CVE-2017-14989 in ImageMagick
Summary
by MITRE
A use-after-free in RenderFreetype in MagickCore/annotate.c in ImageMagick 7.0.7-4 Q16 allows attackers to crash the application via a crafted font file, because the FT_Done_Glyph function (from FreeType 2) is called at an incorrect place in the ImageMagick code.
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Analysis
by VulDB Data Team • 12/30/2022
The vulnerability identified as CVE-2017-14989 represents a critical use-after-free flaw within ImageMagick's rendering engine, specifically in the RenderFreetype function located in MagickCore/annotate.c. This vulnerability affects ImageMagick version 7.0.7-4 Q16 and stems from improper memory management practices during font processing operations. The flaw occurs when the FT_Done_Glyph function from the FreeType 2 library is invoked at an incorrect code location within the ImageMagick codebase, creating a scenario where freed memory can be accessed subsequently by the application.
The technical implementation of this vulnerability involves a classic use-after-free condition where memory allocated for glyph rendering is released prematurely, yet the application continues to reference this memory location during subsequent operations. When processing a crafted font file, the vulnerable code path executes the FT_Done_Glyph function at a point where the memory has already been freed, leading to undefined behavior and application crashes. This memory management error creates a potential exploitation vector where attackers can craft malicious font files that trigger the vulnerable code path, causing denial of service through application crashes or potentially enabling more sophisticated attack vectors if the memory corruption can be leveraged for code execution.
From an operational perspective, this vulnerability poses significant risks to systems that process untrusted font files, particularly in web applications, document processing systems, and content management platforms that utilize ImageMagick for image manipulation. The impact extends beyond simple application crashes as the vulnerability can be exploited remotely through web interfaces that accept image uploads or font processing requests. The flaw aligns with CWE-416, which specifically addresses use-after-free vulnerabilities, and demonstrates how improper memory management in library functions can create cascading security issues. The vulnerability's exploitation potential is further enhanced by the widespread use of ImageMagick across various platforms and applications, making it an attractive target for attackers seeking to disrupt services or establish persistent access points.
The mitigation strategies for CVE-2017-14989 primarily focus on immediate patching of affected ImageMagick installations to version 7.0.7-5 or later, which contains the necessary code modifications to correct the memory management error. System administrators should implement comprehensive input validation and sanitization for all font processing operations, particularly when handling untrusted user uploads. Network segmentation and application whitelisting can help limit the attack surface by restricting access to font processing capabilities. Additionally, implementing sandboxing mechanisms and privilege separation for image processing operations can contain potential exploitation attempts and prevent attackers from leveraging the vulnerability for broader system compromise. Organizations should also consider monitoring for suspicious font file processing activities and implementing automated patch management systems to ensure timely remediation of similar vulnerabilities. The ATT&CK framework categorizes this vulnerability under privilege escalation and denial of service techniques, highlighting the need for comprehensive security controls that address both immediate exploitation risks and long-term system hardening measures.