CVE-2019-14248 in Netwide Assembler
Summary
by MITRE
In libnasm.a in Netwide Assembler (NASM) 2.14.xx, asm/pragma.c allows a NULL pointer dereference in process_pragma, search_pragma_list, and nasm_set_limit when "%pragma limit" is mishandled.
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Analysis
by VulDB Data Team • 11/06/2023
The vulnerability identified as CVE-2019-14248 resides within the Netwide Assembler (NASM) version 2.14.xx, specifically in the libnasm.a library component. This issue manifests as a NULL pointer dereference occurring in multiple functions within the asm/pragma.c file when processing malformed "%pragma limit" directives. The vulnerability represents a critical security flaw that can potentially lead to application crashes or system instability when the assembler encounters improperly formatted pragma directives during code compilation.
The technical root cause of this vulnerability stems from inadequate input validation and error handling within the pragma processing subsystem of NASM. When the "%pragma limit" directive is improperly constructed or contains malformed parameters, the functions process_pragma, search_pragma_list, and nasm_set_limit fail to properly check for NULL pointer references before attempting to dereference them. This behavior aligns with CWE-476 which identifies NULL pointer dereference as a common weakness in software security. The flaw occurs during the parsing and execution of assembly pragma directives, which are used to control various aspects of the assembly process including memory limits and other compiler behaviors.
The operational impact of this vulnerability extends beyond simple application crashes, as it can be exploited to cause denial of service conditions in environments where NASM is used for automated assembly processing. Attackers could craft malicious assembly files containing malformed pragma directives to trigger the NULL pointer dereference, leading to system instability or complete application termination. This vulnerability is particularly concerning in build automation systems, continuous integration pipelines, or any environment where NASM processes untrusted assembly code. The flaw can be leveraged by adversaries to disrupt legitimate assembly operations, potentially causing cascading failures in software development workflows or deployment processes that rely on NASM for code compilation.
Mitigation strategies for this vulnerability should prioritize immediate patching of NASM to version 2.15.02 or later, which contains the necessary fixes for the NULL pointer dereference issues. System administrators should implement input validation measures to prevent processing of untrusted assembly files, particularly those containing pragma directives. Additionally, organizations should consider implementing sandboxing mechanisms when processing assembly code, as recommended by ATT&CK technique T1059.006 for executing malicious code through legitimate system tools. Regular security assessments of assembly toolchains and proper access controls should be enforced to minimize the attack surface. The vulnerability demonstrates the importance of robust error handling in compiler toolchains and highlights the need for comprehensive input validation in all components of software development environments.