CVE-2018-20845 in OpenJPEG
Summary
by MITRE
Division-by-zero vulnerabilities in the functions pi_next_pcrl, pi_next_cprl, and pi_next_rpcl in openmj2/pi.c in OpenJPEG through 2.3.0 allow remote attackers to cause a denial of service (application crash).
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Analysis
by VulDB Data Team • 10/08/2023
The vulnerability identified as CVE-2018-20845 represents a critical division-by-zero flaw within the OpenJPEG library version 2.3.0 and earlier. This issue affects the core image processing functionality of the library, specifically within the pi_next_pcrl, pi_next_cprl, and pi_next_rpcl functions located in the openmj2/pi.c file. These functions are responsible for processing image data during the progression of JPEG 2000 decoding operations, making them integral to the library's ability to handle compressed image formats.
The technical nature of this vulnerability stems from improper input validation within the affected functions, where division operations occur without adequate checks for zero denominators. When maliciously crafted JPEG 2000 files are processed by applications using the vulnerable OpenJPEG library, the functions attempt to divide by zero during their normal execution flow, resulting in immediate application termination. This behavior manifests as a denial of service condition that can be exploited remotely by attackers who can submit specially crafted image files to systems that rely on OpenJPEG for image processing.
From an operational perspective, this vulnerability poses significant risks to systems that utilize OpenJPEG for image handling, particularly those exposed to untrusted input sources such as web applications, image processing servers, or any system accepting user-uploaded images. The impact extends beyond simple service disruption as it can be leveraged in broader attack scenarios targeting availability of critical image processing services. The vulnerability affects the library's robustness and can be exploited by attackers to cause persistent service degradation across multiple applications that depend on OpenJPEG for JPEG 2000 format support.
The flaw aligns with CWE-369, which specifically addresses the division by zero weakness, and can be mapped to ATT&CK technique T1499.004 for network denial of service attacks. Organizations using vulnerable versions of OpenJPEG should prioritize immediate remediation through library updates to version 2.3.1 or later, where the division-by-zero conditions have been addressed. Additionally, implementing input validation measures and sanitization of image files before processing can serve as temporary mitigations while awaiting official patches. System administrators should also consider network segmentation and access controls to limit exposure of services that process external image uploads, reducing the attack surface for potential exploitation of this vulnerability.