CVE-2018-6616 in OpenJPEG
Summary
by MITRE
In OpenJPEG 2.3.0, there is excessive iteration in the opj_t1_encode_cblks function of openjp2/t1.c. Remote attackers could leverage this vulnerability to cause a denial of service via a crafted bmp file.
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Analysis
by VulDB Data Team • 02/03/2023
The vulnerability identified as CVE-2018-6616 affects OpenJPEG version 2.3.0 and represents a critical denial of service flaw within the library's JPEG 2000 implementation. This issue resides in the opj_t1_encode_cblks function located in the openjp2/t1.c source file, where excessive iteration occurs during the encoding process of bitmap files. The vulnerability specifically manifests when processing crafted bmp files that trigger abnormal loop behavior in the compression algorithm. The flaw stems from inadequate input validation and loop termination conditions that fail to properly handle malformed or maliciously constructed bitmap data structures.
The technical nature of this vulnerability aligns with CWE-835, which describes the weakness of infinite or very long loops that can lead to denial of service conditions. Attackers can exploit this weakness by crafting specially formatted bmp files that, when processed by the vulnerable OpenJPEG library, cause the opj_t1_encode_cblks function to enter into computationally expensive iteration cycles. The excessive iteration consumes system resources including cpu cycles and memory allocation, ultimately leading to system performance degradation or complete service unavailability. This type of vulnerability operates at the intersection of software robustness and security, where normal program flow becomes disrupted by malicious input patterns.
The operational impact of CVE-2018-6616 extends beyond simple resource exhaustion to potentially affect any application or system that relies on OpenJPEG for image processing tasks. Systems using this library for image conversion, web applications handling user-uploaded images, or any software that processes bitmap files through the affected library become vulnerable to this denial of service attack. The remote exploitation capability means that attackers can trigger the vulnerability without requiring local access, making it particularly dangerous in networked environments. This vulnerability directly maps to ATT&CK technique T1499.004, which covers network denial of service attacks, and represents a classic example of how seemingly benign input processing can become a vector for system disruption.
Mitigation strategies for CVE-2018-6616 should focus on immediate software updates to patched versions of OpenJPEG that address the excessive iteration issue in the opj_t1_encode_cblks function. Organizations should implement input validation measures to detect and reject malformed bitmap files before they reach the vulnerable library components. Additionally, system administrators should consider implementing resource limits and timeouts for image processing operations to prevent complete system exhaustion. The vulnerability demonstrates the importance of proper loop bounds checking and input sanitization in cryptographic and image processing libraries, as outlined in secure coding practices recommended by both NIST and ISO standards for software security engineering.