for CVE-2016-1371 primarily involve immediate deployment of ClamAV version 0.99.2 or later, which includes patches addressing the mew packer parsing vulnerability. Organizations should also implement network segmentation and monitoring to detect anomalous scanning behavior that might indicate exploitation attempts. Additional defensive measures include configuring ClamAV to limit resource consumption during scanning operations and implementing redundant scanning mechanisms to maintain protection coverage during potential service disruptions. The vulnerability highlights the importance of regular security patch management and the need for comprehensive testing of security software updates before deployment in production environments. Security professionals should also consider implementing behavioral monitoring solutions that can detect and alert on unusual application crash patterns that might indicate exploitation of similar parsing vulnerabilities in antivirus software.