Run the following script to disable the cramfs module: -IF- the module is available in the running kernel: - Create a file ending inconf with install cramfs /bin/false in the /etc/modprobe.d/ directory - Create a file ending inconf with blacklist cramfs in the /etc/modprobe.d/ directory - Unload cramfs from the kernel -IF- available in ANY installed kernel: - Create a file ending inconf with blacklist cramfs in the /etc/modprobe.d/ directory -IF- the kernel module is not available on the system or pre-compiled into the kernel: - No remediation is necessary #!/usr/bin/env bash { l_mname="cramfs" # set module name l_mtype="fs" # set module type l_mpath="/lib/modules/**/kernel/$l_mtype" l_mpname="$(tr '-' '_' <<< "$l_mname")" l_mndir="$(tr '-' '/' <<< "$l_mname")" module_loadable_fix() { # If the module is currently loadable, add "install {MODULE_NAME} /bin/false" to a file in "/etc/modprobe.d" l_loadable="$(modprobe -n -v "$l_mname")" [ "$(wc -l <<< "$l_loadable")" -gt "1" ] && l_loadable="$(grep -P -- "(^h*install|b$l_mname)b" <<< "$l_loadable")" if ! grep -Pq -- '^h*install /bin/(true|false)' <<< "$l_loadable"; then echo -e " - setting module: \"$l_mname\" to be not loadable" echo -e "install $l_mname /bin/false" >> /etc/modprobe.d/"$l_mpname".conf fi } module_loaded_fix() { # If the module is currently loaded, unload the module if lsmod | grep "$l_mname" > /dev/null 2>&1; then echo -e " - unloading module \"$l_mname\"" modprobe -r "$l_mname" fi } module_deny_fix() { # If the module isn't deny listed, denylist the module if ! modprobe --showconfig | grep -Pq -- "^h*blacklisth+$l_mpnameb"; then echo -e " - deny listing \"$l_mname\"" echo -e "blacklist $l_mname" >> /etc/modprobe.d/"$l_mpname".conf fi } # Check if the module exists on the system for l_mdir in $l_mpath; do if [ -d "$l_mdir/$l_mndir" ] && [ -n "$(ls -A $l_mdir/$l_mndir)" ]; then echo -e " - module: \"$l_mname\" exists in \"$l_mdir\" - checking if disabled..." module_deny_fix if [ "$l_mdir" = "/lib/modules/$(uname -r)/kernel/$l_mtype" ]; then module_loadable_fix module_loaded_fix fi else echo -e " - module: \"$l_mname\" doesn't exist in \"$l_mdir\" " fi done echo -e " - remediation of module: \"$l_mname\" complete " }

Name	Audit Name	Plugin	Category
1.1.1.1 Ensure cramfs kernel module is not available	CIS CentOS Linux 7 v4.0.0 L1 Workstation	Unix	CONFIGURATION MANAGEMENT
1.1.1.1 Ensure cramfs kernel module is not available	CIS CentOS Linux 7 v4.0.0 L1 Server	Unix	CONFIGURATION MANAGEMENT

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