CVE-2008-4474 in freeradius
Summary
by MITRE
freeradius-dialupadmin in freeradius 2.0.4 allows local users to overwrite arbitrary files via a symlink attack on temporary files in (1) backup_radacct, (2) clean_radacct, (3) monthly_tot_stats, (4) tot_stats, and (5) truncate_radacct.
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Analysis
by VulDB Data Team • 08/18/2019
The vulnerability identified as CVE-2008-4474 represents a critical local privilege escalation issue within the freeradius-dialupadmin component of freeradius version 2.0.4. This flaw stems from insecure temporary file handling practices that enable local attackers to manipulate system files through symbolic link attacks. The vulnerability affects multiple administrative scripts including backup_radacct, clean_radacct, monthly_tot_stats, tot_stats, and truncate_radacct, all of which create temporary files without proper security controls. The underlying technical flaw resides in the improper use of temporary file creation methods that do not adequately verify file ownership or existence before writing data to these locations. This insecure practice directly maps to CWE-377, which addresses the creation of temporary files with insecure permissions and the improper handling of symbolic links during file operations. Attackers can exploit this vulnerability by creating malicious symbolic links in the directories where these scripts expect to find temporary files, thereby allowing them to overwrite arbitrary files on the system with the privileges of the user running the administrative scripts.
The operational impact of this vulnerability extends beyond simple file overwriting capabilities, as it provides attackers with potential paths to escalate privileges and compromise system integrity. When these administrative scripts execute with elevated privileges, the symlink attack can result in arbitrary code execution or privilege escalation to root level access. The vulnerability is particularly concerning because it affects system administration tools that typically run with higher privileges than regular user applications, creating a significant attack surface for local users who may not have direct access to system resources. The attack vector is straightforward yet effective, requiring only that an attacker gain access to a system where these scripts are executed and can manipulate the temporary file creation process. This aligns with ATT&CK technique T1059.007 for execution through scripts, where local privilege escalation techniques leverage insecure file handling practices to achieve unauthorized system access.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security hardening measures. The most effective immediate solution involves patching the freeradius package to version 2.0.5 or later, where the insecure temporary file creation methods have been corrected. System administrators should also implement proper file permissions and ownership controls on the affected scripts and their temporary file directories. The recommended approach includes using secure temporary file creation methods such as mkstemp() or similar functions that guarantee file uniqueness and prevent symbolic link attacks. Additionally, implementing proper input validation and ensuring that administrative scripts run with the minimum necessary privileges can significantly reduce the impact of such vulnerabilities. Organizations should also consider implementing monitoring and alerting mechanisms to detect suspicious file creation patterns in system administration directories. The vulnerability serves as a prime example of why secure coding practices must be enforced throughout the software development lifecycle, particularly when dealing with temporary file operations that could be exploited by local attackers to gain unauthorized system access.