CVE-2017-8400 in SWFTools
Summary
by MITRE
In SWFTools 0.9.2, an out-of-bounds write of heap data can occur in the function png_load() in lib/png.c:755. This issue can be triggered by a malformed PNG file that is mishandled by png2swf. Attackers could exploit this issue for DoS; it might cause arbitrary code execution.
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Analysis
by VulDB Data Team • 12/02/2022
The vulnerability identified as CVE-2017-8400 represents a critical out-of-bounds write condition within SWFTools version 0.9.2, specifically within the png_load() function located in lib/png.c at line 755. This flaw manifests when processing malformed PNG files through the png2swf utility, creating a scenario where heap data becomes corrupted through improper memory management. The issue stems from insufficient bounds checking during the parsing of PNG image data structures, allowing attackers to craft specially crafted files that trigger memory corruption during the conversion process.
The technical nature of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a classic example of improper input validation in multimedia processing libraries. When the png2swf tool encounters a malformed PNG file, the png_load() function fails to properly validate array indices or buffer boundaries before writing data to allocated memory regions. This lack of proper bounds checking enables attackers to manipulate memory layout and potentially overwrite adjacent heap data structures, leading to unpredictable behavior and system instability.
From an operational perspective, this vulnerability presents significant risks to systems that process untrusted PNG files through SWFTools, particularly in environments where automated conversion of user-uploaded content occurs. The potential for denial of service attacks is substantial as the out-of-bounds write can cause the application to crash or become unresponsive, while the possibility of arbitrary code execution creates a more severe threat vector. Attackers could leverage this vulnerability to execute malicious code on vulnerable systems, potentially escalating privileges or establishing persistent access points within network environments. The impact extends beyond simple application crashes to encompass broader system compromise scenarios.
Mitigation strategies for CVE-2017-8400 should prioritize immediate software updates to versions that address the buffer overflow condition in SWFTools. Organizations should implement strict input validation procedures for all PNG files processed through SWFTools, including the use of checksums and file format verification before conversion operations. Network segmentation and application whitelisting can help limit the attack surface, while regular security assessments should verify that no other vulnerable components exist within the processing pipeline. The vulnerability also highlights the importance of following secure coding practices and implementing proper memory management techniques as outlined in the software security development lifecycle frameworks, particularly emphasizing the need for bounds checking and input validation in multimedia processing applications.