Details

Monitor the loading and unloading of kernel modules. The programs insmod (install a kernel module), rmmod (remove a kernel module), and modprobe (a more sophisticated program to load and unload modules, as well as some other features) control loading and unloading of modules. The init_module (load a module) and delete_module (delete a module) system calls control loading and unloading of modules. Any execution of the loading and unloading module programs and system calls will trigger an audit record with an identifier of ‘modules’. Monitoring the use of insmod, rmmod and modprobe could provide system administrators with evidence that an unauthorized user loaded or unloaded a kernel module, possibly compromising the security of the system. Monitoring of the init_module and delete_module system calls would reflect an unauthorized user attempting to use a different program to load and unload modules.

Solution

For 32 bit systems add the following lines to the /etc/audit/audit.rules file:
-w /sbin/insmod -p x -k modules
-w /sbin/rmmod -p x -k modules
-w /sbin/modprobe -p x -k modules
-a always,exit -F arch=b32 -S init_module -S delete_module -k modules

For 64 bit systems add the following lines to the /etc/audit/audit.rules file:
-w /sbin/insmod -p x -k modules
-w /sbin/rmmod -p x -k modules
-w /sbin/modprobe -p x -k modules
-a always,exit -F arch=b64 -S init_module -S delete_module -k modules

Supportive Information

The following resource is also helpful.

• https://www.cisco.com/c/en/us/td/docs/security/firepower/623/configuration/guide/fpmc-config-guide-v623.html

This security hardening control applies to the following category of controls within NIST 800-53: Audit and Accountability.This control applies to the following type of system Unix.

References

• 800-53|AU-12
• CSCv6|3

Source

• Tenable.com/audits