CVE-2017-11336 in Exiv2
Summary
by MITRE
There is a heap-based buffer over-read in the Image::printIFDStructure function in image.cpp 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 • 10/26/2019
The vulnerability identified as CVE-2017-11336 represents a critical heap-based buffer over-read condition within the Exiv2 image processing library version 0.26. This flaw exists specifically within the Image::printIFDStructure function located in the image.cpp source file, where improper input validation allows attackers to craft malicious image files that trigger memory access violations. The vulnerability stems from insufficient bounds checking when processing image metadata structures, particularly those following the International Fixed Document (IFD) format commonly used in image files such as TIFF and JPEG. When an attacker provides a specially crafted input file containing malformed IFD data, the function attempts to read memory beyond the allocated buffer boundaries, potentially causing application crashes or system instability.
The technical implementation of this vulnerability involves the improper handling of image metadata parsing operations where the Image::printIFDStructure function processes directory entries without adequate validation of the input data length. This condition creates a scenario where the program reads beyond the intended memory allocation, accessing adjacent memory regions that may contain sensitive data or cause unpredictable behavior. The heap-based nature of the over-read indicates that the vulnerability occurs within dynamically allocated memory segments, making the exploitation more complex but potentially more severe than stack-based buffer overflows. This type of vulnerability typically falls under CWE-125: "Out-of-bounds Read" and represents a classic example of memory safety issues that can lead to denial of service conditions when properly crafted malicious inputs are processed.
From an operational perspective, this vulnerability poses significant risks to applications and systems that rely on Exiv2 for image metadata processing, particularly those handling untrusted user uploads or third-party image files. Remote denial of service attacks can be executed by simply providing a maliciously crafted image file to any application that uses Exiv2 for image processing, potentially affecting web applications, content management systems, digital asset management platforms, and image processing services. The impact extends beyond simple service disruption as the vulnerability could potentially be leveraged to extract sensitive information from memory or serve as a precursor to more sophisticated attacks. This aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter: PowerShell and T1499.004 for Endpoint Denial of Service, demonstrating how such vulnerabilities can be weaponized in broader attack chains.
The recommended mitigation strategies for CVE-2017-11336 include immediate upgrading to Exiv2 version 0.27 or later, where the buffer over-read issue has been addressed through proper bounds checking and input validation. Organizations should also implement input sanitization measures at the application level, including validating image file integrity before processing and implementing proper error handling for malformed metadata. Network-level protections such as web application firewalls and content filtering systems can help detect and block malicious image files before they reach vulnerable applications. Additionally, implementing proper memory protection mechanisms including stack canaries, address space layout randomization, and heap hardening techniques can provide additional defense-in-depth measures. Regular security assessments and vulnerability scanning should be conducted to identify any other potentially affected systems using older versions of the Exiv2 library, as this vulnerability affects a widely used image processing component in numerous open source and commercial applications across various platforms and operating systems.