CVE-2017-6192 in APNGDis
Summary
by MITRE
Buffer overflow in APNGDis 2.8 and earlier allows a remote attackers to cause denial of service and possibly execute arbitrary code via a crafted image containing a malformed chunk size descriptor.
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Analysis
by VulDB Data Team • 02/02/2025
The vulnerability identified as CVE-2017-6192 represents a critical buffer overflow flaw within APNGDis version 2.8 and earlier implementations. This vulnerability specifically targets the handling of animated portable network graphics files, which are an extension of the standard png format that supports animation and transparency. The flaw occurs when the application processes image files containing malformed chunk size descriptors that exceed the expected buffer boundaries. The affected software fails to properly validate the size parameters within the png chunk headers, creating an opportunity for malicious actors to exploit memory corruption vulnerabilities. This issue falls under the CWE-121 buffer overflow category, which specifically addresses the condition where a program writes data beyond the boundaries of a fixed-length buffer. The vulnerability demonstrates characteristics consistent with CWE-787, which describes out-of-bounds writes that can occur when programs do not properly check array indices or buffer limits.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enable remote code execution capabilities. When a remote attacker crafts a malicious image file with malformed chunk descriptors, the APNGDis application becomes vulnerable to memory corruption that could be leveraged to execute arbitrary code on the target system. This represents a significant security risk as the vulnerability can be triggered through simple file processing operations without requiring user interaction beyond opening the malicious file. The attack surface is particularly concerning given that png and apng files are commonly encountered in web browsers, image viewers, and various multimedia applications. The vulnerability's exploitability is enhanced by the fact that it can be triggered remotely through web-based delivery mechanisms, making it particularly dangerous in environments where users may encounter malicious image files through web browsing or email attachments.
From an attack framework perspective, this vulnerability aligns with several ATT&CK techniques including T1059 command and scripting interpreter and T1203 exploit public-facing application, as it represents an unauthenticated remote code execution vector through the exploitation of a public-facing image processing application. The vulnerability demonstrates the classic attack pattern where an attacker crafts a malicious payload that, when processed by vulnerable software, results in arbitrary code execution. The buffer overflow occurs during the parsing phase of the png file structure where the application reads chunk size descriptors without proper bounds checking. This processing stage is particularly vulnerable because it occurs early in the file parsing sequence, before any additional validation or sanitization occurs. The vulnerability is particularly concerning from a defensive standpoint as it can be exploited through multiple vectors including web browsers, desktop image viewers, and server-side image processing applications that handle user-uploaded content. The exploitation requires minimal sophistication and can be automated, making it attractive to threat actors seeking to compromise systems through file-based attacks.
Mitigation strategies for this vulnerability require immediate patching of affected APNGDis versions to address the buffer overflow in chunk size descriptor handling. Organizations should implement strict file validation policies that reject or sanitize image files before processing, particularly in environments where user-uploaded content is processed. The vulnerability can be addressed through input validation techniques that enforce strict bounds checking on chunk size parameters and implement proper memory management practices. Security teams should also consider implementing network-based protections such as web application firewalls that can detect and block malicious image files. The patching process should be prioritized across all systems running affected versions of APNGDis, including desktop applications, web servers, and any image processing services that may be vulnerable to this attack vector. Additionally, organizations should conduct comprehensive vulnerability assessments to identify all systems that may be running vulnerable versions of the software and ensure that proper security controls are in place to prevent exploitation of this and similar buffer overflow vulnerabilities in image processing applications.