CVE-2004-0270 in ClamAV
Summary
by MITRE
libclamav in Clam AntiVirus 0.65 allows remote attackers to cause a denial of service (crash) via a uuencoded e-mail message with an invalid line length (e.g., a lowercase character), which causes an assert error in clamd that terminates the calling program.
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Analysis
by VulDB Data Team • 11/11/2024
The vulnerability identified as CVE-2004-0270 resides within the libclamav library component of Clam AntiVirus version 0.65, representing a critical denial of service weakness that can be exploited remotely. This flaw specifically targets the email scanning functionality of the antivirus system when processing uuencoded email messages, creating a scenario where malicious actors can deliberately trigger system instability through carefully crafted input. The vulnerability demonstrates a fundamental issue in input validation and error handling mechanisms within the ClamAV scanning engine, where the system fails to properly process malformed data sequences that should be gracefully handled rather than causing system termination.
The technical root cause of this vulnerability stems from an insufficient validation of line length parameters within uuencoded email message processing. When clamd encounters a uuencoded message containing an invalid line length specification, such as the presence of lowercase characters where uppercase letters are expected, the system's internal assertion mechanism triggers an error condition that results in immediate program termination. This represents a classic buffer overflow or assertion failure vulnerability where the program's defensive programming logic is bypassed by malformed input, causing the daemon to crash and cease operations. The vulnerability aligns with CWE-682, which categorizes issues related to incorrect arithmetic operations or invalid input handling that can lead to program termination or unexpected behavior.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be leveraged by remote attackers to systematically disable antivirus protection services across affected systems. When clamd crashes due to this assertion error, it creates a window of vulnerability where the system becomes temporarily unprotected against malware threats, potentially allowing malicious payloads to bypass security controls. The attack vector is particularly concerning because email-based attacks are common and difficult to prevent entirely, making this vulnerability a significant risk for organizations relying on ClamAV for email security filtering. The vulnerability also represents a potential pathway for attackers to establish persistence or conduct further reconnaissance, as the service disruption may trigger alerts or logs that could be exploited by advanced threat actors.
Organizations affected by this vulnerability should implement immediate mitigations including updating to patched versions of Clam AntiVirus, implementing network-level filtering to prevent malformed email traffic, and establishing monitoring procedures to detect service disruptions. The remediation strategy should also include configuring redundant antivirus services to maintain protection during patch deployment and implementing proper input sanitization measures at network boundaries. From an operational security perspective, this vulnerability highlights the importance of robust error handling and defensive programming practices that prevent assertion failures from terminating critical security services. The ATT&CK framework categorizes this type of vulnerability under T1499.004, which covers network denial of service attacks, while the underlying technical implementation issues align with T1595.001, focusing on reconnaissance techniques that identify system weaknesses through controlled input testing.