CVE-2018-8883 in Netwide Assembler
Summary
by MITRE
Netwide Assembler (NASM) 2.13.02rc2 has a buffer over-read in the parse_line function in asm/parser.c via uncontrolled access to nasm_reg_flags.
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Analysis
by VulDB Data Team • 01/15/2020
The vulnerability identified as CVE-2018-8883 affects Netwide Assembler version 2.13.02rc2 and represents a critical buffer over-read condition within the assembly parsing functionality. This issue occurs in the parse_line function located in the asm/parser.c source file, where the software fails to properly validate input data before processing register flag information. The flaw manifests when the nasm_reg_flags variable is accessed without adequate bounds checking, creating a scenario where maliciously crafted assembly code could trigger unauthorized memory access patterns.
The technical implementation of this vulnerability stems from inadequate input validation mechanisms within the parser component of NASM. When the parser encounters specific assembly instructions containing malformed register flag references, it attempts to read beyond the allocated memory boundaries of the nasm_reg_flags array. This over-read condition allows an attacker to access memory locations that should remain protected, potentially exposing sensitive data or enabling further exploitation techniques. The vulnerability operates at the level of assembly language parsing where register information is processed during code compilation, making it particularly dangerous for developers working with low-level code generation.
From an operational impact perspective, this vulnerability presents significant risks to software development environments that rely on NASM for assembling code. Attackers could potentially exploit this weakness to gain unauthorized access to memory contents, leading to information disclosure or system compromise. The buffer over-read condition could be leveraged to extract confidential data from memory, potentially including cryptographic keys, passwords, or other sensitive information stored in adjacent memory locations. Additionally, this vulnerability may enable more sophisticated attacks such as code execution or denial of service conditions that could disrupt legitimate development workflows.
Security practitioners should consider this vulnerability in the context of CWE-125 which specifically addresses out-of-bounds read conditions, and its relationship to ATT&CK technique T1059.1002 which covers the use of command-line interfaces for malicious code execution. The vulnerability aligns with ATT&CK's software supply chain compromise patterns since it affects a widely used development tool. Organizations utilizing NASM for assembly code generation should implement immediate mitigations including updating to patched versions of the software, implementing input validation controls, and monitoring for anomalous memory access patterns. The recommended remediation involves applying the official patches released by the NASM development team, which address the buffer over-read condition by implementing proper bounds checking for the nasm_reg_flags variable and ensuring all memory accesses remain within allocated boundaries.