CVE-2017-11125 in xar
Summary
by MITRE
libxar.so in xar 1.6.1 has a NULL pointer dereference in the xar_get_path function in util.c.
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Analysis
by VulDB Data Team • 12/12/2022
The vulnerability identified as CVE-2017-11125 resides within the libxar.so library component of the xar archive utility version 1.6.1. This flaw manifests as a NULL pointer dereference occurring within the xar_get_path function located in the util.c source file. The xar utility serves as a command-line tool for creating and manipulating archive files, particularly those using the eXtensible Archive Format. The affected library is commonly utilized in various operating systems and applications that require archive handling capabilities, making this vulnerability potentially widespread in scope.
The technical nature of this vulnerability stems from improper input validation and error handling within the xar_get_path function. When processing certain malformed or unexpected archive structures, the function fails to properly check for NULL pointer conditions before attempting to dereference a pointer variable. This NULL pointer dereference represents a classic software defect that can lead to application crashes and potential denial of service conditions. The flaw specifically occurs during the path extraction process when the library encounters archive entries that do not conform to expected structural patterns, causing the software to attempt operations on uninitialized or invalid memory references.
The operational impact of this vulnerability extends beyond simple application instability, as it can be exploited to cause system-wide denial of service scenarios. An attacker who can control the input to the xar utility could potentially craft malicious archive files that trigger this NULL pointer dereference when processed by applications relying on libxar.so. This vulnerability affects systems where xar functionality is utilized, including various Unix-like operating systems and applications that incorporate the xar library for archive handling. The exploitation of this flaw could result in complete application termination, system resource exhaustion, or in some cases, could potentially be leveraged as part of a broader attack chain targeting system stability and availability.
Security professionals should note that this vulnerability aligns with CWE-476, which specifically addresses NULL pointer dereference conditions in software implementations. The flaw also demonstrates characteristics consistent with ATT&CK technique T1499.004, which involves network denial of service attacks through resource exhaustion or application instability. Mitigation strategies should include immediate patching of affected systems to upgrade to xar versions that address this NULL pointer dereference issue. System administrators should also implement input validation measures and consider sandboxing archive processing operations to limit potential impact. Additionally, monitoring for unusual application termination patterns or resource consumption spikes could help detect exploitation attempts targeting this vulnerability. Organizations relying on xar functionality should conduct comprehensive vulnerability assessments to identify all systems and applications that utilize libxar.so and ensure proper patch management protocols are in place to address this and related archive processing vulnerabilities.