CVE-2023-29581 in yasm
Summary
by MITRE • 04/12/2023
yasm 1.3.0.55.g101bc was discovered to contain a segmentation violation via the function delete_Token at /nasm/nasm-pp.c.
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Analysis
by VulDB Data Team • 08/01/2024
The vulnerability identified as CVE-2023-29581 affects the yasm assembler version 1.3.0.55.g101bc and represents a critical segmentation fault condition that occurs within the delete_Token function located in the nasm/nasm-pp.c source file. This issue manifests as a memory access violation that can potentially lead to application crashes or system instability when processing malformed input data. The vulnerability specifically targets the preprocessor component of the yasm assembler which is responsible for handling macro expansions and conditional compilation directives. The segmentation fault occurs during token deletion operations when the function attempts to access memory locations that have already been freed or are otherwise inaccessible, creating a classic use-after-free scenario that can be exploited by malicious actors.
The technical flaw stems from improper memory management within the delete_Token function where the code fails to properly validate pointer states before attempting to dereference them during token cleanup operations. This condition falls under the broader category of memory safety issues and can be classified as a CWE-416 use-after-free vulnerability according to the Common Weakness Enumeration standards. The vulnerability demonstrates how improper handling of dynamic memory allocation and deallocation can create exploitable conditions in software systems. When the preprocessor encounters certain malformed or specially crafted input sequences, the delete_Token function is invoked to clean up token structures, but the function does not adequately verify that the memory regions it attempts to access are still valid, leading to the segmentation violation.
The operational impact of this vulnerability extends beyond simple application crashes as it can potentially be leveraged by attackers to execute arbitrary code or cause denial of service conditions within systems that rely on yasm for assembly processing. This is particularly concerning in environments where automated build systems or code analysis tools utilize yasm as part of their processing pipeline, as malicious input could be introduced through compromised source files or build artifacts. The vulnerability affects systems running yasm version 1.3.0.55.g101bc and could be exploited in contexts where untrusted input is processed through the assembler's preprocessor functionality. Attackers might craft malicious assembly files or input sequences that trigger the vulnerable code path, potentially leading to system compromise or service disruption in build environments and automated code processing systems.
Mitigation strategies for this vulnerability should prioritize immediate patching of affected yasm installations to version 1.3.0.55.g101bc or later where the memory management issues have been resolved. System administrators should implement strict input validation procedures for any assembly code processed through yasm, particularly in automated build environments where untrusted inputs might be encountered. The fix typically involves proper pointer validation and memory state checks within the delete_Token function to prevent access to freed memory regions. Organizations should also consider implementing runtime protections such as address space layout randomization and stack canaries to reduce the exploitability of similar memory corruption vulnerabilities. From an ATT&CK framework perspective, this vulnerability aligns with techniques involving memory corruption and privilege escalation, specifically targeting the PREPROCESSOR component of assembly tools and potentially enabling more sophisticated attacks through system compromise or denial of service conditions in build and development environments.