CVE-2017-9953 in Exiv2
Summary
by MITRE
There is an invalid free in Image::printIFDStructure that leads to a Segmentation fault in Exiv2 0.26. A crafted input will lead to a remote denial of service attack.
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Analysis
by VulDB Data Team • 12/09/2022
The vulnerability identified as CVE-2017-9953 resides within the Exiv2 library version 0.26, specifically within the Image::printIFDStructure function. This issue represents a classic memory management flaw that occurs when processing malformed image files, particularly those containing crafted input data. The vulnerability manifests as an invalid free operation, which occurs when the software attempts to free memory that was either already freed or was never allocated through the standard memory allocation mechanisms. This improper memory handling directly leads to a segmentation fault during the processing of maliciously constructed image files, effectively causing the application to crash and resulting in a denial of service condition.
The technical root cause of this vulnerability can be categorized under CWE-415, which describes improper free operations in software systems. When the Image::printIFDStructure function processes image metadata structures, it encounters corrupted or malformed IFD (Image File Directory) entries that contain invalid pointers or corrupted memory references. The function attempts to free memory locations that do not conform to the expected memory allocation patterns, triggering the segmentation fault. This type of vulnerability is particularly dangerous because it can be exploited remotely through crafted image files that are processed by applications using the Exiv2 library, making it a significant concern for web applications and services that handle user-uploaded image content.
The operational impact of CVE-2017-9953 extends beyond simple service disruption, as it enables remote attackers to perform denial of service attacks against systems processing image files. This vulnerability affects any application that utilizes Exiv2 version 0.26 or earlier for image metadata processing, including content management systems, photo sharing platforms, web applications, and digital asset management solutions. The attack vector is particularly concerning because it requires minimal privileges from the attacker, as the vulnerability can be triggered simply by uploading or processing a malicious image file. The segmentation fault occurs during normal image processing operations, making it difficult to distinguish between legitimate and malicious input until the crash occurs, which can lead to prolonged service unavailability.
From an attack perspective, this vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through resource exhaustion or system crashes. The vulnerability can be exploited in scenarios where applications process user-uploaded content without proper input validation, allowing attackers to craft specially formatted image files that trigger the invalid free operation. Mitigation strategies should focus on immediate patching of Exiv2 to version 0.27 or later, where this vulnerability has been addressed through proper memory management practices. Additionally, implementing input validation and sanitization mechanisms for image files, employing sandboxing techniques for image processing, and deploying intrusion detection systems that monitor for abnormal memory access patterns can help reduce the risk of exploitation. Organizations should also consider implementing rate limiting and content filtering for image uploads to prevent abuse of this vulnerability in automated attack scenarios.