The Qualys Cloud Agent included a bundled uninstall script (qagent_uninstall.sh), specific to MacOS and Linux supported versions that invoked multiple system commands without using absolute paths and without sanitizing the $PATH environment. If the uninstall script is executed with elevated privileges (e.g., via sudo) in an environment where $PATH has been manipulated, an attacker with root/sudo privileges could cause malicious executables to be run in place of the intended system binaries. This behavior can be leveraged for local privilege escalation and arbitrary command execution under elevated privileges.
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