CVE-2018-11037 in Exiv2
Summary
by MITRE
In Exiv2 0.26, the Exiv2::PngImage::printStructure function in pngimage.cpp allows remote attackers to cause an information leak via a crafted file.
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Analysis
by VulDB Data Team • 03/13/2023
The vulnerability identified as CVE-2018-11037 affects Exiv2 version 0.26, a widely used C++ library for reading and writing image metadata. This issue resides within the Exiv2::PngImage::printStructure function located in the pngimage.cpp source file, representing a critical information disclosure flaw that can be exploited remotely through specially crafted image files. The vulnerability stems from insufficient input validation and improper handling of malformed PNG image structures during metadata analysis operations.
The technical flaw manifests when the printStructure function processes PNG image files without adequate bounds checking or sanitization of input data. When attackers submit maliciously constructed PNG files containing crafted metadata or corrupted image headers, the function fails to properly validate the structure before attempting to parse and display the image information. This improper handling creates a scenario where sensitive memory contents from the application process may be inadvertently exposed to remote attackers through the information leak mechanism. The vulnerability operates at the application level and requires no special privileges to exploit, making it particularly dangerous in environments where Exiv2 is used to process untrusted image files from external sources.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can potentially expose sensitive data that might include memory addresses, internal application state, or other confidential information that could aid attackers in subsequent exploitation attempts. Remote attackers can leverage this vulnerability by simply providing a crafted PNG file to any application that utilizes Exiv2 for image processing, without requiring any authentication or specific user interaction. This makes the vulnerability particularly attractive to threat actors seeking to gather intelligence about target systems or applications that rely on Exiv2 for metadata handling. The information leak could potentially reveal memory layout details that might assist in bypassing security mitigations like ASLR or provide insights into the internal workings of the vulnerable application.
Organizations using Exiv2 version 0.26 should immediately implement mitigations including upgrading to a patched version of the library where available, implementing strict input validation for all image files processed through Exiv2, and deploying network-based restrictions that limit exposure to untrusted image content. The vulnerability aligns with CWE-200, which specifically addresses improper handling of information exposure, and could potentially be leveraged as part of a broader attack chain that might include privilege escalation or further exploitation techniques. Security practitioners should also consider implementing monitoring and alerting mechanisms to detect unusual patterns in metadata processing that might indicate exploitation attempts. Additionally, the vulnerability demonstrates the importance of proper input validation in image processing libraries, as it highlights how seemingly benign metadata parsing operations can become attack vectors when proper security controls are not implemented.
This vulnerability represents a classic example of how metadata processing libraries can become security risks when they fail to properly validate input data structures. The flaw underscores the need for robust defensive programming practices in image processing components and demonstrates that even libraries primarily designed for metadata extraction can become attack vectors when they process untrusted input without adequate sanitization mechanisms. The remote exploitability of this vulnerability makes it particularly concerning for web applications, content management systems, and any platform that accepts user-uploaded images for processing with Exiv2 functionality.