CVE-2008-5152 in mh-book
Summary
by MITRE
inmail-show in mh-book 200605 allows local users to overwrite arbitrary files via a symlink attack on a (1) /tmp/inmail#####.log or (2) /tmp/inmail#####.stdin temporary file.
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Analysis
by VulDB Data Team • 10/14/2018
The vulnerability identified as CVE-2008-5152 resides within the inmail-show component of mh-book version 200605, presenting a significant local privilege escalation risk through symbolic link attacks. This flaw manifests when the application creates temporary files in the /tmp directory without proper security measures to prevent symlink manipulation. The vulnerability specifically affects two temporary file locations: /tmp/inmail#####.log and /tmp/inmail#####.stdin, where the ##### represents a numeric sequence that is typically generated by the application. The core issue stems from the predictable naming convention of these temporary files, combined with the lack of proper file access controls during their creation, allowing local attackers to establish symbolic links that redirect the application's write operations to arbitrary locations on the filesystem.
The technical exploitation of this vulnerability follows a well-documented pattern that aligns with CWE-377, which addresses the use of insecure temporary files in software applications. Attackers can create symbolic links with the exact same names as the temporary files that inmail-show generates, placing these links in the /tmp directory before the application executes. When the application runs and attempts to write to these temporary files, it inadvertently writes to the target file specified by the attacker's symbolic link rather than the intended temporary file location. This technique represents a classic symlink race condition attack, where the timing window between file creation and access is exploited to redirect file operations to malicious targets. The vulnerability is particularly dangerous because it can be leveraged to overwrite critical system files, configuration files, or even files owned by other users with elevated privileges.
The operational impact of CVE-2008-5152 extends beyond simple file overwriting, as it can be exploited to escalate privileges and potentially gain unauthorized access to system resources. Local users who can execute the vulnerable application can leverage this weakness to modify system-critical files, potentially leading to privilege escalation scenarios where they can gain administrative rights. The attack vector is particularly concerning because it requires minimal privileges to execute and can be automated to target specific system files or directories. This vulnerability also aligns with ATT&CK technique T1059.007, which covers the use of local commands and scripts to achieve system compromise, as attackers can use the symbolic link attack to execute malicious code through the modified target files. The implications are further amplified by the fact that this vulnerability affects a mail handling component, meaning that any local user with access to the system could potentially exploit it to modify email-related configurations or even inject malicious content into system logs.
Mitigation strategies for CVE-2008-5152 should focus on addressing the root cause through proper temporary file handling practices. The most effective approach involves implementing secure temporary file creation methods that utilize the O_EXCL flag during file creation to prevent symlink attacks, as recommended by CWE-377 guidelines. Additionally, applications should avoid creating predictable temporary filenames and instead use random or cryptographically secure identifiers that cannot be easily guessed or reproduced by attackers. System administrators should also consider implementing proper file permissions and ownership controls for the /tmp directory, ensuring that temporary files are created with restrictive permissions and that the application runs with minimal necessary privileges. The implementation of proper sandboxing techniques and the use of secure file handling libraries can further reduce the attack surface. Organizations should also conduct regular security audits of their mail handling systems and ensure that all components are updated to versions that address this specific vulnerability, as the original mh-book 200605 version is outdated and likely contains additional security weaknesses beyond this particular issue.