CVE-2007-4195 in The Sleuth Kit
Summary
by MITRE
Use-after-free vulnerability in ext2fs.c in Brian Carrier The Sleuth Kit (TSK) before 2.09 allows user-assisted remote attackers to cause a denial of service (application crash) and prevent examination of certain ext2fs files via a malformed ext2fs image.
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Analysis
by VulDB Data Team • 10/27/2017
The CVE-2007-4195 vulnerability represents a critical use-after-free condition within The Sleuth Kit library, specifically in the ext2fs.c component that processes ext2 filesystem images. This vulnerability affects versions of TSK prior to 2.09 and demonstrates a classic memory safety issue that has significant implications for digital forensics operations. The flaw occurs when the application processes malformed ext2 filesystem images, creating a scenario where memory previously allocated to a data structure is accessed after it has been freed, leading to unpredictable behavior and potential system instability.
The technical implementation of this vulnerability stems from inadequate input validation and memory management practices within the ext2 filesystem parsing code. When TSK encounters a malformed ext2 filesystem image, the ext2fs.c module fails to properly handle the corrupted data structures, resulting in a situation where a pointer references freed memory. This condition typically occurs during the processing of filesystem metadata where the application allocates memory for internal data structures, processes the corrupted data, and subsequently frees the memory without proper nullification. Attackers can exploit this by crafting malicious ext2 filesystem images that trigger the specific code path leading to the use-after-free condition, effectively allowing them to manipulate the application's memory state.
The operational impact of this vulnerability extends beyond simple denial of service, as it fundamentally compromises the reliability of digital forensics investigations. When an application crash occurs during forensic examination, investigators lose access to critical evidence and may be unable to complete their analysis of potentially compromised systems. This vulnerability particularly affects law enforcement agencies, cybersecurity professionals, and forensic analysts who rely on TSK for examining ext2 filesystems, as it creates a window of opportunity for attackers to disrupt investigations or evade detection. The remote nature of the attack means that an adversary could potentially exploit this vulnerability without physical access to the target system, making it particularly dangerous in networked environments where forensic tools may be processing images received from external sources.
Mitigation strategies for CVE-2007-4195 require immediate patching of affected TSK installations to version 2.09 or later, which contains the necessary memory management fixes. Organizations should implement strict input validation procedures for all filesystem images processed by forensic tools, including preliminary analysis of image integrity before full processing. The vulnerability aligns with CWE-416, which describes the use of freed memory condition, and represents a common pattern in forensic software that fails to properly handle malformed input data. From an ATT&CK framework perspective, this vulnerability could be categorized under defensive evasion techniques, where adversaries attempt to disrupt forensic analysis capabilities through application-level attacks. Additionally, implementing proper memory debugging tools and static analysis of forensic software can help identify similar vulnerabilities in other components of the digital forensics toolchain, ensuring comprehensive protection against similar use-after-free conditions that could compromise forensic integrity and investigative capabilities.