CVE-2016-1253 in wheezy
Summary
by MITRE
The most package in Debian wheezy before 5.0.0a-2.2, in Debian jessie before 5.0.0a-2.3+deb8u1, and in Debian unstable before 5.0.0a-3 allows remote attackers to execute arbitrary commands via shell metacharacters in the name of an LZMA-compressed file.
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Analysis
by VulDB Data Team • 01/23/2020
The vulnerability identified as CVE-2016-1253 affects the most package in Debian distributions, representing a critical command injection flaw that enables remote attackers to execute arbitrary code on affected systems. This vulnerability specifically targets the handling of LZMA-compressed files within the package management system, where insufficient input validation allows maliciously crafted file names to contain shell metacharacters that get interpreted during decompression operations. The issue exists across multiple Debian releases including wheezy, jessie, and unstable versions, with specific version thresholds indicating the patch levels required to mitigate the vulnerability. The most package is commonly used for managing compressed files and archives, making this a significant security concern for systems that process untrusted compressed content.
The technical flaw stems from improper sanitization of file names during LZMA decompression operations, where the software directly incorporates user-supplied file names into shell commands without adequate escaping or validation. When an LZMA-compressed archive contains a file name with shell metacharacters such as semicolons, pipes, or backticks, these characters can be interpreted by the shell during decompression, leading to arbitrary command execution. This represents a classic command injection vulnerability that aligns with CWE-78, which specifically addresses improper neutralization of special elements used in OS commands. The vulnerability operates at the operating system level where shell command execution occurs, making it particularly dangerous as it can potentially escalate privileges and provide attackers with full system control.
The operational impact of CVE-2016-1253 extends beyond simple remote code execution, as it can be leveraged in various attack scenarios including privilege escalation, data exfiltration, and system compromise. Attackers can craft malicious LZMA archives containing specially formatted file names that, when processed by the affected most package, execute arbitrary commands with the privileges of the user running the decompression utility. This vulnerability is particularly concerning in environments where automated decompression occurs or where users process untrusted archives from external sources. The attack vector is straightforward and requires minimal technical expertise, making it a popular target for automated exploitation tools. Systems that regularly handle compressed files, such as build servers, file sharing platforms, or automated deployment environments, are especially vulnerable to this type of attack.
Mitigation strategies for CVE-2016-1253 focus on updating the affected most package to versions that properly sanitize file names during decompression operations. Users should immediately upgrade to Debian package versions 5.0.0a-2.2 for wheezy, 5.0.0a-2.3+deb8u1 for jessie, and 5.0.0a-3 for unstable releases. Additionally, system administrators should implement file name validation policies that prevent the processing of compressed archives containing suspicious characters or patterns. Network segmentation and access controls can help limit the potential impact of successful exploitation attempts. Organizations should also consider implementing automated patch management systems to ensure timely deployment of security updates. The vulnerability demonstrates the importance of proper input validation and command construction practices, aligning with ATT&CK technique T1059.001 for command and script injection. Regular security audits should verify that decompression utilities properly handle special characters and that file name validation is consistently applied across all archive processing components to prevent similar vulnerabilities from emerging in other software packages.