Nokia SR OS routers allow read-write access to the entire file system via SFTP or SCP for users configured with access console. Consequently, a low privilege authenticated user with access console can read or replace the router configuration file as well as other files stored in the Compact Flash or SD card without using CLI commands. This type of attack can lead to a compromise or denial of service of the router after the system is rebooted.
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