CVE-2005-1194 in NASM
Summary
by MITRE
Stack-based buffer overflow in the ieee_putascii function for nasm 0.98 and earlier allows attackers to execute arbitrary code via a crafted asm file, a different vulnerability than CVE-2004-1287.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 07/03/2019
The vulnerability identified as CVE-2005-1194 represents a critical stack-based buffer overflow affecting the netwide assembler nasm version 0.98 and earlier. This flaw resides within the ieee_putascii function, which processes ASCII data during assembly operations. The vulnerability stems from inadequate input validation and bounds checking when handling crafted assembly files that contain maliciously formatted data. Attackers can exploit this weakness by preparing a specially crafted assembly file that triggers the buffer overflow during the processing of IEEE floating-point number representations. The flaw specifically manifests when the assembler encounters malformed ASCII data that exceeds the allocated stack buffer space, allowing malicious code execution through stack corruption.
The technical implementation of this vulnerability follows the classic stack-based buffer overflow pattern where insufficient bounds checking permits data to overwrite adjacent stack memory locations. When nasm processes the ieee_putascii function with malicious input, the function fails to validate the length of incoming ASCII data before copying it to a fixed-size stack buffer. This allows an attacker to overwrite return addresses, saved registers, and other critical stack contents. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, which directly enables arbitrary code execution through controlled memory corruption. The attack vector requires the victim to process a specially crafted assembly file, making it a code execution vulnerability that can be delivered through various means including social engineering or automated processing systems.
The operational impact of CVE-2005-1194 extends beyond simple code execution to potentially compromise entire development environments and build systems. Since nasm is a widely used assembler in software development, exploitation could lead to unauthorized code injection in legitimate software builds, creating backdoors or malware distribution channels. The vulnerability affects systems where nasm is used for assembly processing, particularly in environments where untrusted assembly files are processed automatically. This makes it especially dangerous in continuous integration systems, automated build environments, or any scenario where assembly files from external sources are assembled without proper sanitization. The attack can result in complete system compromise when successful, as the overflow allows attackers to redirect program execution flow to malicious code.
Mitigation strategies for CVE-2005-1194 require immediate action to upgrade to nasm version 0.99 or later, which contains the necessary patches to address the buffer overflow. Organizations should implement strict input validation procedures for all assembly files processed by nasm, including automated scanning for potentially malicious patterns. The implementation of stack protection mechanisms such as stack canaries and address space layout randomization can provide additional defense-in-depth layers. Security teams should also establish secure coding practices for assembly file handling and consider using sandboxing techniques when processing untrusted assembly code. Regular security audits of development environments and build systems are essential to identify and remediate similar vulnerabilities. The ATT&CK framework categorizes this vulnerability under T1059.006 for execution through assembly languages, highlighting the need for comprehensive protection of development toolchains and build processes against such threats.