CVE-2007-0899 in ClamAV
Summary
by MITRE
There is a possible heap overflow in libclamav/fsg.c before 0.100.0.
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Analysis
by VulDB Data Team • 02/05/2024
The vulnerability identified as CVE-2007-0899 represents a critical heap overflow condition within the ClamAV antivirus engine's file system guard component, specifically in the libclamav/fsg.c source file. This flaw existed in versions prior to 0.100.0 and demonstrates a classic memory corruption vulnerability that can be exploited to compromise system integrity. The issue stems from inadequate input validation and memory management practices within the decompression and file parsing routines that handle various file formats, particularly those associated with packed or compressed files that utilize the FSG (File System Guard) compression algorithm. The vulnerability occurs when the application processes maliciously crafted files that trigger buffer overflow conditions during decompression operations.
The technical implementation of this heap overflow involves improper bounds checking during memory allocation and data copying operations within the FSG decompression logic. When ClamAV encounters a specially crafted file that exploits this vulnerability, the application fails to properly validate the size of incoming data before copying it into allocated heap memory regions. This results in memory corruption that can overwrite adjacent heap chunks, potentially leading to arbitrary code execution or application crashes. The vulnerability aligns with CWE-122, which describes improper restriction of operations within a memory buffer, and specifically manifests as a heap-based buffer overflow that violates fundamental memory safety principles. The flaw operates at the intersection of file format parsing and memory management, making it particularly dangerous in antivirus contexts where applications process untrusted input from multiple sources.
The operational impact of CVE-2007-0899 extends beyond simple application instability, as it provides potential attack vectors for remote code execution in scenarios where ClamAV is deployed in network-based security solutions or when processing files from untrusted sources. Attackers can craft malicious files that, when scanned by vulnerable ClamAV versions, trigger the heap overflow condition and potentially execute arbitrary code with the privileges of the scanning process. This vulnerability is particularly concerning in enterprise environments where ClamAV serves as a primary malware detection mechanism, as successful exploitation could allow attackers to bypass security controls or compromise entire systems. The attack surface is broad since ClamAV is widely deployed across various platforms and integrated into numerous security solutions, making this vulnerability a significant concern for organizations maintaining antivirus protection systems.
Mitigation strategies for this vulnerability require immediate version updates to ClamAV 0.100.0 or later, which contain fixed implementations of the FSG decompression routines with proper bounds checking and memory management. Organizations should also implement additional security measures such as restricting file scanning to trusted sources, deploying network segmentation to limit potential attack vectors, and monitoring for anomalous scanning behavior that might indicate exploitation attempts. The remediation process should include comprehensive testing of updated ClamAV versions to ensure compatibility with existing security infrastructure while maintaining effective malware detection capabilities. Security professionals should also consider implementing behavioral monitoring solutions that can detect unusual memory allocation patterns or heap corruption indicators that might suggest exploitation attempts, aligning with ATT&CK technique T1059.007 for command and scripting interpreter execution and T1070.004 for indicator removal on host. Regular vulnerability assessments and security audits should be conducted to identify similar memory corruption vulnerabilities in other security tools and applications within the organization's infrastructure.