CVE-2018-8017 in Tika
Summary
by MITRE
In Apache Tika 1.2 to 1.18, a carefully crafted file can trigger an infinite loop in the IptcAnpaParser.
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Analysis
by VulDB Data Team • 03/25/2020
The vulnerability CVE-2018-8017 represents a critical denial of service flaw affecting Apache Tika versions 1.2 through 1.18, where specifically crafted malicious files can induce infinite loops within the IptcAnpaParser component. This parser is responsible for extracting metadata from image files using the IPTC ANPA (Associated Press) standard, which is commonly used in media and journalism workflows. The flaw manifests when the parser encounters malformed or specially constructed IPTC data within image files, causing it to enter an infinite processing loop that consumes excessive system resources and renders the application unresponsive.
The technical implementation of this vulnerability resides in the parsing logic of the IptcAnpaParser class, which fails to properly validate the structure and boundaries of IPTC metadata fields. When processing certain malformed files, the parser's internal state management becomes corrupted, leading to recursive or iterative processing that never terminates. This behavior stems from inadequate input validation and missing loop termination conditions in the parser's control flow mechanisms. The vulnerability is classified as a CWE-835: Loop with Unreachable Exit Condition (Loop Condition is not updated) which directly maps to the infinite loop scenario described in the CVE. The flaw can be triggered through any file processing operation that involves IPTC metadata extraction, making it particularly dangerous in automated processing environments where batch operations are common.
The operational impact of CVE-2018-8017 extends beyond simple service disruption, as it can be exploited to exhaust system resources including CPU cycles, memory, and process limits. In high-volume processing environments such as content management systems, digital asset management platforms, or automated ingestion pipelines, this vulnerability can lead to complete system paralysis or denial of service attacks against legitimate users. Attackers can craft malicious files that appear legitimate to end users but contain the specific IPTC data structures designed to trigger the infinite loop. The vulnerability is particularly concerning in cloud environments where resource consumption can lead to cascading failures and increased operational costs due to resource exhaustion.
Mitigation strategies for CVE-2018-8017 require immediate action to upgrade to Apache Tika version 1.19 or later, where the infinite loop issue has been resolved through proper input validation and loop boundary enforcement. Organizations should implement strict file validation processes before processing any content through Tika parsers, particularly for files containing IPTC metadata. Network-based mitigations can include implementing file size limits, content type restrictions, and automated scanning for known malicious patterns in IPTC data structures. Additionally, system administrators should deploy monitoring solutions that can detect unusual CPU or memory consumption patterns that may indicate exploitation attempts. The ATT&CK framework categorizes this vulnerability under T1499.004: Endpoint Denial of Service, as it specifically targets the availability of endpoint systems through resource exhaustion. Organizations should also consider implementing sandboxing techniques for processing untrusted files and establishing incident response procedures specifically for handling denial of service vulnerabilities in document processing systems.