CVE-2018-10886 in ant
Summary
by MITRE
ant before version 1.9.12 unzip and untar targets allows the extraction of files outside the target directory. A crafted zip or tar file submitted to an Ant build could create or overwrite arbitrary files with the privileges of the user running Ant.
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Analysis
by VulDB Data Team • 03/05/2020
The vulnerability identified as CVE-2018-10886 affects Apache Ant versions prior to 1.9.12 and specifically impacts the unzip and untar target functionalities within the build system. This flaw represents a critical directory traversal vulnerability that enables maliciously crafted archive files to bypass intended extraction boundaries and potentially overwrite system files or create arbitrary files in locations outside the designated target directory. The vulnerability stems from insufficient input validation and path sanitization within the archive extraction routines, allowing attackers to manipulate file paths during decompression operations. When Ant processes these malicious archives, it fails to properly validate or sanitize the file paths contained within the archive metadata, leading to path traversal conditions that can result in arbitrary file creation or modification.
The technical exploitation of this vulnerability occurs through the manipulation of archive file entries that contain relative path traversal sequences such as ../ or ..\ in their file names. When Ant processes these entries, it does not adequately filter or normalize the file paths before extracting them to the target directory, allowing the extraction process to write files to locations outside the intended extraction scope. This behavior creates a significant security risk because Ant typically runs with the privileges of the user executing the build process, meaning that successful exploitation can result in arbitrary file system modifications with the same privileges as the Ant process itself. The vulnerability affects both zip and tar archive formats, expanding the potential attack surface and making it particularly dangerous in environments where Ant is used for automated build processes or continuous integration pipelines.
The operational impact of CVE-2018-10886 extends beyond simple privilege escalation to encompass potential system compromise through various attack vectors. An attacker who can influence the contents of an archive file processed by Ant could potentially overwrite critical system files, create backdoor executables, or modify configuration files to gain persistent access to the system. This vulnerability is particularly concerning in automated build environments where Ant processes archives from untrusted sources, such as dependency downloads or source code repositories. The vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, and can be mapped to ATT&CK technique T1059.007 for executing malicious code through build systems. In enterprise environments, this vulnerability can be leveraged to compromise build servers, CI/CD pipelines, or development workstations where Ant is used for automated processes, potentially leading to supply chain attacks or lateral movement within the network infrastructure.
Organizations should implement immediate mitigations including upgrading to Apache Ant version 1.9.12 or later, which contains the necessary patches to address the path traversal vulnerability. Additional defensive measures include implementing strict input validation for archive files in build processes, restricting Ant execution privileges to minimal required permissions, and establishing secure artifact repositories that ensure all downloaded dependencies are verified and trusted. Security teams should also monitor build systems for suspicious archive file processing and implement automated scanning tools to detect potentially malicious archive content. The vulnerability demonstrates the importance of proper input validation in archive processing utilities and highlights the need for security considerations in build automation systems. Organizations should conduct comprehensive vulnerability assessments of their build environments to identify all instances of Ant installations that may be vulnerable to this issue, particularly in continuous integration and deployment pipelines where automated processing of external artifacts occurs.