CVE-2017-15277 in ImageMagick
Summary
by MITRE
ReadGIFImage in coders/gif.c in ImageMagick 7.0.6-1 and GraphicsMagick 1.3.26 leaves the palette uninitialized when processing a GIF file that has neither a global nor local palette. If the affected product is used as a library loaded into a process that operates on interesting data, this data sometimes can be leaked via the uninitialized palette.
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Analysis
by VulDB Data Team • 01/03/2023
CVE-2017-15277 represents a critical information disclosure vulnerability affecting ImageMagick 7.0.6-1 and GraphicsMagick 1.3.26 where the ReadGIFImage function in coders/gif.c fails to properly initialize the palette structure when processing GIF files lacking both global and local palettes. This uninitialized memory condition creates a pathway for sensitive data to be inadvertently exposed through the palette buffer, as the function does not adequately clear or reset memory before use. The vulnerability stems from improper memory management practices where the application assumes that memory allocated for palette data will be properly initialized, but in cases where palette information is absent from the input file, the memory retains its previous contents.
The technical flaw manifests when ImageMagick or GraphicsMagick processes malformed GIF files that contain no palette information, either globally or locally defined within the image structure. The ReadGIFImage function allocates memory for palette data but fails to initialize it completely, leaving remnants of previously processed data in memory. This uninitialized palette memory can contain sensitive information such as cryptographic keys, user credentials, session tokens, or other confidential data that was previously stored in the same memory locations. The vulnerability is particularly concerning because it operates silently without alerting the user or system administrator, making detection difficult and potentially allowing for prolonged data exposure.
When these affected libraries are integrated into applications that process untrusted GIF files, the operational impact extends beyond simple information disclosure to potentially enable more sophisticated attacks. An attacker who can control or influence the input GIF files can leverage this vulnerability to extract sensitive data from the memory space of the processing application. This type of vulnerability aligns with CWE-457: Use of Uninitialized Variable and falls under the broader category of memory safety issues. The attack vector typically involves sending specially crafted GIF files to applications that utilize these libraries, such as web applications, content management systems, or file processing services. The vulnerability is particularly dangerous in environments where the processing application has access to sensitive data, as the uninitialized palette memory may contain information from previous operations within the same process.
The exploitation of this vulnerability requires careful consideration of the target environment and the memory layout of the affected processes. According to ATT&CK framework, this represents a technique for privilege escalation and information gathering through memory corruption vulnerabilities. Organizations using affected versions of ImageMagick or GraphicsMagick should prioritize immediate patching to address the uninitialized memory handling issue. The recommended mitigations include upgrading to patched versions of both ImageMagick and GraphicsMagick, implementing proper input validation and sanitization for GIF file processing, and configuring applications to restrict file processing capabilities where possible. Additionally, organizations should consider implementing memory protection mechanisms such as stack canaries, address space layout randomization, and heap-based memory protection to reduce the potential impact of similar uninitialized memory vulnerabilities. The vulnerability underscores the importance of proper memory initialization practices and highlights the need for comprehensive security testing of image processing libraries that handle untrusted input data.