CVE-2017-17723 in Exiv2
Summary
by MITRE
In Exiv2 0.26, there is a heap-based buffer over-read in the Exiv2::Image::byteSwap4 function in image.cpp. Remote attackers can exploit this vulnerability to disclose memory data or cause a denial of service via a crafted TIFF file.
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Analysis
by VulDB Data Team • 02/06/2023
The vulnerability identified as CVE-2017-17723 represents a critical heap-based buffer over-read flaw within the Exiv2 image processing library version 0.26. This issue resides in the Exiv2::Image::byteSwap4 function located in the image.cpp source file, making it a fundamental component of the library's image handling capabilities. The flaw manifests when processing TIFF formatted image files, specifically targeting the byte swapping operations that are essential for proper image data interpretation across different system architectures. This vulnerability falls under the Common Weakness Enumeration category CWE-125, which specifically addresses out-of-bounds read conditions that can lead to information disclosure or system instability. The security implications are particularly severe given that Exiv2 is widely used across various applications and platforms for metadata extraction and image processing tasks.
The technical exploitation of this vulnerability occurs when a remote attacker crafts a malicious TIFF file that triggers the byteSwap4 function with malformed data structures. During the processing of such crafted files, the function attempts to read memory locations beyond the allocated buffer boundaries, resulting in a heap-based buffer over-read condition. This over-read allows attackers to potentially access sensitive memory data that may contain confidential information, application state details, or other system-related data that should remain private. The vulnerability is particularly concerning because it can be exploited remotely through web applications, file sharing systems, or any service that processes user-provided TIFF files without proper input validation. The denial of service aspect of this vulnerability means that even if memory disclosure is not achieved, the system can be made unavailable through controlled crashes or resource exhaustion.
The operational impact of CVE-2017-17723 extends across multiple domains where Exiv2 is integrated, including web applications, content management systems, digital asset management platforms, and security tools that rely on proper image metadata handling. Attackers can leverage this vulnerability to gain unauthorized access to memory contents that might include authentication tokens, cryptographic keys, or other sensitive data stored in adjacent memory regions. The attack surface is particularly broad since TIFF files are commonly used in professional photography, publishing, and document management systems where users might unknowingly trigger the vulnerability through routine file processing activities. This vulnerability aligns with ATT&CK technique T1059.007 for remote code execution through file processing, and can be classified under the broader category of information disclosure attacks that compromise system confidentiality.
Mitigation strategies for CVE-2017-17723 require immediate patching of Exiv2 library versions prior to 0.27, as the vulnerability was addressed in subsequent releases. System administrators should implement strict input validation and sanitization for all TIFF file processing activities, particularly in web-facing applications where user uploads are accepted. Network segmentation and application whitelisting can help reduce the attack surface by limiting which systems can process potentially malicious image files. Additional protective measures include implementing sandboxing techniques for image processing operations, using memory protection mechanisms such as stack canaries, and deploying intrusion detection systems that can identify suspicious file processing patterns. Organizations should also consider implementing automated vulnerability scanning tools that can detect and block known vulnerable versions of Exiv2 in their environments, ensuring that all systems processing image metadata are updated to patched versions that address this heap-based buffer over-read condition.