The audit system must be configured to audit the loading and unloading of dynamic kernel modules.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-38580	RHEL-06-000202	SV-50381r2_rule		Medium

Description
The addition/removal of kernel modules can be used to alter the behavior of the kernel and potentially introduce malicious code into kernel space. It is important to have an audit trail of modules that have been introduced into the kernel.

STIG	Date
Red Hat Enterprise Linux 6 Security Technical Implementation Guide	2018-03-01

Details

Check Text ( C-46138r3_chk )
To determine if the system is configured to audit execution of module management programs, run the following commands: $ sudo egrep -e "(-w \|-F path=)/sbin/insmod" /etc/audit/audit.rules $ sudo egrep -e "(-w \|-F path=)/sbin/rmmod" /etc/audit/audit.rules $ sudo egrep -e "(-w \|-F path=)/sbin/modprobe" /etc/audit/audit.rules If the system is configured to audit this activity, it will return a line. To determine if the system is configured to audit calls to the "init_module" system call, run the following command: $ sudo grep -w "init_module" /etc/audit/audit.rules If the system is configured to audit this activity, it will return a line. To determine if the system is configured to audit calls to the "delete_module" system call, run the following command: $ sudo grep -w "delete_module" /etc/audit/audit.rules If the system is configured to audit this activity, it will return a line. If no line is returned for any of these commands, this is a finding.

Check Text ( C-46138r3_chk )

To determine if the system is configured to audit execution of module management programs, run the following commands:

$ sudo egrep -e "(-w |-F path=)/sbin/insmod" /etc/audit/audit.rules
$ sudo egrep -e "(-w |-F path=)/sbin/rmmod" /etc/audit/audit.rules
$ sudo egrep -e "(-w |-F path=)/sbin/modprobe" /etc/audit/audit.rules

If the system is configured to audit this activity, it will return a line.

To determine if the system is configured to audit calls to the "init_module" system call, run the following command:

$ sudo grep -w "init_module" /etc/audit/audit.rules

If the system is configured to audit this activity, it will return a line.

To determine if the system is configured to audit calls to the "delete_module" system call, run the following command:

$ sudo grep -w "delete_module" /etc/audit/audit.rules

If the system is configured to audit this activity, it will return a line.

If no line is returned for any of these commands, this is a finding.

Fix Text (F-43528r2_fix)
Add the following to "/etc/audit/audit.rules" in order to capture kernel module loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system: -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=[ARCH] -S init_module -S delete_module -k modules