CVE-1999-1439 in gcc
Summary
by MITRE
gcc 2.7.2 allows local users to overwrite arbitrary files via a symlink attack on temporary .i, .s, or .o files.
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Analysis
by VulDB Data Team • 04/17/2026
The vulnerability described in CVE-1999-1439 represents a significant security flaw in the GNU Compiler Collection version 2.7.2 that enables local users to perform file overwriting attacks through symbolic link manipulation. This issue specifically targets the temporary file handling mechanisms used during the compilation process, creating a privilege escalation vector that can be exploited by malicious users with access to the system. The vulnerability stems from the compiler's failure to properly validate or secure temporary files created during compilation operations, particularly those with extensions .i, .s, or .o which represent preprocessed source files, assembly files, and object files respectively.
The technical flaw manifests when gcc creates temporary files in predictable locations without adequate security measures to prevent symbolic link attacks. During compilation, the compiler generates these temporary files to store intermediate results before proceeding to the next stage of the compilation process. When a local user can manipulate the environment to create symbolic links with the same names as these temporary files, they can redirect the compiler's output to overwrite arbitrary files on the system. This attack vector operates under the principle of time-of-check to time-of-use vulnerabilities where the system checks for file existence at one point but writes to a different location at another point.
The operational impact of this vulnerability extends beyond simple file overwriting, as it can be leveraged to compromise system integrity and potentially escalate privileges. An attacker could exploit this weakness to overwrite critical system files, configuration files, or even files owned by other users with elevated permissions. The vulnerability affects any local user who can influence the compilation environment, making it particularly dangerous in multi-user systems or shared development environments where users might not have appropriate access controls. The attack requires minimal privileges and can be executed without requiring special permissions beyond basic user access to the system.
This vulnerability aligns with CWE-377 and CWE-378, which address insecure temporary file creation and inadequate temporary file permissions respectively. The issue also maps to ATT&CK technique T1059.007 for execution through scripting and T1548.001 for privilege escalation through file permissions. The flaw demonstrates the importance of proper temporary file handling in security-critical applications and highlights how seemingly benign compilation processes can become attack vectors when proper security controls are not implemented. Organizations should ensure that all temporary file operations use secure methods such as creating files with unique names, setting appropriate permissions, and avoiding predictable file paths.
Mitigation strategies for CVE-1999-1439 involve updating to newer versions of gcc where this vulnerability has been addressed through improved temporary file handling mechanisms. System administrators should implement proper file permission controls and ensure that temporary directories have restrictive permissions to prevent symbolic link creation. The use of secure temporary file creation functions and the implementation of proper sandboxing mechanisms during compilation can prevent exploitation. Additionally, monitoring for unusual file access patterns and implementing least privilege principles can help detect and prevent potential exploitation attempts. Regular security audits of compilation environments and proper system hardening practices should be implemented to prevent similar vulnerabilities from arising in other software components.
The vulnerability serves as a historical example of how insecure temporary file handling can create persistent security risks in widely used software tools. Modern compiler implementations have addressed these issues through better security practices including the use of secure temporary file creation functions, proper file permission management, and elimination of predictable file paths. Organizations should maintain updated software versions and implement comprehensive security measures to prevent exploitation of similar vulnerabilities in current systems. This case underscores the critical importance of security considerations in development tools, as they form the foundation of software development environments and can become attack vectors if not properly secured against common exploitation techniques.