CVE-2012-2837 in libexif
Summary
by MITRE
The mnote_olympus_entry_get_value function in olympus/mnote-olympus-entry.c in the EXIF Tag Parsing Library (aka libexif) before 0.6.21 allows remote attackers to cause a denial of service (divide-by-zero error) via an image with crafted EXIF tags that are not properly handled during the formatting of EXIF maker note tags.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 12/06/2021
The vulnerability identified as CVE-2012-2837 resides within the EXIF Tag Parsing Library, commonly known as libexif, specifically in the mnote_olympus_entry_get_value function located in olympus/mnote-olympus-entry.c. This flaw represents a critical security issue that affects versions of libexif prior to 0.6.21, creating a potential pathway for remote attackers to execute denial of service attacks through carefully crafted EXIF metadata within image files.
The technical implementation of this vulnerability stems from improper handling of EXIF maker note tags during the formatting process, particularly when processing Olympus-specific EXIF data structures. When an image file contains malformed or specially constructed EXIF tags that are not adequately validated or sanitized, the mnote_olympus_entry_get_value function attempts to perform mathematical operations involving division by zero, which fundamentally crashes the application or service processing these images. This divide-by-zero error occurs because the code does not properly validate the values within the maker note entries before attempting arithmetic operations, creating an exploitable condition that can be triggered remotely through image processing applications.
The operational impact of this vulnerability extends beyond simple service disruption, as it can affect any application or system that relies on libexif for image metadata processing, including web applications, image viewers, content management systems, and digital asset management platforms. Attackers can leverage this vulnerability by simply uploading or sharing an image file containing the crafted EXIF tags, without requiring any special privileges or complex attack vectors. The denial of service condition can result in complete application crashes, system instability, and potential availability disruptions for legitimate users attempting to process or view images. This vulnerability aligns with CWE-369, which specifically addresses the issue of divide by zero errors in software applications, and represents a classic example of improper input validation that can lead to system instability.
Mitigation strategies for CVE-2012-2837 primarily focus on upgrading to libexif version 0.6.21 or later, where the vulnerability has been addressed through proper input validation and error handling mechanisms. System administrators should also implement additional protective measures such as image sanitization processes that strip or validate EXIF metadata before processing, deployment of web application firewalls that can detect and block malformed image files, and comprehensive testing of image processing pipelines to identify potential exploitation points. The ATT&CK framework categorizes this vulnerability under the T1499.004 technique for Network Denial of Service, as it enables attackers to disrupt services through crafted input data. Organizations should also consider implementing automated patch management systems to ensure timely updates of vulnerable libraries and maintain comprehensive monitoring for suspicious image processing activities that could indicate exploitation attempts.