CVE-2011-0402 in dpkg
Summary
by MITRE
dpkg-source in dpkg before 1.14.31 and 1.15.x allows user-assisted remote attackers to modify arbitrary files via a symlink attack on unspecified files in the .pc directory.
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Analysis
by VulDB Data Team • 10/11/2021
The vulnerability identified as CVE-2011-0402 affects the dpkg-source utility within the dpkg package management system, specifically versions prior to 1.14.31 and all 1.15.x releases. This issue represents a significant security flaw that enables malicious actors to manipulate the package build process through symbolic link manipulation. The vulnerability occurs within the .pc directory, which serves as a staging area for patch management during package compilation. The flaw arises from inadequate file handling mechanisms that fail to properly validate or sanitize symbolic link references during the extraction and processing of package source files.
The technical implementation of this vulnerability stems from a lack of proper symlink validation within the dpkg-source utility's file processing routines. When processing package source archives, the utility creates temporary files and directories in the .pc folder structure without adequately checking for existing symbolic links that might point to arbitrary locations on the filesystem. This oversight allows an attacker who can influence the package build process to establish malicious symbolic links that redirect file operations to unintended destinations. The vulnerability operates under the principle of privilege escalation through file system manipulation, where a user-assisted remote attacker can leverage this weakness to modify files outside the intended package build context.
The operational impact of this vulnerability extends beyond simple file modification capabilities and represents a serious threat to system integrity and security. An attacker could potentially overwrite critical system files, inject malicious code into package builds, or manipulate configuration files that are processed during package installation. This flaw particularly affects environments where package building occurs with elevated privileges or where untrusted source packages are processed. The vulnerability enables attackers to compromise the package management system's integrity, potentially leading to persistent backdoors, privilege escalation, or complete system compromise depending on the target files being modified.
Mitigation strategies for CVE-2011-0402 primarily focus on upgrading to dpkg versions 1.14.31 or later, which contain the necessary patches to address the symlink handling issues. System administrators should implement strict package source validation procedures and avoid processing untrusted source packages in environments where package building occurs with elevated privileges. The remediation process should include comprehensive testing of package build environments to ensure that no symbolic links exist in the .pc directory or other temporary build locations that could be exploited. Additionally, organizations should consider implementing automated scanning tools to detect potential symbolic link vulnerabilities in their package management workflows, aligning with the security principles outlined in the CWE-59 standard for improper link resolution. This vulnerability demonstrates the critical importance of proper file system access controls and the need for robust input validation in package management systems, as detailed in relevant ATT&CK techniques for privilege escalation and persistence mechanisms.