CVE-2020-36280 in Leptonica
Summary
by MITRE • 03/12/2021
Leptonica before 1.80.0 allows a heap-based buffer over-read in pixReadFromTiffStream, related to tiffio.c.
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Analysis
by VulDB Data Team • 03/31/2021
The vulnerability identified as CVE-2020-36280 represents a critical heap-based buffer over-read flaw in Leptonica library versions prior to 1.80.0. This issue specifically affects the pixReadFromTiffStream function within the tiffio.c component, making it susceptible to memory corruption attacks that could potentially lead to system compromise. The vulnerability resides in the handling of TIFF image data streams where improper bounds checking allows an attacker to read memory beyond allocated buffer boundaries, creating opportunities for information disclosure and arbitrary code execution.
The technical implementation of this vulnerability stems from inadequate input validation within the TIFF stream parsing mechanism. When processing malformed or specially crafted TIFF files, the pixReadFromTiffStream function fails to properly verify buffer limits during data extraction operations, resulting in a heap-based buffer over-read condition. This flaw is classified under CWE-125 as an "Out-of-bounds Read" which represents a fundamental memory safety issue where the application accesses memory locations beyond the intended buffer boundaries. The vulnerability manifests when the library attempts to parse TIFF image data structures, particularly in scenarios involving compressed image formats or malformed metadata sections.
The operational impact of CVE-2020-36280 extends beyond simple memory corruption, as it provides attackers with potential pathways for privilege escalation and system compromise. Attackers could leverage this vulnerability through various attack vectors including web applications, email clients, or document processing systems that utilize Leptonica for image handling. The over-read condition could expose sensitive memory contents including stack canaries, heap metadata, or other application secrets that might aid in bypassing security mitigations such as stack canaries, address space layout randomization, or data execution prevention mechanisms. This vulnerability particularly affects systems where Leptonica is integrated into document processing pipelines, image conversion services, or security scanning applications that handle untrusted image input from external sources.
Mitigation strategies for this vulnerability require immediate patching of affected Leptonica installations to version 1.80.0 or later, which includes proper bounds checking and memory validation routines. Organizations should implement comprehensive input validation measures for all image processing workflows, including file format detection, size limitation, and sandboxed execution environments for image handling components. The implementation of memory safety techniques such as stack canaries, heap metadata protection, and address space layout randomization should be enforced across affected systems. Additionally, network segmentation and access controls should be implemented to limit exposure of services that process untrusted image data, aligning with ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1203 for Exploitation for Client Execution. Security monitoring should include detection of anomalous memory access patterns and buffer over-read conditions through log analysis and intrusion detection systems to identify potential exploitation attempts.