CVE-2017-12956 in Exiv2
Summary
by MITRE
There is an illegal address access in Exiv2::FileIo::path[abi:cxx11]() in basicio.cpp of libexiv2 in Exiv2 0.26 that will lead to remote denial of service.
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Analysis
by VulDB Data Team • 11/08/2019
The vulnerability identified as CVE-2017-12956 represents a critical flaw in the Exiv2 library's file input/output handling mechanism, specifically within the Exiv2::FileIo::path function located in basicio.cpp. This issue affects Exiv2 version 0.26 and demonstrates a classic case of improper input validation that can be exploited to cause system instability. The flaw manifests as an illegal address access condition that occurs during the processing of file paths, making it particularly dangerous in environments where Exiv2 is used to handle untrusted image metadata.
The technical implementation of this vulnerability stems from inadequate bounds checking and memory management within the file path processing code. When Exiv2 attempts to parse or validate file paths through the Exiv2::FileIo::path function, it fails to properly validate the input parameters before accessing memory locations. This improper validation allows attackers to craft malicious file path inputs that trigger memory access violations, leading to program termination or system crashes. The vulnerability specifically impacts the library's ability to handle malformed or specially crafted file path data, making it a remote denial of service vector when the library processes external input.
From an operational perspective, this vulnerability poses significant risks to applications and systems that rely on Exiv2 for image metadata processing. The remote denial of service condition means that attackers can potentially disrupt services by sending maliciously formatted file paths to applications using Exiv2, causing them to crash or become unresponsive. This affects a wide range of software including image processing applications, web servers handling image uploads, and content management systems that utilize Exiv2 for metadata extraction. The impact extends beyond simple service disruption to potentially compromise the availability of critical image processing functionalities in enterprise environments.
Security professionals should recognize this vulnerability as a variant of CWE-125, which describes out-of-bounds read conditions, and it aligns with ATT&CK technique T1499.004 for network denial of service attacks. The flaw demonstrates poor defensive programming practices and highlights the importance of robust input validation in security-critical libraries. Organizations using Exiv2 should prioritize immediate patching to address this vulnerability, as the remote exploitation potential makes it a high-priority concern for system administrators and security teams responsible for maintaining application availability and stability.
Mitigation strategies should include updating to Exiv2 version 0.27 or later where this vulnerability has been resolved through proper bounds checking and memory validation. Additionally, implementing input sanitization measures at application level can provide defense-in-depth protection, though the primary fix must come from the library itself. Network segmentation and access controls can help limit the potential impact of exploitation attempts, while monitoring systems should be configured to detect unusual application crash patterns that might indicate exploitation attempts. Regular security assessments of third-party libraries and maintaining up-to-date software inventories are essential practices to prevent similar vulnerabilities from affecting organizational security posture.