CVE-2018-14524 in LibreDWG
Summary
by MITRE
dwg_decode_eed in decode.c in GNU LibreDWG 0.5.1048 leads to a double free (in dwg_free_eed in free.c) because it does not properly manage the obj->eed value after a free occurs.
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Analysis
by VulDB Data Team • 04/25/2023
This vulnerability exists in GNU LibreDWG version 0.5.1048 within the dwg_decode_eed function located in decode.c. The flaw represents a classic double free vulnerability that occurs when the function fails to properly manage memory references after a free operation has been executed. The specific issue manifests when the obj->eed value is not correctly handled following a memory deallocation, creating conditions where the same memory location can be freed twice. This memory management error directly impacts the dwg_free_eed function in free.c which is responsible for cleaning up extended entity data structures. The vulnerability stems from inadequate pointer management and memory state tracking within the DWG file parsing library, which processes AutoCAD drawing files. When processing malformed or specially crafted DWG files, the library can trigger this double free condition, potentially leading to memory corruption and system instability.
The technical implications of this vulnerability align with CWE-415, which addresses double free conditions in memory management, and CWE-416, which covers use after free errors. This type of vulnerability falls under the ATT&CK technique T1059.007 for command and scripting interpreter, as it could potentially be exploited through malicious file execution. The operational impact extends beyond simple memory corruption since this vulnerability could enable arbitrary code execution in contexts where the library is used to process untrusted DWG files. Attackers could craft malicious DWG files that, when opened by applications using GNU LibreDWG, trigger the double free condition and potentially achieve remote code execution or system compromise. The vulnerability affects any application that relies on LibreDWG for DWG file processing, including CAD software, document viewers, and automated processing systems. This issue particularly concerns users who handle DWG files from untrusted sources or those operating in environments where file validation is insufficient.
Mitigation strategies should focus on immediate patching of the GNU LibreDWG library to version 0.5.1049 or later, which contains the necessary memory management fixes. System administrators should implement strict file validation procedures for DWG files, particularly those received from external sources or through untrusted channels. Applications using LibreDWG should incorporate additional memory safety checks and implement proper error handling for file parsing operations. The fix addresses the core issue by ensuring proper pointer management and preventing the double free condition through improved memory state tracking. Organizations should also consider implementing sandboxing mechanisms for DWG file processing and monitoring for unusual memory allocation patterns. Regular security audits of third-party libraries and components should be conducted to identify similar memory management vulnerabilities. The vulnerability demonstrates the critical importance of proper memory management in parsing libraries and highlights the need for comprehensive testing of edge cases in file format processing software. Security teams should monitor for exploitation attempts targeting this vulnerability in environments where LibreDWG is deployed, particularly in networked systems or applications handling user-uploaded content.