CVE-2018-7871 in libming
Summary
by MITRE
There is a heap-based buffer over-read in the getName function of util/decompile.c in libming 0.4.8 for CONSTANT16 data. A crafted input will lead to a denial of service or possibly unspecified other impact.
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Analysis
by VulDB Data Team • 02/17/2023
The vulnerability identified as CVE-2018-7871 represents a critical heap-based buffer over-read flaw within the libming library version 0.4.8, specifically affecting the getName function in the util/decompile.c file. This issue manifests when processing CONSTANT16 data structures, which are commonly encountered in SWF (Small Web Format) file parsing operations. The libming library serves as a powerful tool for parsing and generating SWF files, making it a widely used component in various multimedia applications and security analysis tools. The vulnerability stems from inadequate bounds checking during the processing of structured data within the decompilation routine, creating an exploitable condition that can be triggered by malformed input files.
The technical implementation of this vulnerability involves the getName function's handling of CONSTANT16 data elements, where insufficient validation allows for memory access beyond the allocated buffer boundaries. When a crafted input containing malformed CONSTANT16 data is processed, the function attempts to read memory locations that extend beyond the intended buffer limits, resulting in a heap-based buffer over-read condition. This flaw operates under CWE-125, which categorizes improper bounds checking as a fundamental weakness in memory safety. The vulnerability's impact extends beyond simple denial of service, as the over-read behavior can potentially expose sensitive memory contents or trigger unpredictable program execution patterns, making it a serious concern for systems processing untrusted SWF content.
From an operational perspective, this vulnerability creates significant risks for applications that utilize libming for SWF file analysis, particularly in security contexts where threat intelligence systems process potentially malicious Flash content. The denial of service impact can disrupt legitimate operations by causing application crashes or resource exhaustion, while the unspecified other impacts suggest potential for more severe consequences including information disclosure or execution of arbitrary code. Attackers could leverage this vulnerability by crafting specially designed SWF files that, when processed by vulnerable applications, would trigger the buffer over-read condition and potentially compromise system integrity. This vulnerability directly aligns with ATT&CK technique T1059.007, which covers scripting languages and command and control communications, particularly when considering the exploitation of SWF-based attack vectors.
The mitigation strategy for CVE-2018-7871 requires immediate application of the vendor-provided patch or upgrade to libming version 0.4.9, which includes proper bounds checking mechanisms for the getName function. System administrators should implement input validation measures to filter or reject malformed SWF files before processing them through libming-based applications. Additionally, organizations should consider implementing network segmentation and content filtering to prevent the delivery of potentially malicious SWF content to systems that rely on libming for file processing. The vulnerability highlights the importance of memory safety practices in legacy codebases and demonstrates the ongoing need for rigorous input validation in multimedia processing libraries. Security monitoring should include detection of异常 memory access patterns and unusual application behavior that might indicate exploitation attempts, with particular attention to systems processing Flash content from untrusted sources.