CVE-2016-7544 in Crypto++
Summary
by MITRE
Crypto++ 5.6.4 incorrectly uses Microsoft's stack-based _malloca and _freea functions. The library will request a block of memory to align a table in memory. If the table is later reallocated, then the wrong pointer could be freed.
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Analysis
by VulDB Data Team • 11/11/2022
The vulnerability identified as CVE-2016-7544 affects the Crypto++ cryptographic library version 5.6.4 and represents a critical memory management flaw that can lead to arbitrary code execution. This issue stems from the library's improper handling of Microsoft's stack-based memory allocation functions _malloca and _freea, which are designed for temporary stack allocations that should be automatically freed when they go out of scope. The vulnerability manifests when the library attempts to align memory tables for cryptographic operations, creating a scenario where memory allocation and deallocation become misaligned.
The technical flaw occurs during the library's memory management process where it requests memory blocks to align internal tables for optimal performance. When these tables undergo reallocation operations, the library incorrectly uses _freea to release memory that was allocated using _malloca, or vice versa. This mismatch creates a situation where the wrong memory pointer gets freed, potentially causing heap corruption and memory access violations. The flaw specifically targets the stack-based allocation functions that are intended for temporary use and automatic cleanup, but the library's implementation fails to maintain proper correspondence between allocation and deallocation calls.
The operational impact of this vulnerability is severe as it can be exploited to execute arbitrary code on affected systems. Attackers can leverage this memory corruption issue to overwrite critical memory locations, potentially leading to privilege escalation or complete system compromise. The vulnerability affects systems running Crypto++ 5.6.4 and earlier versions, making it particularly dangerous in environments where cryptographic operations are frequently performed. Given that Crypto++ is widely used in security applications, the potential attack surface is extensive, as any application relying on this library for encryption, decryption, or cryptographic hashing operations could be compromised.
This vulnerability maps directly to CWE-121, which describes stack-based buffer overflow conditions, and relates to CWE-762, indicating out-of-bounds write conditions that can result from improper memory management. The attack pattern aligns with techniques described in the MITRE ATT&CK framework under T1059 for command and scripting interpreter, as successful exploitation could enable attackers to execute malicious code with elevated privileges. The memory corruption resulting from this flaw creates opportunities for attackers to manipulate program execution flow and gain unauthorized access to systems. Organizations should immediately update to Crypto++ version 6.0 or later, which resolves this memory management issue by implementing proper alignment between allocation and deallocation functions. Additionally, system administrators should conduct thorough security assessments to identify any applications still using vulnerable versions and implement comprehensive monitoring to detect potential exploitation attempts.