CVE-2015-2222 in Clam
Summary
by MITRE
ClamAV before 0.98.7 allows remote attackers to cause a denial of service (crash) via a crafted petite packed file.
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Analysis
by VulDB Data Team • 05/10/2022
ClamAV is a widely deployed open-source antivirus engine designed to detect trojans, viruses, malware and other malicious threats in email and file transfers. The vulnerability identified as CVE-2015-2222 affects ClamAV versions prior to 0.98.7 and represents a denial of service flaw that can be exploited remotely through specifically crafted petite packed files. This vulnerability falls under the CWE-119 category of "Improper Access to Memory" and aligns with ATT&CK technique T1499.004 for network denial of service attacks. The petite file format is a compression method that reduces executable file sizes while maintaining functionality, making it a common target for malware authors seeking to obfuscate their payloads.
The technical flaw occurs within ClamAV's file unpacking and analysis routines when processing malformed petite packed files. When the antivirus engine encounters a specially crafted petite packed file, its decompression logic fails to properly validate input data structures, leading to memory corruption that ultimately results in a crash of the ClamAV daemon or scanning process. This memory corruption stems from inadequate bounds checking and improper handling of compressed data within the unpacking algorithm. The vulnerability is particularly concerning because it can be triggered through standard file scanning operations without requiring special privileges or authentication, making it easily exploitable in networked environments where ClamAV is deployed for automated threat detection.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise security operations within organizations relying on ClamAV for threat detection. When an attacker successfully triggers this denial of service condition, it can cause the antivirus scanning service to crash repeatedly, leading to gaps in malware detection coverage and potential false security assurances. In enterprise environments where ClamAV is integrated into email filtering systems, network security appliances, or file integrity monitoring solutions, such a crash could result in significant security gaps and operational downtime. The vulnerability also represents a potential reconnaissance tool for threat actors who might use it to identify systems running vulnerable versions of ClamAV, potentially leading to more sophisticated attacks targeting other weaknesses in the same infrastructure.
Organizations should immediately upgrade to ClamAV version 0.98.7 or later to mitigate this vulnerability, as this release includes proper input validation and memory handling fixes for petite packed file processing. System administrators should also implement monitoring solutions to detect unusual crash patterns in antivirus services and consider deploying intrusion detection systems that can identify attempts to exploit this specific vulnerability. Additional defensive measures include configuring ClamAV to use more restrictive file type handling, implementing file extension filtering, and ensuring that automated scanning processes include proper error handling and recovery mechanisms. The vulnerability demonstrates the importance of proper input validation in security software and highlights how seemingly benign file format processing can create critical security weaknesses when not properly secured against malformed inputs.