CVE-2015-1395 in Patch
Summary
by MITRE
Directory traversal vulnerability in GNU patch versions which support Git-style patching before 2.7.3 allows remote attackers to write to arbitrary files with the permissions of the target user via a .. (dot dot) in a diff file name.
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Analysis
by VulDB Data Team • 12/16/2022
The vulnerability identified as CVE-2015-1395 represents a critical directory traversal flaw within GNU patch utility versions prior to 2.7.3, specifically when operating in Git-style patching mode. This vulnerability exposes systems to remote code execution risks through maliciously crafted diff files that contain directory traversal sequences. The flaw stems from inadequate input validation of file paths within patch operations, allowing attackers to manipulate the target location of file modifications through the use of .. (dot dot) sequences in filename specifications. The vulnerability operates at the core of file system access controls and path resolution mechanisms, creating a pathway for unauthorized file system modifications that can lead to privilege escalation or arbitrary code execution depending on the target user's permissions. This issue particularly affects environments where patch operations are performed on untrusted input, such as automated build systems, version control integrations, or any scenario involving patch processing from external sources.
The technical implementation of this vulnerability exploits the fundamental weakness in path normalization and validation within the GNU patch utility. When processing Git-style patches, the utility fails to properly sanitize or validate the file paths contained within the diff headers, allowing .. sequences to traverse parent directories. This flaw specifically manifests when the patch utility attempts to create or modify files in the target directory structure, where the .. components in filenames are not properly restricted or neutralized. The vulnerability is classified under CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The attack vector requires remote exploitation through the delivery of a malicious patch file that contains carefully crafted .. sequences in filenames, enabling attackers to bypass normal file system access controls and write to arbitrary locations within the target file system.
The operational impact of CVE-2015-1395 extends beyond simple file system manipulation to encompass potential privilege escalation and system compromise scenarios. When the patch utility executes with elevated privileges, such as during system updates or automated build processes, attackers can leverage this vulnerability to place malicious files in critical system locations, potentially leading to persistent backdoors or system compromise. The vulnerability affects any environment where GNU patch is used for processing external or untrusted patch files, including software development environments, continuous integration systems, automated deployment pipelines, and version control integration points. The risk is amplified in scenarios where patch operations are performed without proper user context isolation or privilege separation, allowing attackers to write to sensitive system directories or overwrite critical system files. This vulnerability directly aligns with ATT&CK technique T1059.001 for executing malicious code through command-line interfaces and T1566 for initial access through phishing or malicious file delivery mechanisms.
Mitigation strategies for CVE-2015-1395 primarily focus on upgrading to GNU patch version 2.7.3 or later, which includes proper input validation and path sanitization measures. Organizations should implement strict patch validation procedures for any external patch files and avoid processing untrusted patches in privileged contexts. System administrators should enforce privilege separation when executing patch operations and implement proper file system access controls to limit the impact of potential directory traversal attacks. Additionally, organizations should consider implementing automated patch validation tools that can detect and reject malicious path sequences before patch execution occurs. The vulnerability highlights the importance of input validation in file system operations and demonstrates how seemingly benign file processing utilities can become attack vectors when proper security controls are not implemented. Regular security assessments of file processing utilities and automated patching systems should include checks for similar path traversal vulnerabilities in other tools and utilities within the system environment.