CVE-2008-5142 in freebsd-sendpr
Summary
by MITRE
sendbug in freebsd-sendpr 3.113+5.3 on Debian GNU/Linux allows local users to overwrite arbitrary files via a symlink attack on a /tmp/pr.##### temporary file.
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Analysis
by VulDB Data Team • 12/04/2017
The vulnerability identified as CVE-2008-5142 resides within the FreeBSD sendpr utility version 3.113+5.3 when deployed on Debian GNU/Linux systems. This issue represents a classic temporary file creation vulnerability that enables local privilege escalation through symbolic link manipulation. The flaw manifests in the sendpr utility's handling of temporary files during its operation, specifically when creating files in the /tmp directory with predictable naming patterns. The vulnerability is categorized under CWE-377 as the use of insecure temporary files and falls within the ATT&CK framework as a privilege escalation technique through local system exploitation.
The technical implementation of this vulnerability exploits the predictable naming convention of temporary files created by sendpr, which uses the pattern /tmp/pr.##### where the hash characters represent a sequence of digits. Local attackers can create symbolic links with these exact names in the /tmp directory before the sendpr utility executes, causing the utility to write data to the attacker-controlled target file instead of its intended temporary location. This symlink attack vector allows malicious users to overwrite arbitrary files with data controlled by the attacker, potentially including system configuration files, binary executables, or other sensitive data. The vulnerability is particularly concerning because it operates with the privileges of the user executing sendpr, which could be a system user or a regular user with access to the utility.
The operational impact of CVE-2008-5142 extends beyond simple file overwriting, as it can potentially enable attackers to escalate privileges or compromise system integrity. When the sendpr utility is executed with elevated privileges, such as by a system administrator or through a setuid binary, the symbolic link attack can result in privilege escalation. The vulnerability affects systems where sendpr is installed and executable, particularly those running older versions of the FreeBSD sendpr package on Debian-based distributions. The attack requires local access to the system and knowledge of the predictable temporary file naming convention, making it a local privilege escalation vulnerability rather than a remote exploit. The flaw demonstrates poor security practices in temporary file handling and highlights the importance of proper file creation security mechanisms.
Mitigation strategies for CVE-2008-5142 should focus on both immediate remediation and long-term security hardening measures. The most effective immediate fix involves updating to a patched version of the FreeBSD sendpr utility that properly handles temporary file creation using secure methods such as creating files with random names or using secure temporary file creation functions that prevent symbolic link attacks. System administrators should also implement proper file permissions and directory security measures to prevent unauthorized symlink creation in the /tmp directory. The vulnerability can be addressed through proper system patching, which aligns with NIST guidelines for vulnerability management and remediation. Additionally, implementing proper access controls and monitoring for unauthorized file system changes in temporary directories can help detect potential exploitation attempts. Organizations should consider implementing the principle of least privilege for system utilities and regularly audit installed packages to identify and remediate similar vulnerabilities in their systems.