CVE-2020-23707 in ok-file-formats
Summary
by MITRE • 07/16/2021
A heap-based buffer overflow vulnerability in the function ok_jpg_decode_block_progressive() at ok_jpg.c:1054 of ok-file-formats through 2020-06-26 allows attackers to cause a Denial of Service (DOS) via a crafted jpeg file.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 07/19/2021
The heap-based buffer overflow vulnerability identified as CVE-2020-23707 resides within the ok-file-formats library, specifically within the ok_jpg_decode_block_progressive() function located at line 1054 of the ok_jpg.c source file. This vulnerability affects versions of the library released through June 26, 2020, and represents a critical security flaw that can be exploited by malicious actors to disrupt system operations. The vulnerability stems from improper input validation and memory management within the JPEG decoding process, where the function fails to properly bounds-check data during progressive JPEG decompression operations. The issue manifests when processing specially crafted JPEG files that contain malformed progressive JPEG markers or data sequences that exceed expected buffer boundaries.
The technical exploitation of this vulnerability occurs during the progressive JPEG decoding phase where the ok_jpg_decode_block_progressive() function attempts to write data beyond the allocated heap memory buffer. This heap-based buffer overflow creates a condition where attacker-controlled data can overwrite adjacent memory locations, potentially leading to arbitrary code execution or system instability. The vulnerability is classified as a heap overflow under CWE-122, which specifically addresses insufficient checking of the size of input data when allocating heap memory. The flaw is particularly dangerous because it operates during the normal processing of JPEG files, making it difficult to detect and prevent through standard input sanitization measures. When an application using the affected library processes a malicious JPEG file, the buffer overflow can trigger memory corruption that results in application crashes or complete system denial of service.
The operational impact of CVE-2020-23707 extends beyond simple denial of service conditions, as it can be leveraged to cause more severe system disruptions across various software applications that rely on the ok-file-formats library. Systems utilizing this library for image processing, document management, or media handling applications become vulnerable to exploitation by attackers who can craft malicious JPEG files to trigger the overflow condition. The vulnerability affects any software stack that incorporates the affected library, including web applications, mobile applications, and desktop software that process JPEG images. From an adversary perspective, this vulnerability aligns with ATT&CK technique T1203, which involves the exploitation of software vulnerabilities to gain unauthorized access or cause system disruption. The attack surface is broad since JPEG is a widely used image format across numerous platforms and applications, making the potential impact of this vulnerability significant for organizations relying on affected software.
Mitigation strategies for CVE-2020-23707 should prioritize immediate remediation through version updates that address the heap overflow condition in the ok-file-formats library. Organizations must ensure all systems using this library are updated to versions that contain proper bounds checking and memory management controls within the JPEG decoding functions. Additionally, implementing input validation measures that sanitize JPEG file contents before processing can provide defense-in-depth protection against exploitation attempts. Network-based detection mechanisms should monitor for suspicious JPEG file patterns that may indicate attempts to exploit this vulnerability. The fix should include proper buffer size validation and memory allocation checks within the ok_jpg_decode_block_progressive() function to prevent overflow conditions during progressive JPEG processing. Security teams should also consider implementing application sandboxing and privilege separation techniques to limit the potential impact of successful exploitation attempts. Regular vulnerability assessments and dependency updates should be maintained to prevent similar issues from arising in the future, with particular attention to memory safety considerations in image processing libraries that handle untrusted input data.