CVE-2001-1333 in CUPS
Summary
by MITRE
Linux CUPS before 1.1.6 does not securely handle temporary files, possibly due to a symlink vulnerability that could allow local users to overwrite files.
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Analysis
by VulDB Data Team • 05/30/2018
The vulnerability identified as CVE-2001-1333 affects the Common Unix Printing System (CUPS) version 1.1.5 and earlier, representing a critical security flaw in the print spooling subsystem of Linux operating systems. This issue stems from improper handling of temporary files within the CUPS framework, creating a pathway for local privilege escalation attacks. The vulnerability specifically manifests when CUPS creates temporary files during print job processing, failing to properly validate or secure these temporary file operations. The flaw allows malicious local users to exploit symbolic link attacks by manipulating the temporary file creation process, potentially enabling them to overwrite arbitrary files on the system with elevated privileges. This represents a classic example of a temporary file race condition vulnerability where the timing and permissions of file creation can be manipulated by unauthorized users.
The technical implementation of this vulnerability involves the CUPS printing daemon creating temporary files in predictable locations without proper security controls or atomic file creation mechanisms. When print jobs are processed, CUPS generates temporary files that are subsequently used in the printing pipeline, but these files are created with insufficient permissions or in directories that can be manipulated by local users. Attackers can exploit this by creating symbolic links in the temporary file path that point to sensitive system files, such as configuration files or binaries, and then triggering the print job processing which causes CUPS to write data to the targeted files through the symbolic link. This attack vector directly maps to CWE-377, which addresses insecure temporary file handling, and CWE-378, which covers the creation of temporary files with insecure permissions. The vulnerability demonstrates poor security practices in file system operations and highlights the importance of proper privilege separation and secure temporary file management in system services.
The operational impact of CVE-2001-1333 extends beyond simple file overwriting capabilities, as it enables local users to potentially escalate their privileges to root level access. When combined with other local exploitation techniques, this vulnerability can allow attackers to modify critical system files, replace binaries with malicious versions, or alter configuration files that control system behavior. The attack requires local access to the system but can result in complete system compromise, as the compromised CUPS service typically runs with elevated privileges. This vulnerability is particularly dangerous in multi-user environments where less privileged users might gain access to systems through various attack vectors and then leverage this weakness to escalate their privileges. The attack can be executed without requiring network access or specialized tools beyond standard local user privileges, making it a particularly attractive target for attackers seeking persistent access to systems. This vulnerability also aligns with ATT&CK technique T1068, which covers local privilege escalation through the exploitation of system vulnerabilities, and T1548.001, which addresses privilege escalation through the exploitation of system services.
Mitigation strategies for CVE-2001-1333 require immediate patching of affected systems with CUPS version 1.1.6 or later, which implements proper temporary file handling mechanisms and secure file creation practices. System administrators should ensure that all CUPS installations are updated to the patched versions and that proper file permissions are enforced for temporary directories. Additional protective measures include implementing proper access controls on the CUPS configuration and temporary file directories, monitoring for unauthorized file modifications, and conducting regular security audits of print services. The vulnerability also underscores the importance of following secure coding practices such as using atomic file creation methods, implementing proper file permission controls, and avoiding predictable temporary file names. Organizations should also consider implementing intrusion detection systems to monitor for suspicious file access patterns and ensure that print services are properly isolated from other system components. Regular security assessments and vulnerability scanning should include checks for outdated CUPS installations to prevent exploitation of this and similar legacy vulnerabilities.