CVE-2006-1989 in ClamAV
Summary
by MITRE
Buffer overflow in the get_database function in the HTTP client in Freshclam in ClamAV 0.80 to 0.88.1 might allow remote web servers to execute arbitrary code via long HTTP headers.
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Analysis
by VulDB Data Team • 11/24/2024
The vulnerability identified as CVE-2006-1989 represents a critical buffer overflow condition within the Freshclam component of ClamAV software versions ranging from 0.80 through 0.88.1. This flaw exists in the HTTP client implementation specifically within the get_database function, which processes HTTP responses from remote web servers. The buffer overflow occurs when the client receives HTTP headers that exceed the allocated buffer space, creating an exploitable condition that can be leveraged by remote attackers to execute arbitrary code on systems running vulnerable versions of ClamAV.
The technical mechanism of this vulnerability stems from inadequate input validation and buffer management within the HTTP client library used by Freshclam. When the get_database function processes HTTP responses, it fails to properly check the length of incoming header data before copying it into fixed-size buffers. This classic buffer overflow scenario allows an attacker controlling a remote web server to craft malicious HTTP responses containing excessively long headers that overwrite adjacent memory regions. The vulnerability manifests as a stack-based buffer overflow, where the overflowed data can overwrite return addresses and other critical program state information, enabling arbitrary code execution with the privileges of the Freshclam process.
The operational impact of CVE-2006-1989 extends beyond simple code execution, as it represents a significant threat to system integrity and availability within antivirus deployment environments. Since Freshclam operates as the component responsible for downloading virus definition updates from remote servers, attackers can exploit this vulnerability during the update process without requiring direct user interaction or elevated privileges. The attack surface is particularly concerning because Freshclam typically runs with elevated privileges to maintain antivirus definitions, making successful exploitation potentially devastating for system security. Organizations relying on ClamAV for endpoint protection face substantial risk of complete system compromise when this vulnerability remains unpatched.
This vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and demonstrates characteristics consistent with ATT&CK technique T1059.007 for command and scripting interpreter execution. The flaw also corresponds to CWE-787, representing out-of-bounds write conditions that occur when data is written past the end of a buffer. Mitigation strategies should include immediate patching of ClamAV to versions 0.89 or later, where the buffer overflow has been addressed through proper input validation and buffer size enforcement. Network-level defenses such as intrusion detection systems should monitor for suspicious HTTP header patterns that might indicate exploitation attempts, while system administrators should consider implementing network segmentation to limit exposure of vulnerable Freshclam instances to untrusted networks. Additionally, organizations should conduct thorough vulnerability assessments to identify all systems running affected ClamAV versions and establish automated patch management procedures to prevent similar vulnerabilities from accumulating in their security infrastructure.