CVE-2017-12935 in GraphicsMagick
Summary
by MITRE
The ReadMNGImage function in coders/png.c in GraphicsMagick 1.3.26 mishandles large MNG images, leading to an invalid memory read in the SetImageColorCallBack function in magick/image.c.
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Analysis
by VulDB Data Team • 12/16/2022
The vulnerability identified as CVE-2017-12935 represents a critical memory safety issue within GraphicsMagick version 1.3.26, specifically affecting the handling of Multiple Network Graphics format files. This flaw exists in the ReadMNGImage function located in the coders/png.c module, where improper validation of large MNG image structures leads to exploitable memory access violations. The issue manifests when the software processes malformed or oversized MNG files, creating conditions where memory is accessed beyond allocated boundaries during image processing operations.
The technical root cause of this vulnerability stems from inadequate input validation and boundary checking within the MNG image parsing logic. When GraphicsMagick encounters a large MNG image, the ReadMNGImage function fails to properly validate the image dimensions and data structures before proceeding with memory allocation and data processing. This deficiency allows an attacker to craft specially formatted MNG files that trigger an invalid memory read condition in the SetImageColorCallBack function within the magick/image.c module. The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and represents a classic example of insufficient bounds checking in image processing libraries. The flaw operates at the intersection of memory corruption and image format parsing, creating a path for potential arbitrary code execution or denial of service attacks.
The operational impact of CVE-2017-12935 extends beyond simple memory corruption, as it can be exploited in various attack scenarios including remote code execution when GraphicsMagick is used in web applications, file processing services, or automated image handling systems. The vulnerability is particularly dangerous in environments where users can upload or process untrusted image files, as it allows attackers to craft malicious MNG files that can cause system crashes or potentially execute arbitrary code with the privileges of the running GraphicsMagick process. This makes the flaw especially concerning for web applications, content management systems, and digital asset management platforms that rely on GraphicsMagick for image processing operations. The ATT&CK framework categorizes this vulnerability under T1203, which involves legitimate program execution, as it exploits legitimate image processing functionality to achieve malicious objectives.
Mitigation strategies for CVE-2017-12935 primarily focus on immediate software updates and input validation measures. The most effective solution involves upgrading to GraphicsMagick version 1.3.27 or later, where the vulnerability has been patched through enhanced input validation and proper boundary checking mechanisms. Organizations should also implement strict file validation policies, including MIME type checking, file size limitations, and content scanning for potentially malicious image files. Additional protective measures include running GraphicsMagick with restricted privileges, implementing sandboxing techniques, and deploying network monitoring to detect unusual file processing patterns that might indicate exploitation attempts. The vulnerability serves as a reminder of the critical importance of robust input validation in multimedia processing libraries and demonstrates how seemingly benign image format handling can become a significant security risk when proper boundary checking is omitted.