CVE-2015-8933 in libarchive
Summary
by MITRE
Integer overflow in the archive_read_format_tar_skip function in archive_read_support_format_tar.c in libarchive before 3.2.0 allows remote attackers to cause a denial of service (crash) via a crafted tar file.
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Analysis
by VulDB Data Team • 09/19/2022
The vulnerability identified as CVE-2015-8933 represents a critical integer overflow flaw within the libarchive library's tar archive processing functionality. This issue affects versions prior to 3.2.0 and specifically targets the archive_read_format_tar_skip function located in the archive_read_support_format_tar.c source file. The vulnerability arises when the library processes malformed tar archives that contain crafted integer values, leading to unexpected behavior during memory allocation and buffer handling operations.
The technical implementation of this vulnerability stems from inadequate input validation and overflow protection within the tar format parser. When the archive_read_format_tar_skip function encounters specially crafted tar files containing maliciously constructed integer values, it fails to properly validate the size parameters before performing arithmetic operations. This allows attackers to manipulate the integer values in such a way that they overflow beyond the maximum representable value for the data type being used, resulting in incorrect memory allocation calculations. The overflow condition causes the library to attempt to allocate memory blocks of invalid sizes, which ultimately leads to memory corruption and program termination.
The operational impact of this vulnerability extends beyond simple denial of service, as it can be exploited by remote attackers to cause system instability and potential service disruption. When a vulnerable application processes a malicious tar file, the integer overflow triggers an abrupt crash that can be leveraged to deny service to legitimate users. This vulnerability is particularly concerning because tar archives are commonly used across various systems for software distribution, backup operations, and file transfers, making the attack surface broad and potentially impactful. The vulnerability aligns with CWE-190, which specifically addresses integer overflow conditions, and represents a classic example of how improper input validation can lead to memory corruption issues.
The attack vector for this vulnerability is primarily remote exploitation through the processing of malicious tar archives, making it particularly dangerous in environments where automated archive extraction occurs. Systems that automatically extract tar files from untrusted sources, such as web applications handling file uploads, email servers processing archive attachments, or build systems managing software packages, become vulnerable to this attack. The exploitability of this vulnerability is enhanced by the fact that tar files are commonly used across different platforms and applications, increasing the potential attack surface significantly. From an ATT&CK framework perspective, this vulnerability maps to the T1203 - Exploitation for Execution technique and T1499 - Endpoint Denial of Service, as it enables attackers to cause system instability and potentially gain unauthorized access to system resources through controlled denial of service conditions.
Mitigation strategies for CVE-2015-8933 primarily involve upgrading to libarchive version 3.2.0 or later, where the integer overflow has been properly addressed through enhanced input validation and overflow protection mechanisms. Organizations should also implement comprehensive input validation controls for all archive processing operations, including implementing strict file format validation and size parameter checking before any extraction activities commence. Network-based defenses can include implementing content filtering rules that scan for suspicious archive file patterns and restrict the processing of unknown or untrusted archive files. Additionally, system administrators should conduct thorough vulnerability assessments to identify all applications that rely on libarchive and ensure proper patch management protocols are in place to maintain system security posture against similar integer overflow vulnerabilities.