CVE-2017-11591 in Exiv2
Summary
by MITRE
There is a Floating point exception in the Exiv2::ValueType function in Exiv2 0.26 that will lead to a remote denial of service attack via crafted input.
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Analysis
by VulDB Data Team • 12/13/2022
The vulnerability identified as CVE-2017-11591 represents a critical floating point exception within the Exiv2 library version 0.26, specifically within the Exiv2::ValueType function. This flaw occurs when the library processes crafted input data that contains malformed floating point values, leading to an unhandled exception that causes the application to terminate abruptly. The issue stems from insufficient input validation and error handling mechanisms within the image metadata processing routines, which are commonly used by applications that read and write image files containing metadata such as jpeg, tiff, and other formats supported by Exiv2.
The technical implementation of this vulnerability involves the Exiv2::ValueType function failing to properly validate floating point number representations during metadata parsing operations. When maliciously crafted input containing invalid or malformed floating point values is processed, the function encounters a division by zero or other arithmetic exception that is not properly caught or handled within the code structure. This behavior aligns with CWE-191, which describes integer underflow conditions, and CWE-369, which covers division by zero errors. The flaw demonstrates poor defensive programming practices where the code does not adequately sanitize input data before processing, creating a path for attackers to inject malformed data that triggers the exception.
From an operational perspective, this vulnerability enables remote denial of service attacks where adversaries can craft specially formatted image files that, when processed by applications using the vulnerable Exiv2 library, will cause those applications to crash or become unresponsive. This affects a wide range of software systems including web applications, content management systems, image processing tools, and digital asset management platforms that rely on Exiv2 for metadata handling. The impact extends beyond simple application crashes as it can be leveraged in broader attack chains where service availability is compromised, affecting business operations and potentially enabling more sophisticated attacks through service disruption.
The attack vector for this vulnerability is particularly concerning as it requires no special privileges or authentication to exploit, making it accessible to any remote attacker who can influence the processing of image files. Applications that automatically process uploaded images or fetch remote images for display are at risk, as the vulnerability can be triggered through normal file processing workflows. The exploitability factor is high due to the predictable nature of the exception and the widespread use of Exiv2 across numerous software platforms and operating systems. Organizations using Exiv2 in their applications should consider implementing input validation at multiple layers, including application-level sanitization, file type verification, and proper exception handling mechanisms to prevent exploitation.
Mitigation strategies for CVE-2017-11591 include immediate patching of Exiv2 library to version 0.27 or later where the floating point exception handling has been corrected. System administrators should also implement network-level controls to restrict processing of untrusted image files, employ sandboxing techniques for image processing operations, and deploy intrusion detection systems that can identify suspicious file processing patterns. Additionally, the implementation of proper error handling and input validation frameworks should be enforced throughout the application stack to prevent similar issues from occurring in other components. Organizations should also consider adopting the ATT&CK framework's T1499 technique for preventing service disruption attacks and implementing proper logging and monitoring to detect exploitation attempts. The vulnerability demonstrates the importance of robust input validation and exception handling in security-critical libraries, particularly those handling user-supplied data in metadata processing contexts.