CVE-2022-30126: Apache Tika DOS Vulnerability

CVE-2022-30126 Overview

CVE-2022-30126 is a Regular Expression Denial of Service (ReDoS) vulnerability affecting Apache Tika, a content detection and analysis toolkit. The vulnerability exists in the StandardsText class used by the StandardsExtractingContentHandler, where a poorly crafted regular expression can cause catastrophic backtracking when processing specially crafted files. This can lead to excessive CPU consumption and denial of service conditions.

Critical Impact

Attackers can craft malicious files that exploit the regex backtracking vulnerability, causing the application to become unresponsive and consuming excessive CPU resources, effectively denying service to legitimate users.

Affected Products

• Apache Tika versions prior to 1.28.2
• Apache Tika versions 2.x prior to 2.4.0
• Oracle Primavera Unifier versions 18.8, 19.12, 20.12, 21.12

Discovery Timeline

• May 16, 2022 - CVE-2022-30126 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2022-30126

Vulnerability Analysis

This vulnerability is classified as an Algorithmic Complexity Attack, specifically a Regular Expression Denial of Service (ReDoS). The StandardsText class within Apache Tika contains a regular expression pattern that exhibits exponential time complexity when matched against certain input strings. When the StandardsExtractingContentHandler processes a specially crafted file, the regex engine enters a catastrophic backtracking state, causing the CPU to spike and the application to become unresponsive.

The vulnerability requires local access and user interaction, as the attacker must convince a user or automated process to parse a malicious file using the vulnerable StandardsExtractingContentHandler. While this limits the attack surface, organizations using Apache Tika for document processing pipelines or content management systems may be particularly vulnerable.

Root Cause

The root cause of this vulnerability lies in the inefficient regular expression pattern used within the StandardsText class. Regular expressions with nested quantifiers or overlapping alternatives can cause the regex engine to explore an exponentially growing number of matching possibilities. When combined with carefully crafted input that maximizes backtracking, this results in denial of service through CPU exhaustion.

The vulnerability specifically affects the StandardsExtractingContentHandler, which is a non-standard handler used to extract standards references from documents. While this limits the impact to users who have explicitly enabled this handler, it still poses a significant risk in environments where document processing is automated.

Attack Vector

The attack requires local file access and user interaction to exploit. An attacker would craft a malicious file containing input strings specifically designed to trigger the regex backtracking vulnerability. The attack flow typically involves:

1. The attacker creates a specially crafted document containing patterns that exploit the vulnerable regex
2. The malicious file is submitted to an application using Apache Tika with the StandardsExtractingContentHandler enabled
3. When Tika processes the file, the regex engine enters catastrophic backtracking
4. CPU resources are exhausted, causing denial of service

The vulnerability manifests in the regex pattern matching logic within the StandardsText class. When the StandardsExtractingContentHandler processes document content, it applies regular expressions to identify standards references. A malicious input string can cause the regex engine to explore an exponential number of match possibilities, effectively halting the application. For technical details, refer to the Apache Mailing List Thread.

Detection Methods for CVE-2022-30126

Indicators of Compromise

• Abnormally high CPU utilization on systems running Apache Tika document processing
• Application threads stuck in regex matching operations for extended periods
• Document processing queues backing up without apparent network or I/O bottlenecks
• Java process memory and CPU spikes correlated with specific document uploads

Detection Strategies

• Monitor for sudden CPU spikes in Java processes running Apache Tika, particularly during document ingestion
• Implement application-level timeout monitoring for document parsing operations
• Configure alerting for processing threads that exceed normal execution time thresholds
• Review application logs for stuck or unresponsive StandardsExtractingContentHandler operations

Monitoring Recommendations

• Establish baseline metrics for document processing times and CPU utilization
• Deploy APM (Application Performance Monitoring) solutions to track Tika processing latency
• Configure automated alerts when document processing exceeds defined time thresholds
• Monitor Java heap and thread dumps for evidence of regex-related performance issues

How to Mitigate CVE-2022-30126

Immediate Actions Required

• Upgrade Apache Tika to version 1.28.2 or later for the 1.x branch
• Upgrade Apache Tika to version 2.4.0 or later for the 2.x branch
• Review whether the StandardsExtractingContentHandler is enabled in your deployment and disable if not required
• Apply relevant patches from Oracle for Primavera Unifier if affected

Patch Information

Apache has addressed this vulnerability in Apache Tika versions 1.28.2 and 2.4.0. The fix involves optimizing the regular expression pattern in the StandardsText class to prevent catastrophic backtracking. Organizations should upgrade to these patched versions immediately.

For Oracle Primavera Unifier users, refer to the Oracle Critical Patch Update July 2022 for applicable patches. Additional vendor security guidance is available from NetApp Security Advisory NTAP-20220624-0004.

Workarounds

• Disable the StandardsExtractingContentHandler if standards extraction functionality is not required
• Implement input validation and file size limits for documents processed by Apache Tika
• Configure processing timeouts to terminate long-running parsing operations
• Deploy document processing in isolated environments with resource limits to contain potential DoS impact

# Example: Setting processing timeout in Tika configuration
# Set maximum parsing time to prevent resource exhaustion
export TIKA_PARSE_TIMEOUT_MS=60000

# Verify Apache Tika version to ensure patched version is installed
java -jar tika-app-2.4.0.jar --version