CVE-2020-23907 in retdec
Summary
by MITRE • 04/22/2021
An issue was discovered in retdec v3.3. In function canSplitFunctionOn() of ir_modifications.cpp, there is a possible out of bounds read due to a heap buffer overflow. The impact is: Deny of Service, Memory Disclosure, and Possible Code Execution.
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Analysis
by VulDB Data Team • 04/28/2021
The vulnerability identified as CVE-2020-23907 resides within the retdec decompiler version 3.3, specifically within the ir_modifications.cpp source file at the canSplitFunctionOn() function implementation. This issue represents a critical heap buffer overflow condition that stems from inadequate bounds checking during memory operations. The flaw manifests when the decompiler processes certain input binaries, particularly those containing complex control flow structures or malformed function definitions that trigger the function splitting logic.
The technical root cause of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions where an application accesses memory beyond the bounds of a buffer. In this case, the heap buffer overflow occurs because the canSplitFunctionOn() function does not properly validate array indices or buffer limits when iterating through function control flow graphs. The vulnerability exploits a scenario where the decompiler attempts to analyze function boundaries and determine optimal split points, leading to memory access violations that can occur at runtime when processing malformed input files.
The operational impact of this vulnerability extends beyond simple denial of service to encompass more severe consequences including memory disclosure and potential code execution. When exploited, the heap buffer overflow can cause the decompiler to read memory locations outside of intended buffer boundaries, potentially exposing sensitive data from adjacent memory regions. This memory disclosure capability can reveal stack contents, heap metadata, or other confidential information that may aid in further exploitation attempts. The possibility of code execution arises from the nature of heap corruption, which can be leveraged to manipulate program control flow through techniques such as return-oriented programming or function pointer overwrites.
From an adversarial perspective, this vulnerability maps to several ATT&CK tactics including execution through malicious input processing, privilege escalation via memory corruption, and defense evasion through process manipulation. Attackers could craft specially designed binary files that trigger this vulnerability when processed by retdec, potentially leading to unauthorized code execution on systems running the affected decompiler version. The vulnerability's impact is particularly concerning in security research environments where decompilers are frequently used to analyze potentially malicious code, as it could be exploited to gain unauthorized access to analysis environments.
Mitigation strategies for this vulnerability require immediate patching of retdec to version 3.4 or later, which includes the necessary bounds checking fixes in the ir_modifications.cpp file. Organizations should also implement input validation measures when processing binary files through the decompiler, including sandboxing execution environments and restricting access to potentially malicious inputs. Additionally, system administrators should monitor for any unauthorized decompiler usage and implement network segmentation to limit potential attack vectors. The vulnerability demonstrates the importance of thorough input validation in decompilation tools and highlights the need for robust memory safety practices in reverse engineering software to prevent exploitation through heap-based memory corruption attacks.