CVE-2017-9439 in ImageMagick
Summary
by MITRE
In ImageMagick 7.0.5-5, a memory leak was found in the function ReadPDBImage in coders/pdb.c, which allows attackers to cause a denial of service via a crafted file.
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Analysis
by VulDB Data Team • 12/07/2022
The vulnerability identified as CVE-2017-9439 represents a critical memory leak flaw within ImageMagick's processing pipeline that specifically affects version 7.0.5-5. This issue resides within the ReadPDBImage function located in the coders/pdb.c source file, demonstrating how seemingly innocuous file format parsing operations can become vectors for significant system compromise. The vulnerability operates by exploiting improper memory management during the parsing of Portable Document Format files, which are commonly used for document exchange and storage. When an attacker crafts a malicious PDB file and processes it through ImageMagick, the memory leak occurs due to inadequate resource cleanup mechanisms, causing the application to consume increasing amounts of memory over time.
The technical implementation of this vulnerability stems from a fundamental flaw in how ImageMagick handles memory allocation and deallocation during the parsing of PDB image files. The ReadPDBImage function fails to properly release allocated memory blocks when encountering malformed or specially crafted input data, resulting in memory fragmentation and eventual system resource exhaustion. This type of vulnerability falls under CWE-401, which specifically addresses improper release of memory, and aligns with ATT&CK technique T1499.004 for resource exhaustion attacks. The flaw demonstrates a classic case of insufficient input validation combined with poor memory management practices that are common in complex multimedia processing libraries handling multiple file formats.
From an operational perspective, this vulnerability creates significant risk for systems that process untrusted image files, particularly those running ImageMagick as part of web applications, document management systems, or content processing pipelines. Attackers can exploit this weakness by simply uploading or processing a specially crafted PDB file, leading to progressive memory consumption that eventually causes the target system to become unresponsive or crash entirely. The denial of service impact extends beyond individual application failures to potentially affect entire server resources, making it particularly dangerous in cloud environments or multi-tenant systems where resource exhaustion could impact other services. Organizations utilizing ImageMagick for automated processing workflows face the highest risk since these systems may process thousands of files daily, amplifying the potential impact of the memory leak.
Mitigation strategies for CVE-2017-9439 should focus on immediate patching of ImageMagick installations to version 7.0.5-6 or later, which contains the necessary memory management fixes. System administrators should implement strict file validation and sanitization processes, particularly for files originating from untrusted sources, and consider implementing resource limits and monitoring for memory usage patterns. Network-level protections such as file type restrictions and sandboxed processing environments can provide additional defense in depth. Organizations should also conduct regular vulnerability assessments of their ImageMagick deployments and implement automated monitoring for unusual memory consumption patterns that might indicate exploitation attempts. The fix implemented by the ImageMagick development team addresses the root cause by ensuring proper memory deallocation in the ReadPDBImage function, aligning with industry best practices for secure memory management and preventing similar issues in other file format parsers.