CVE-2007-3645 in libarchive
Summary
by MITRE
archive_read_support_format_tar.c in libarchive before 2.2.4 allows user-assisted remote attackers to cause a denial of service (crash) via (1) an end-of-file condition within a tar header that follows a pax extension header or (2) a malformed pax extension header in an (a) PAX or a (b) TAR archive, which results in a NULL pointer dereference, a different issue than CVE-2007-3644.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 07/23/2019
The vulnerability described in CVE-2007-3645 affects the libarchive library version 2.2.3 and earlier, specifically within the archive_read_support_format_tar.c module responsible for processing tar archive formats. This flaw represents a critical security issue that can be exploited by remote attackers with minimal privileges to disrupt system availability through carefully crafted archive files. The vulnerability manifests when the library processes tar archives containing malformed or specially constructed pax extension headers, which can lead to unpredictable system behavior and complete service disruption.
The technical implementation of this vulnerability involves two distinct attack vectors that both result in NULL pointer dereference conditions within the tar parsing logic. The first vector occurs when an end-of-file condition appears immediately after a pax extension header within a tar archive structure, while the second vector involves malformed pax extension headers present in either PAX or standard TAR archives. These conditions cause the libarchive library to attempt to access memory locations that have not been properly initialized or allocated, leading to immediate program termination and system crash. The flaw is classified as a memory safety issue that directly violates standard software security practices and can be categorized under CWE-476 which describes NULL Pointer Dereference conditions.
From an operational perspective, this vulnerability poses significant risks to systems that rely on libarchive for processing user-provided archive files, including web servers, file sharing platforms, and automated backup systems. The remote exploitation capability means that attackers can trigger the denial of service condition without requiring local system access, making it particularly dangerous in networked environments. Systems that process untrusted archive data, such as email servers handling attachment processing or content delivery networks serving downloadable files, become prime targets for this type of attack. The vulnerability's impact extends beyond simple service disruption to potentially enable more sophisticated attack chains when combined with other weaknesses in the system architecture.
Security professionals should consider this vulnerability in the context of the broader ATT&CK framework, particularly under the T1499 category related to Network Denial of Service, and T1078 which addresses valid accounts and legitimate credentials. The vulnerability demonstrates how seemingly benign file processing functionality can become a vector for system compromise, highlighting the importance of proper input validation and memory management in security-critical libraries. Organizations should prioritize immediate patching of affected systems, as the vulnerability affects multiple versions of the libarchive library that are commonly deployed across enterprise environments. Additionally, implementing network segmentation and access controls around systems that process untrusted archive files can provide additional defense-in-depth measures against exploitation attempts. The issue also underscores the necessity of regular security assessments and vulnerability management processes to identify and remediate similar flaws before they can be exploited by malicious actors in the wild.