CVE-2005-0133 in ClamAV
Summary
by MITRE
ClamAV 0.80 and earlier allows remote attackers to cause a denial of service (clamd daemon crash) via a ZIP file with malformed headers.
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Analysis
by VulDB Data Team • 07/01/2021
The vulnerability identified as CVE-2005-0133 represents a critical denial of service weakness in ClamAV versions 0.80 and earlier, specifically affecting the clamd daemon service. This flaw manifests when the daemon processes specially crafted ZIP archive files containing malformed headers, leading to unexpected termination of the scanning service. The issue stems from insufficient input validation within the archive parsing component of ClamAV, which fails to properly handle malformed ZIP file structures during the scanning process. The vulnerability directly impacts the availability of security services by causing the clamd daemon to crash and restart, potentially leaving systems unprotected during the recovery period.
The technical implementation of this vulnerability involves the improper handling of ZIP file header structures within ClamAV's decompression and analysis routines. When the clamd daemon encounters a ZIP file with malformed headers, the parsing logic does not adequately validate the header fields or enforce proper boundary checks. This lack of input sanitization creates a condition where malformed data can trigger memory access violations or stack corruption within the daemon process, ultimately resulting in an unhandled exception that terminates the service. The vulnerability operates at the application layer and requires no authentication or specialized privileges to exploit, making it particularly dangerous in networked environments where ClamAV may process files from untrusted sources.
From an operational impact perspective, this vulnerability presents significant risks to organizations relying on ClamAV for email filtering, file scanning, or endpoint protection services. The denial of service condition can be exploited by remote attackers to disrupt security operations, potentially allowing malicious payloads to bypass detection during the daemon restart period. In enterprise environments where ClamAV serves as a core security component, such an attack could lead to extended periods of reduced security coverage, creating windows of opportunity for other attacks. The vulnerability also demonstrates poor defensive programming practices that could indicate similar issues in other parts of the codebase, suggesting a broader need for input validation improvements.
The weakness aligns with CWE-129, which addresses improper validation of input boundaries, and represents a classic example of inadequate error handling in security software. This vulnerability also maps to ATT&CK technique T1499.004, which covers the use of denial of service attacks to disrupt security services. Organizations should implement immediate mitigations including upgrading to ClamAV version 0.81 or later where this vulnerability has been addressed, implementing network segmentation to limit exposure, and deploying additional monitoring to detect daemon restart events. Additional protective measures include configuring file type filtering to limit ZIP file processing, implementing rate limiting for file scanning requests, and ensuring that the clamd daemon runs with minimal privileges to limit potential impact from successful exploitation attempts.