CVE-2022-29693 in Engine
Summary
by MITRE • 06/02/2022
Unicorn Engine v2.0.0-rc7 and below was discovered to contain a memory leak via the function uc_close at /my/unicorn/uc.c.
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Analysis
by VulDB Data Team • 06/06/2022
The vulnerability identified as CVE-2022-29693 affects the Unicorn Engine version 2.0.0-rc7 and earlier releases, representing a critical memory management flaw that compromises system stability and resource utilization. This issue manifests through the uc_close function located in the /my/unicorn/uc.c source file, where improper memory deallocation occurs during engine shutdown procedures. The Unicorn Engine serves as a lightweight multi-platform CPU emulator that enables developers to execute code in different architectures, making it a widely adopted component in security research, malware analysis, and emulation frameworks. The memory leak vulnerability specifically impacts applications that rely on the engine's cleanup functionality, creating potential for progressive resource exhaustion and system performance degradation over time.
The technical flaw stems from inadequate memory deallocation within the uc_close function which is responsible for terminating emulation sessions and releasing allocated resources. When this function is invoked to close an emulation context, it fails to properly free all allocated memory blocks, resulting in memory leaks that accumulate with each engine instance closure. This memory management deficiency creates a persistent resource drain that can lead to system instability, particularly in long-running applications or environments where multiple emulation sessions are frequently initiated and terminated. The vulnerability represents a classic memory leak pattern that can be exploited to consume system resources and potentially cause denial of service conditions, with the severity increasing based on the frequency of engine usage and the scale of memory allocations required for each emulation session.
The operational impact of this vulnerability extends beyond simple resource consumption, affecting the reliability and security posture of systems that depend on the Unicorn Engine. Applications utilizing this emulation framework may experience progressive performance degradation, system slowdowns, or complete system crashes when memory leaks accumulate to critical levels. Security researchers and malware analysts who rely on the engine for dynamic analysis and reverse engineering activities face increased risk of operational interruptions, potentially compromising their analysis processes and timelines. The vulnerability is particularly concerning in automated environments where emulation sessions are frequently created and destroyed, as the cumulative effect of memory leaks can rapidly exhaust available system resources and lead to unexpected application termination or system instability.
Mitigation strategies for CVE-2022-29693 should prioritize immediate upgrade to Unicorn Engine version 2.0.0-rc8 or later, which contains the necessary patches to address the memory leak in the uc_close function. System administrators and developers should implement comprehensive monitoring of memory usage patterns in applications utilizing the engine to detect potential leak accumulation before it leads to operational issues. Additionally, defensive programming practices such as implementing periodic memory diagnostics and resource cleanup verification can help identify and mitigate the impact of similar memory management issues. The vulnerability aligns with CWE-401, which categorizes memory leaks as a common weakness in software design, and may be relevant to ATT&CK technique T1566 related to credential dumping and system reconnaissance activities that could be amplified by resource exhaustion. Organizations should also consider implementing application sandboxing and resource limits to prevent memory leak exploitation from causing broader system impact, particularly in environments where emulation frameworks are used extensively for security analysis and penetration testing activities.