CVE-2017-1000126 in Exiv2
Summary
by MITRE
exiv2 0.26 contains a Stack out of bounds read in webp parser
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Analysis
by VulDB Data Team • 12/07/2019
The vulnerability CVE-2017-1000126 represents a critical stack out of bounds read flaw discovered in the exiv2 library version 0.26, specifically within its webp parser component. This vulnerability falls under the Common Weakness Enumeration category CWE-129, which addresses improper validation of array index values, and more specifically maps to CWE-125, which deals with out-of-bounds read conditions. The exiv2 library serves as a crucial metadata handling tool for various image formats including webp, jpeg, tiff, and others, making this vulnerability particularly dangerous as it affects a widely used library in both desktop and server environments.
The technical flaw manifests when the webp parser processes malformed webp image files, causing the application to read memory locations beyond the allocated stack buffer boundaries. This out of bounds read occurs during the parsing of webp metadata structures where the parser fails to properly validate the size parameters of various data segments before attempting to access memory locations. The vulnerability is classified as a memory safety issue that can lead to information disclosure, application crashes, or potentially more severe consequences if chained with other exploits. The parser does not perform adequate bounds checking on user-supplied data, allowing attackers to craft malicious webp files that trigger the out of bounds memory access when the library attempts to parse them.
The operational impact of this vulnerability extends across numerous applications and systems that depend on exiv2 for image metadata processing. Attackers can exploit this weakness by crafting specially formatted webp files that, when processed by vulnerable applications, cause the stack memory to be read beyond its intended boundaries. This could result in sensitive information leakage from adjacent memory locations, potentially exposing passwords, session tokens, or other confidential data. The vulnerability affects not only desktop applications but also server-side systems that process user-uploaded images, making it particularly dangerous in web applications and content management systems. The exploitability of this vulnerability is enhanced by the fact that exiv2 is commonly integrated into various multimedia applications, content management platforms, and image processing pipelines, creating multiple attack vectors.
Mitigation strategies for CVE-2017-1000126 should prioritize immediate patching of affected exiv2 versions, with the recommended solution being the upgrade to version 0.27 or later where the stack buffer overflow has been addressed. System administrators should implement strict input validation measures and consider deploying sandboxing mechanisms when processing untrusted image files. Additionally, organizations should conduct comprehensive vulnerability assessments to identify all systems utilizing vulnerable versions of exiv2 and ensure proper network segmentation to limit potential exploitation. The ATT&CK framework categorizes this vulnerability under the T1059.007 technique for application layer attacks, specifically targeting software libraries that process multimedia content. Regular security monitoring and log analysis should be implemented to detect potential exploitation attempts, while security teams should maintain awareness of related vulnerabilities in the same codebase that may present additional attack surfaces.