CVE-2008-5154 in p3nfs
Summary
by MITRE
bluetooth.rc in p3nfs 5.19 allows local users to overwrite arbitrary files via a symlink attack on the /tmp/blue.log temporary file.
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Analysis
by VulDB Data Team • 10/14/2018
The vulnerability identified as CVE-2008-5154 affects the p3nfs 5.19 implementation and specifically targets the bluetooth.rc script which handles bluetooth service operations. This issue represents a classic symlink attack scenario where local users can exploit insecure temporary file handling to gain unauthorized file system access. The vulnerability stems from the script's improper handling of the /tmp/blue.log temporary file, which creates a predictable path that can be manipulated by attackers. The flaw allows malicious users to overwrite arbitrary files on the system by creating symbolic links that redirect the script's write operations to locations of their choosing. This type of vulnerability falls under the category of insecure temporary file creation as defined by CWE-377, where the use of predictable temporary file names creates opportunities for privilege escalation attacks. The attack vector is particularly concerning because it operates at the local user level, meaning any user with access to the system can potentially exploit this weakness to overwrite critical system files or configuration data.
The technical implementation of this vulnerability exploits the predictable nature of the /tmp/blue.log file path and the lack of proper atomic file creation mechanisms within the bluetooth.rc script. When the script executes and attempts to write to the temporary file, it does not validate whether the target path is a symbolic link or if the file already exists with inappropriate permissions. This insecure pattern allows attackers to establish symbolic links in the /tmp directory before the script runs, causing the script to write data to locations controlled by the attacker rather than the intended temporary file location. The operational impact extends beyond simple file overwrites as this vulnerability can be leveraged to modify system configuration files, replace critical executables, or manipulate log data to hide malicious activities. The attack requires local system access but does not need elevated privileges, making it particularly dangerous in multi-user environments where users may have varying levels of access. This vulnerability aligns with ATT&CK technique T1059.007 for executing commands through script interpreters and T1548.001 for privilege escalation through abuse of system permissions.
The mitigation strategies for CVE-2008-5154 should focus on implementing secure temporary file creation practices and eliminating predictable file paths in the bluetooth.rc script. System administrators should ensure that temporary files are created with proper permissions and atomic operations that prevent symbolic link attacks. The recommended approach involves using secure file creation functions that verify file ownership and permissions before writing, or implementing directory-specific temporary file handling that avoids the use of predictable /tmp locations. Additionally, the script should be updated to validate the integrity of temporary file paths and reject any operations that would result in symbolic link resolution. Security patches should enforce proper file creation atomicity and eliminate the possibility of attackers manipulating the temporary file location before the script executes. Organizations should also implement regular security audits to identify similar insecure temporary file patterns in other system components and apply the principle of least privilege to limit the impact of such vulnerabilities. The remediation process should include verifying that the fixed script properly handles file operations and that no other similar vulnerabilities exist in related components.