CVE-2017-6193 in APNGDis
Summary
by MITRE
Buffer overflow in APNGDis 2.8 and earlier allows remote attackers to cause a denial of service and possibly execute arbitrary code via a crafted image containing a malformed image size descriptor in the IHDR chunk.
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Analysis
by VulDB Data Team • 02/02/2025
The vulnerability identified as CVE-2017-6193 represents a critical buffer overflow flaw within APNGDis version 2.8 and earlier implementations. This issue specifically targets the handling of animated portable network graphics files and occurs when processing image size descriptors within the IHDR chunk of png image files. The flaw arises from inadequate input validation and memory management during the parsing of image metadata, creating a condition where maliciously crafted image files can trigger unexpected behavior in the affected software.
The technical exploitation of this vulnerability involves the manipulation of the IHDR chunk's image size descriptor field, which contains critical dimensional information about the png image. When APNGDis processes a crafted image with malformed size parameters, the software fails to properly validate the input data before attempting to allocate memory or perform calculations based on these values. This improper validation leads to a buffer overflow condition where data written beyond the allocated memory boundaries can overwrite adjacent memory regions, potentially corrupting program execution flow and creating opportunities for arbitrary code execution.
From an operational perspective, this vulnerability poses significant risks to systems processing png images, particularly in environments where automated image handling or web-based image processing occurs. Attackers can leverage this flaw to cause denial of service conditions by crashing the target application, or in more sophisticated attacks, potentially execute arbitrary code with the privileges of the affected process. The impact extends beyond simple service disruption as the vulnerability could enable attackers to gain unauthorized access to systems or compromise the integrity of image processing workflows.
The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of improper input validation in image processing libraries. According to ATT&CK framework, this vulnerability could be categorized under T1203, which covers exploitation of remote services, and potentially T1059 for command execution if successful exploitation occurs. The attack surface is particularly concerning in web applications, content management systems, and digital asset management platforms that process user-uploaded png images without proper sanitization.
Mitigation strategies should prioritize immediate patching of affected APNGDis versions to address the buffer overflow condition. Organizations should implement strict input validation for all image files processed by the application, including size parameter verification and memory boundary checks. Network segmentation and access controls can limit the potential impact of exploitation attempts, while monitoring systems should be deployed to detect anomalous image processing activities. Regular security assessments of image processing libraries and automated vulnerability scanning of deployed systems can help identify similar issues in other components of the software stack. The remediation process should also include thorough testing of patched implementations to ensure that the fix does not introduce regressions in legitimate image processing functionality.