CVE-2017-0359 in diffoscope
Summary
by MITRE
diffoscope before 77 writes to arbitrary locations on disk based on the contents of an untrusted archive.
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Analysis
by VulDB Data Team • 01/24/2020
The vulnerability identified as CVE-2017-0359 affects diffoscope version 77 and earlier, representing a critical directory traversal flaw that enables attackers to write files to arbitrary locations on the target system. This vulnerability arises from insufficient input validation within the archive processing functionality, where the software fails to properly sanitize file paths extracted from untrusted archive contents. The flaw allows malicious actors to manipulate archive entries containing specially crafted path sequences that can bypass normal file system access controls and write data to locations outside the intended extraction directory.
The technical implementation of this vulnerability stems from improper handling of file path normalization and validation during archive extraction operations. When diffoscope processes an archive, it reads file names and path information from the archive metadata without adequate sanitization of path traversal sequences such as ../ or ..\ that could potentially escape the designated extraction target. This weakness creates a path traversal condition that directly maps to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as directory traversal attacks. The vulnerability specifically manifests when the application attempts to extract files from untrusted archives, making it particularly dangerous in environments where users can upload or process third-party archives.
The operational impact of CVE-2017-0359 extends beyond simple file system manipulation to potentially enable full system compromise. Attackers can leverage this vulnerability to write malicious files to critical system locations such as /etc/ or /usr/bin/, potentially installing backdoors, modifying system binaries, or creating persistent access mechanisms. The vulnerability can be exploited through various archive formats including tar, zip, and other compressed formats that diffoscope supports for comparison operations. This makes it particularly dangerous in automated environments where diffoscope might be invoked on user-uploaded content, or in continuous integration pipelines where archive comparison is performed without proper input validation.
Security professionals should note that this vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1078 for Valid Accounts, as exploitation may enable attackers to establish persistent access through file system modifications. The vulnerability also represents a significant risk in web applications that process user-uploaded archives, as it can be exploited through server-side processing without requiring user interaction. Organizations should implement immediate mitigations including updating to diffoscope version 78 or later, which contains the necessary path validation fixes, and implementing strict input validation for all archive processing operations. Additional defensive measures include running diffoscope in restricted environments with limited write permissions, implementing network segmentation for archive processing services, and conducting regular security assessments to identify similar path traversal vulnerabilities in other software components.