CVE-2001-1301 in Emacs
Summary
by MITRE
rcs2log, as used in Emacs 20.4, xemacs 21.1.10 and other versions before 21.4, and possibly other packages, allows local users to modify files of other users via a symlink attack on a temporary file.
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Analysis
by VulDB Data Team • 06/13/2024
The vulnerability identified as CVE-2001-1301 represents a classic file system security flaw affecting version control and text editing software ecosystems. This issue specifically impacts rcs2log utilities within Emacs and XEmacs environments, where the software fails to properly handle temporary file creation mechanisms during version control operations. The flaw stems from inadequate validation of temporary file paths, creating opportunities for malicious users to exploit symbolic link attacks against system resources.
The technical implementation of this vulnerability resides in the improper handling of temporary file creation processes within the rcs2log utility. When processing revision control logs, the utility creates temporary files without sufficient security checks to ensure these files are created in secure locations. Attackers can exploit this by creating symbolic links in predictable locations that the utility will subsequently overwrite, effectively redirecting file operations to target files owned by other users. This attack vector operates under the broader category of temporary file handling vulnerabilities classified as CWE-352, which encompasses Cross-Site Request Forgery and related privilege escalation techniques.
The operational impact of CVE-2001-1301 extends beyond simple file modification, as it enables unauthorized access to sensitive user data and system resources. Local attackers with minimal privileges can leverage this vulnerability to read, modify, or even delete files belonging to other users within the same system environment. The attack is particularly concerning because it requires no network access and can be executed from within the local system, making it difficult to detect through traditional network monitoring approaches. This vulnerability aligns with ATT&CK technique T1059.001 for executing malicious code through local system processes and T1548.001 for privilege escalation through local system modifications.
The exploitation of this vulnerability demonstrates how seemingly benign utility functions can become security risks when proper file system security controls are not implemented. The affected versions of Emacs and XEmacs were widely used in development environments, making this vulnerability particularly dangerous in organizational settings where multiple users share system resources. The attack requires the attacker to have local access and knowledge of the system's file structure, but once executed, can result in significant data compromise and system integrity violations. This flaw highlights the importance of secure temporary file handling practices as outlined in various security frameworks including the Open Web Application Security Project (OWASP) guidelines for secure file operations and the Common Weakness Enumeration standards for temporary file security.
Mitigation strategies for CVE-2001-1301 primarily involve updating affected software to versions that properly implement secure temporary file creation mechanisms. System administrators should immediately upgrade to Emacs 21.4 or later versions and XEmacs 21.4 or newer releases where the vulnerability has been addressed through proper file descriptor handling and temporary file location validation. Additionally, organizations should implement regular security audits of their software environments to identify and remediate similar vulnerabilities in other applications. The fix typically involves ensuring that temporary files are created with proper permissions and are located in secure directories that cannot be manipulated through symbolic link attacks. System hardening measures including restricting write access to temporary directories and implementing proper file system permissions can further reduce the attack surface for this class of vulnerabilities.