4.1.18 Ensure kernel module loading and unloading is collected - init_module

Information

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".

Rationale:

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 Edit or create a file in the /etc/audit/rules.d/ directory ending in
.rules
Example: vi /etc/audit/rules.d/audit.rules
and add the following lines:

-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 Edit or create a file in the /etc/audit/rules.d/ directory ending in
.rules
Example: vi /etc/audit/rules.d/audit.rules
and add the following lines:

-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

Notes:

Reloading the auditd config to set active settings may require a system reboot.

See Also

https://workbench.cisecurity.org/files/2420

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6, CSCv6|3, CSCv7|5.1

Plugin: Unix

Control ID: d55e427b2fa1d654ab6afc8e9ad6ae077ea4c02abcb97b3a03c4cfb3fb7b291f