CVE-2018-1339 in Tika
Summary
by MITRE
A carefully crafted (or fuzzed) file can trigger an infinite loop in Apache Tika's ChmParser in versions of Apache Tika before 1.18.
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Analysis
by VulDB Data Team • 03/07/2023
The vulnerability identified as CVE-2018-1339 represents a critical denial of service weakness within Apache Tika's handling of CHM (Compiled HTML Help) files. This flaw exists in Apache Tika versions prior to 1.18 and stems from inadequate input validation within the ChmParser component. The issue manifests when processing specifically crafted or fuzzed CHM files that contain malformed structures designed to exploit control flow mechanisms within the parsing logic.
The technical root cause of this vulnerability lies in the ChmParser implementation which fails to properly validate the structure and loop conditions within CHM file formats. When encountering maliciously constructed CHM files, the parser enters an infinite loop due to missing boundary checks and proper termination conditions. This behavior aligns with CWE-835, which specifically addresses the issue of loops that do not terminate properly. The vulnerability exploits the fundamental parsing logic that should handle various CHM file structures but instead becomes trapped in recursive or iterative constructs that lack proper exit conditions.
From an operational perspective, this vulnerability presents significant risks to organizations relying on Apache Tika for document processing and content extraction. An attacker could exploit this weakness by uploading or providing a malicious CHM file to any system running vulnerable versions of Apache Tika, potentially causing system resources to become exhausted through continuous processing cycles. The impact extends beyond simple service disruption as it can affect automated document processing pipelines, content management systems, and any application that integrates Apache Tika for file analysis. This vulnerability is particularly concerning in environments where automated processing of user-uploaded content occurs, as it could enable attackers to consume system resources indefinitely.
The exploitation of this vulnerability follows patterns consistent with ATT&CK technique T1499.004, which involves resource exhaustion through malicious file processing. Organizations should implement immediate mitigations including upgrading to Apache Tika version 1.18 or later, which contains the necessary patches to prevent infinite loop conditions in the ChmParser. Additionally, organizations should consider implementing file validation mechanisms that detect and reject CHM files with suspicious structures before they reach the parsing stage. Network-based detection systems should also be configured to monitor for unusual processing patterns that might indicate exploitation attempts. The remediation process should include thorough testing of the updated Tika version to ensure that legitimate CHM file processing continues to function properly while eliminating the infinite loop vulnerability.
This vulnerability demonstrates the importance of proper input validation and boundary checking in file parsing libraries, particularly those handling complex file formats with intricate internal structures. The ChmParser's failure to properly handle malformed input represents a classic example of how insufficient defensive programming can lead to severe operational impacts. Organizations should also consider implementing additional security controls such as process timeouts, memory limits, and resource monitoring to provide defense-in-depth against similar vulnerabilities. The incident underscores the necessity of regular security assessments and timely patch management for all components within document processing pipelines, as even seemingly minor parsing flaws can have significant operational consequences when exploited in real-world scenarios.