Run the following script to update permissions and ownership on files in /var/log Although the script is not destructive, ensure that the output of the audit procedure is captured in the event that the remediation causes issues. #!/usr/bin/env bash { a_output2=() f_file_test_fix() { a_out2=() maxperm="$( printf '%o' $(( 0777 & ~$perm_mask)) )" if [ $(( $l_mode & $perm_mask )) -gt 0 ]; then a_out2+=(" o Mode: \"$l_mode\" should be \"$maxperm\" or more restrictive" " x Removing excess permissions") chmod "$l_rperms" "$l_fname" fi if [[ ! "$l_user" =~ $l_auser ]]; then a_out2+=(" o Owned by: \"$l_user\" and should be owned by \"${l_auser//|/ or }\"" " x Changing ownership to: \"$l_fix_account\"") chown "$l_fix_account" "$l_fname" fi if [[ ! "$l_group" =~ $l_agroup ]]; then a_out2+=(" o Group owned by: \"$l_group\" and should be group owned by \"${l_agroup//|/ or }\"" " x Changing group ownership to: \"$l_fix_account\"") chgrp "$l_fix_account" "$l_fname" fi [ "${#a_out2[@]}" -gt 0 ] && a_output2+=(" - File: \"$l_fname\" is:" "${a_out2[@]}") } l_fix_account='root' while IFS= read -r -d $'0' l_file; do while IFS=: read -r l_fname l_mode l_user l_group; do if grep -Pq -- '/(apt)h*$' <<< "$(dirname "$l_fname")"; then perm_mask='0133' l_rperms="u-x,go-wx" l_auser="root" l_agroup="(root|adm)"; f_file_test_fix else case "$(basename "$l_fname")" in lastlog | lastlog.* | wtmp | wtmp.* | wtmp-* | btmp | btmp.* | btmp-* | README) perm_mask='0113' l_rperms="ug-x,o-wx" l_auser="root" l_agroup="(root|utmp)" f_file_test_fix ;; cloud-init.log* | localmessages* | waagent.log*) perm_mask='0133' l_rperms="u-x,go-wx" l_auser="(root|syslog)" l_agroup="(root|adm)" file_test_fix ;; secure | auth.log | syslog | messages) perm_mask='0137' l_rperms="u-x,g-wx,o-rwx" l_auser="(root|syslog)" l_agroup="(root|adm)" f_file_test_fix ;; SSSD | sssd) perm_mask='0117' l_rperms="ug-x,o-rwx" l_auser="(root|SSSD)" l_agroup="(root|SSSD)" f_file_test_fix ;; gdm | gdm3) perm_mask='0117' l_rperms="ug-x,o-rwx" l_auser="root" l_agroup="(root|gdm|gdm3)" f_file_test_fix ;; *.journal | *.journal~) perm_mask='0137' l_rperms="u-x,g-wx,o-rwx" l_auser="root" l_agroup="(root|systemd-journal)" f_file_test_fix ;; *) perm_mask='0137' l_rperms="u-x,g-wx,o-rwx" l_auser="(root|syslog)" l_agroup="(root|adm)" if [ "$l_user" = "root" ] || ! grep -Pq -- "^h*$(awk -F: '$1=="'"$l_user"'" {print $7}' /etc/passwd)b" /etc/shells; then ! grep -Pq -- "$l_auser" <<< "$l_user" && l_auser="(root|syslog|$l_user)" ! grep -Pq -- "$l_agroup" <<< "$l_group" && l_agroup="(root|adm|$l_group)" fi f_file_test_fix ;; esac fi done < <(stat -Lc '%n:%#a:%U:%G' "$l_file") done < <(find -L /var/log -type f ( -perm /0137 -o ! -user root -o ! -group root ) -print0) if [ "${#a_output2[@]}" -le 0 ]; then # If all files passed, then we report no changes a_output+=(" - All files in \"/var/log/\" have appropriate permissions and ownership") printf ' %s' "- All files in \"/var/log/\" have appropriate permissions and ownership" " o No changes required" "" else printf ' %s' "${a_output2[@]}" "" fi } Note: You may also need to change the configuration for your logging software or services for any logs that had incorrect permissions. If there are services that log to other locations, ensure that those log files have the appropriate permissions.

Name	Audit Name	Plugin	Category
6.1.4.1 Ensure access to all logfiles has been configured	CIS Debian Linux 12 v1.1.0 L1 Server	Unix	ACCESS CONTROL, MEDIA PROTECTION
6.1.4.1 Ensure access to all logfiles has been configured	CIS Debian Linux 12 v1.1.0 L1 Workstation	Unix	ACCESS CONTROL, MEDIA PROTECTION

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