Nagios XI versions prior to 2024R2 contain an improperly owned script, process_perfdata.pl, which is executed periodically as the nagios user but owned by www-data. Because the file was writable by www-data, an attacker with web server privileges could modify its contents, leading to arbitrary code execution as the nagios user when the script is next run. This improper ownership and permission configuration enables local privilege escalation.
Weakness
The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.
Potential Mitigations
- Run the code in a “jail” or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which files can be accessed in a particular directory or which commands can be executed by the software.
- OS-level examples include the Unix chroot jail, AppArmor, and SELinux. In general, managed code may provide some protection. For example, java.io.FilePermission in the Java SecurityManager allows the software to specify restrictions on file operations.
- This may not be a feasible solution, and it only limits the impact to the operating system; the rest of the application may still be subject to compromise.
- Be careful to avoid CWE-243 and other weaknesses related to jails.
References