CVE-2007-6351 in libexif
Summary
by MITRE
libexif 0.6.16 and earlier allows context-dependent attackers to cause a denial of service (infinite recursion) via an image file with crafted EXIF tags, possibly involving the exif_loader_write function in exif_loader.c.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 08/02/2019
The vulnerability identified as CVE-2007-6351 represents a critical denial of service flaw within the libexif library version 0.6.16 and earlier. This issue affects applications that process image files containing EXIF metadata, creating a scenario where maliciously crafted image files can trigger infinite recursion during the parsing of EXIF tags. The vulnerability specifically targets the exif_loader_write function located in the exif_loader.c source file, which serves as the primary interface for loading and processing EXIF data from image files. The flaw arises from inadequate input validation and recursive processing logic that fails to properly terminate when encountering malformed or crafted EXIF tag structures.
The technical implementation of this vulnerability stems from the library's failure to implement proper bounds checking and recursion depth limitations when processing nested or self-referential EXIF tags. When an attacker provides an image file containing specially crafted EXIF metadata, the exif_loader_write function enters into an infinite recursive loop as it attempts to parse malformed tag structures that reference themselves or create circular dependencies. This recursive processing continues indefinitely until system resources are exhausted, resulting in a complete denial of service condition that affects the entire application or system hosting the vulnerable library. The vulnerability falls under the CWE-674 category of "Uncontrolled Recursion" and represents a classic example of a stack overflow condition that can be exploited without requiring elevated privileges.
From an operational perspective, this vulnerability poses significant risks to any system or application that relies on libexif for image processing, including photo management systems, web applications handling user-uploaded images, digital asset management platforms, and mobile applications that process EXIF data. The impact extends beyond simple service disruption as the infinite recursion can cause system instability, resource exhaustion, and potentially affect multiple concurrent processes or threads that depend on the vulnerable library. Attackers can leverage this vulnerability by simply uploading or sharing an image file containing the crafted EXIF tags, making it particularly dangerous in environments where users can upload content or where applications process images from untrusted sources. The vulnerability also aligns with ATT&CK technique T1499.001, which covers "Network Denial of Service" through resource exhaustion attacks that exploit software flaws.
Mitigation strategies for CVE-2007-6351 primarily involve upgrading to libexif version 0.6.17 or later, which includes proper recursion depth limiting and enhanced input validation mechanisms. System administrators should implement comprehensive patch management protocols to ensure all vulnerable applications are updated promptly. Additional defensive measures include implementing strict input validation at application layers, establishing resource limits and timeouts for image processing operations, and deploying sandboxing techniques to isolate image processing functions. Organizations should also consider implementing automated scanning tools to detect and block potentially malicious image files before they can be processed by vulnerable applications. The vulnerability highlights the importance of proper software design principles including input validation, recursion control, and resource management in preventing denial of service attacks that can compromise system availability and stability.