CVE-2015-8928 in libarchive
Summary
by MITRE
The process_add_entry function in archive_read_support_format_mtree.c in libarchive before 3.2.0 allows remote attackers to cause a denial of service (out-of-bounds read) via a crafted mtree file.
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Analysis
by VulDB Data Team • 09/19/2022
The vulnerability identified as CVE-2015-8928 represents a critical out-of-bounds read flaw within the libarchive library's mtree format processing functionality. This issue specifically affects the process_add_entry function located in the archive_read_support_format_mtree.c source file, which is part of the broader libarchive software suite used extensively for handling various archive formats including mtree files. The vulnerability manifests when the library processes maliciously crafted mtree files, potentially leading to system instability and denial of service conditions that can be exploited remotely by attackers.
The technical nature of this flaw stems from inadequate input validation and boundary checking within the mtree parsing code. When the process_add_entry function encounters malformed mtree entries, it fails to properly validate array indices or buffer limits before accessing memory locations. This allows an attacker to construct a specially crafted mtree file that causes the library to read memory beyond its allocated boundaries, resulting in unpredictable behavior and system crashes. The vulnerability is classified as a memory safety issue that aligns with CWE-129, which addresses improper validation of array indices, and represents a classic example of buffer over-read conditions that can be exploited for denial of service attacks.
From an operational impact perspective, this vulnerability poses significant risks to systems that rely on libarchive for processing untrusted archive content, particularly in network services, file processing applications, and automated systems that handle user-uploaded files. The remote exploitation capability means that attackers can trigger the vulnerability without requiring local access, making it particularly dangerous in web applications, file servers, and content delivery systems. The out-of-bounds read can result in application crashes, memory corruption, or potentially even information disclosure depending on the specific memory access patterns and system configurations. This vulnerability directly impacts the availability and stability of services that depend on libarchive functionality.
Mitigation strategies for CVE-2015-8928 primarily involve upgrading to libarchive version 3.2.0 or later, which includes patches that address the boundary checking issues in the mtree processing code. System administrators should prioritize patching affected systems, particularly those handling untrusted archive content or serving as file processing endpoints. Additional protective measures include implementing proper input validation, using sandboxing techniques, and deploying network monitoring to detect exploitation attempts. The vulnerability demonstrates the importance of robust input validation in archive processing libraries and aligns with ATT&CK technique T1203, which covers exploitation of software vulnerabilities for denial of service. Organizations should also consider implementing least privilege principles for applications that process archive files and establish monitoring procedures to detect anomalous file processing behavior that might indicate exploitation attempts.