CVE-2018-19567 in dcraw
Summary
by MITRE
A floating point exception in parse_tiff_ifd in dcraw through 9.28 could be used by attackers able to supply malicious files to crash an application that bundles the dcraw code.
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Analysis
by VulDB Data Team • 04/15/2020
The vulnerability identified as CVE-2018-19567 represents a critical floating point exception within the dcraw library version 9.28 and earlier, specifically occurring in the parse_tiff_ifd function. This flaw manifests when applications that incorporate the dcraw code process maliciously crafted TIFF image files, creating potential for denial of service attacks or more severe exploitation scenarios. The vulnerability stems from inadequate input validation and error handling within the image parsing routine that processes TIFF file metadata structures.
The technical implementation of this vulnerability involves a floating point exception that occurs during the parsing of TIFF Image File Directory (IFD) structures. When dcraw encounters malformed or maliciously constructed TIFF files, the parse_tiff_ifd function fails to properly handle certain floating point operations, resulting in an unhandled exception that causes the application to terminate abruptly. This behavior aligns with CWE-191, which describes integer underflow conditions, though the specific manifestation here involves floating point arithmetic errors. The flaw demonstrates poor defensive programming practices where the code does not adequately validate input parameters before performing mathematical operations.
From an operational perspective, this vulnerability poses significant risks to applications that rely on dcraw for image processing, including digital asset management systems, photo editing software, and web applications that accept user-uploaded image files. Attackers can exploit this by crafting malicious TIFF files that trigger the floating point exception, leading to application crashes and potential service disruption. The impact extends beyond simple denial of service as this vulnerability could potentially be leveraged in more sophisticated attacks where the crashing behavior might be used to facilitate further exploitation or as part of a broader attack chain. The vulnerability affects any software that directly or indirectly uses the affected version of dcraw, making it particularly concerning for widely used open source libraries.
Mitigation strategies for CVE-2018-19567 should prioritize immediate patching of affected applications to incorporate dcraw version 9.29 or later, which contains the necessary fixes for the floating point exception handling. System administrators should implement input validation measures that screen for malformed image files before processing, particularly in web applications that accept user uploads. Additionally, deploying application sandboxing techniques and implementing proper error handling that prevents unhandled exceptions from crashing applications can provide additional layers of protection. Organizations should also consider implementing monitoring systems to detect unusual application crash patterns that might indicate exploitation attempts. The ATT&CK framework categorizes this vulnerability under T1499.004 for Network Denial of Service and T1059.007 for Command and Scripting Interpreter, highlighting potential exploitation vectors that could be used to escalate the initial denial of service into more sophisticated attacks.