CVE-2018-20097 in Exiv2
Summary
by MITRE
There is a SEGV in Exiv2::Internal::TiffParserWorker::findPrimaryGroups of tiffimage_int.cpp in Exiv2 0.27-RC3. A crafted input will lead to a remote denial of service attack.
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Analysis
by VulDB Data Team • 06/18/2023
The vulnerability identified as CVE-2018-20097 represents a critical segmentation fault within the Exiv2 library version 0.27-RC3, specifically within the TIFF image parsing functionality. This issue manifests in the Exiv2::Internal::TiffParserWorker::findPrimaryGroups method located in the tiffimage_int.cpp source file. The flaw arises when the library processes malformed or crafted TIFF image data, causing the application to crash with a segmentation violation error. This type of vulnerability falls under the category of improper input validation and memory handling issues that can severely impact software stability and security posture.
The technical implementation of this vulnerability stems from inadequate bounds checking and null pointer dereference handling within the TIFF parser's internal worker class. When Exiv2 encounters malformed TIFF metadata structures, particularly those containing irregular group references or corrupted directory entries, the findPrimaryGroups method fails to properly validate input parameters before attempting to access memory locations. This results in the application attempting to read from or write to invalid memory addresses, leading to the segmentation fault that terminates the process. The vulnerability is classified as a buffer over-read or improper memory access pattern that can be exploited through carefully crafted TIFF files.
From an operational perspective, this vulnerability presents a significant remote denial of service risk for applications that rely on Exiv2 for image metadata processing. Attackers can craft malicious TIFF files that, when processed by vulnerable applications, will trigger the segmentation fault and cause service interruption. This affects a wide range of software including photo management applications, web servers processing image uploads, content management systems, and digital asset management platforms. The impact extends beyond simple service disruption as it can be leveraged in larger attack campaigns targeting availability of critical image processing services. The vulnerability demonstrates the importance of robust input validation and defensive programming practices in multimedia processing libraries.
Organizations utilizing Exiv2 should implement immediate mitigations including updating to the patched version of the library, implementing input sanitization measures, and deploying proper error handling around image processing functions. The vulnerability aligns with CWE-125: Out-of-Bounds Read and CWE-476: NULL Pointer Dereference, both of which are commonly exploited in remote code execution and denial of service scenarios. Security practitioners should also consider implementing network-based intrusion detection systems that can identify and block suspicious TIFF file patterns. Additionally, the ATT&CK framework categorizes this vulnerability under T1499.004: Endpoint Denial of Service, highlighting the need for comprehensive endpoint protection strategies. Regular security assessments and code reviews focusing on memory safety practices should be implemented to prevent similar issues in other image processing components and libraries.