Heap Out-of-Bounds Read in Assimp MD2Importer

Executive Summary

This vulnerability is a heap out-of-bounds read in the Assimp library's MD2 importer (MD2Importer::InternReadFile). It occurs when processing MD2 files with a crafted frame size that exceeds the file's boundaries. The issue stems from using an unvalidated stored frameSize header field, allowing attackers to read past the file buffer. When a non-zero keyframe is selected, a malicious file can place vertices beyond the buffer's end, causing crashes or leaking adjacent heap memory.

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Detection Guidance

Detecting this vulnerability requires analyzing Assimp's MD2 file processing. Use AddressSanitizer during compilation to detect heap-buffer-overflows when processing .md2 files. Monitor application crashes when loading MD2 files with non-zero keyframes. Check for heap memory leaks or corruption in logs when processing suspicious files.

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Impact Analysis

This vulnerability can impact users by causing application crashes when processing maliciously crafted MD2 files. It may also lead to disclosure of adjacent heap memory, potentially exposing sensitive data. Attackers could exploit this to trigger denial-of-service conditions or, in some cases, execute arbitrary code depending on the system configuration.

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Compliance Impact

This vulnerability could impact compliance with GDPR and HIPAA by potentially exposing sensitive data through heap memory leaks. If exploited, it may lead to unauthorized disclosure of personal or health information, violating data protection requirements. Organizations processing such data must address this flaw to maintain compliance.

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Mitigation Strategies

Upgrade Assimp to a patched version that validates frameSize in MD2Importer::ValidateHeader(). Avoid processing untrusted MD2 files. If using Assimp, disable MD2 import support via configuration. Monitor for crashes or memory corruption when loading MD2 files.

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