CVE-2007-0898 in ClamAV
Summary
by MITRE
Directory traversal vulnerability in clamd in Clam AntiVirus ClamAV before 0.90 allows remote attackers to overwrite arbitrary files via a .. (dot dot) in the id MIME header parameter in a multi-part message.
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Analysis
by VulDB Data Team • 07/13/2021
The vulnerability described in CVE-2007-0898 represents a critical directory traversal flaw within the clamd daemon component of Clam AntiVirus ClamAV version 0.90 and earlier. This security weakness specifically affects the email scanning functionality of the antivirus system when processing multi-part email messages. The vulnerability stems from insufficient input validation in the handling of MIME header parameters, particularly the id parameter within the MIME header structure. Attackers can exploit this flaw by crafting malicious email messages containing specially formatted .. (dot dot) sequences within the id MIME header parameter, which allows them to manipulate file paths and potentially overwrite arbitrary files on the system where clamd is running.
The technical implementation of this vulnerability involves the improper handling of directory navigation sequences during the processing of email attachments and headers. When clamd processes multi-part email messages, it parses the MIME headers to extract various parameters including the id field. The flaw occurs because the application does not adequately sanitize or validate the id parameter before using it in file system operations. This allows attackers to inject directory traversal sequences that can navigate outside the intended directory structure and access or modify files that should otherwise be protected. The vulnerability specifically targets the path resolution mechanism within the email scanning pipeline, where the system attempts to store temporary files or process attachments based on the parsed MIME header information.
The operational impact of this vulnerability extends beyond simple file overwrites to potentially enable more severe attack vectors including privilege escalation, system compromise, and denial of service conditions. Remote attackers who can send malicious email messages to systems running vulnerable clamd daemons can leverage this weakness to overwrite critical system files, configuration files, or even executable components that could lead to complete system compromise. The attack requires no special privileges to initiate, making it particularly dangerous as it can be exploited through standard email communication channels. This vulnerability directly impacts organizations that rely on ClamAV for email security scanning, as it undermines the integrity of the email filtering process and creates potential entry points for attackers to gain unauthorized access to email servers and associated systems.
Mitigation strategies for this vulnerability should focus on immediate patch application to upgrade to ClamAV version 0.90 or later, which contains the necessary fixes for the directory traversal issue. Organizations should also implement network-level restrictions to limit email traffic to systems running clamd, particularly in environments where the daemon is exposed to untrusted email sources. Additional protective measures include configuring clamd to run with minimal privileges and restricted file system access, implementing proper input validation at network boundaries, and monitoring for unusual file system access patterns that might indicate exploitation attempts. From a defensive perspective, this vulnerability aligns with CWE-22 Directory Traversal and follows attack patterns documented in the ATT&CK framework under T1059 Command and Scripting Interpreter and T1078 Valid Accounts, as it enables attackers to manipulate system files through legitimate email processing functions while potentially leveraging compromised accounts to maintain persistence. The vulnerability highlights the importance of proper input validation in security applications and demonstrates how seemingly benign email processing functionality can become a critical attack surface when inadequate sanitization measures are implemented.