CVE-2018-20846 in OpenJPEG
Summary
by MITRE
Out-of-bounds accesses in the functions pi_next_lrcp, pi_next_rlcp, pi_next_rpcl, pi_next_pcrl, pi_next_rpcl, and pi_next_cprl 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-2018-20846 represents a critical out-of-bounds memory access issue within the OpenJPEG library version 2.3.0 and earlier. This flaw exists in multiple functions within the pi.c file including pi_next_lrcp, pi_next_rlcp, pi_next_rpcl, pi_next_pcrl, and pi_next_cprl, which are part of the library's processing routines for handling JPEG 2000 image format operations. The vulnerability stems from insufficient input validation and boundary checking within these functions, allowing maliciously crafted JPEG 2000 files to trigger memory access violations when the library attempts to process them.
The technical nature of this vulnerability aligns with CWE-129, which addresses insufficient input validation, and CWE-787, which covers out-of-bounds write operations. These functions appear to process different types of packet information within JPEG 2000 streams, with each function handling specific packet characteristics such as left-right, right-left, and various other combinations. When an attacker provides malformed input data that exceeds expected boundaries, the functions fail to properly validate array indices or memory offsets, leading to memory corruption that results in application crashes. The vulnerability is particularly concerning as it can be exploited remotely through the processing of maliciously crafted JPEG 2000 files, making it a significant denial of service risk.
The operational impact of this vulnerability extends beyond simple application crashes, as it can be leveraged by attackers to disrupt services that rely on OpenJPEG for image processing. Systems that accept user-uploaded JPEG 2000 files, such as web applications, content management systems, and image processing servers, become vulnerable to this attack vector. The vulnerability can be exploited across various platforms where OpenJPEG is integrated, including web browsers through plugins, mobile applications, and server-side processing systems. This makes it a particularly attractive target for attackers seeking to disrupt services or potentially escalate to more severe exploits through cascading failures.
From an ATT&CK framework perspective, this vulnerability maps to T1499.004, which covers network denial of service attacks, and T1059, which involves command and scripting interpreters. The vulnerability can be classified as a remote code execution vector through service disruption, as it allows attackers to cause applications to crash and become unavailable to legitimate users. The exploitation requires minimal privileges and can be automated, making it suitable for widespread deployment in botnets or automated attack frameworks. Organizations should implement immediate mitigations including updating to OpenJPEG versions 2.3.1 or later where this vulnerability has been patched, and deploying input validation measures to prevent processing of malformed JPEG 2000 files. Additionally, network segmentation and monitoring for unusual application crash patterns can help detect exploitation attempts, while maintaining up-to-date security patches across all systems utilizing OpenJPEG components.