CVE-2022-23596 in Junrar
Summary
by MITRE • 02/01/2022
Junrar is an open source java RAR archive library. In affected versions A carefully crafted RAR archive can trigger an infinite loop while extracting said archive. The impact depends solely on how the application uses the library, and whether files can be provided by malignant users. The problem is patched in 7.4.1. There are no known workarounds and users are advised to upgrade as soon as possible.
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Analysis
by VulDB Data Team • 05/06/2025
The CVE-2022-23596 vulnerability affects Junrar, an open source java library designed for handling RAR archive files. This library serves as a critical component in numerous applications that require RAR file processing capabilities, making it a potential attack vector for malicious actors. The vulnerability manifests as an infinite loop condition during the extraction process of specifically crafted RAR archives, which can lead to system resource exhaustion and denial of service conditions. The flaw exists within the library's parsing and extraction algorithms that fail to properly validate or limit iteration cycles when processing malformed archive structures.
The technical implementation of this vulnerability stems from insufficient input validation within the RAR extraction logic. When a maliciously crafted RAR archive is processed by the Junrar library, the extraction routine enters an infinite loop due to improper boundary checking in the decompression algorithms. This condition occurs because the library does not adequately enforce iteration limits or validate the structural integrity of RAR archive headers and data streams. The vulnerability is classified under CWE-835 as an infinite loop without a valid exit condition, which represents a fundamental flaw in the control flow management of the extraction process. The infinite loop consumes CPU resources continuously until the system becomes unresponsive or the process is manually terminated.
The operational impact of CVE-2022-23596 extends beyond simple denial of service scenarios, as it can be leveraged in various attack vectors within the MITRE ATT&CK framework. Specifically, this vulnerability maps to the T1499.004 technique related to network denial of service, where attackers can exploit the infinite loop to exhaust system resources. Applications using the vulnerable Junrar library become susceptible to resource exhaustion attacks, particularly in environments where users can upload or provide RAR files, such as file sharing platforms, email attachment processing systems, or content management solutions. The vulnerability's exploitation potential increases significantly when applications lack proper resource monitoring or timeout mechanisms, as the infinite loop can persist until system resources are completely consumed.
Organizations and developers utilizing the Junrar library must implement immediate remediation measures to address this vulnerability. The official patch version 7.4.1 resolves the issue by introducing proper loop termination conditions and enhanced input validation within the RAR extraction routines. Security teams should prioritize upgrading all affected systems and applications to the patched version as soon as possible, as no effective workarounds exist for this particular vulnerability. Additionally, implementing proper input sanitization measures, establishing resource limits for archive processing, and deploying monitoring solutions to detect abnormal CPU usage patterns can provide additional defense-in-depth layers. The vulnerability highlights the importance of thorough testing for infinite loop conditions in archive processing libraries and demonstrates how seemingly benign parsing operations can become critical security concerns when proper validation mechanisms are absent.