CVE-2022-42969 in py Library
Summary
by MITRE • 10/16/2022
The py library through 1.11.0 for Python allows remote attackers to conduct a ReDoS (Regular expression Denial of Service) attack via a Subversion repository with crafted info data, because the InfoSvnCommand argument is mishandled.
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Analysis
by VulDB Data Team • 08/03/2024
The vulnerability identified as CVE-2022-42969 represents a critical Regular Expression Denial of Service (ReDoS) flaw within the py library version 1.11.0 and earlier. This issue specifically affects Python environments that utilize the py library for interacting with Subversion repositories. The vulnerability stems from improper handling of the InfoSvnCommand argument when processing repository information data, creating a pathway for remote attackers to exploit the system through carefully crafted malicious input sequences.
The technical root cause of this vulnerability lies in the library's inadequate validation and sanitization of input data when parsing Subversion repository information. When the py library processes information data from a Subversion repository, it employs regular expressions that are susceptible to catastrophic backtracking patterns. Attackers can construct malicious input strings that cause the regular expression engine to consume excessive computational resources, leading to denial of service conditions where legitimate operations become impossible to complete. This vulnerability operates at the intersection of software input validation and regular expression processing, making it particularly dangerous in networked environments where external data sources are common.
The operational impact of CVE-2022-42969 extends beyond simple service disruption to potentially compromise entire application availability. Systems utilizing the py library for Subversion repository interactions become vulnerable to resource exhaustion attacks that can consume CPU cycles and memory resources to the point of system instability. This vulnerability affects both automated processes and manual operations that depend on repository information retrieval, creating cascading effects throughout software development workflows and continuous integration pipelines. The remote nature of the attack means that threat actors can exploit this vulnerability without requiring physical access to the target system, making it particularly concerning for organizations with distributed development teams.
Mitigation strategies for CVE-2022-42969 should prioritize immediate patching of the py library to versions that address the regular expression handling issues. Organizations should implement input validation measures that sanitize all repository information data before processing, particularly focusing on identifying and rejecting suspicious patterns that could trigger catastrophic backtracking. Network segmentation and rate limiting mechanisms can help reduce the impact of potential attacks by limiting the number of requests that can be processed within a given timeframe. Additionally, implementing monitoring solutions that detect unusual CPU usage patterns or excessive processing times during repository operations can provide early warning of exploitation attempts. This vulnerability aligns with CWE-400, which addresses improper input validation, and maps to ATT&CK technique T1499.004 for resource exhaustion attacks. Organizations should also consider implementing defensive coding practices that avoid using untrusted regular expressions and instead employ more secure alternatives such as bounded regex engines or alternative parsing methodologies to prevent similar vulnerabilities from occurring in other components of their software infrastructure.