#!/bin/bash # # CIS Debian Hardening # # # 6.1.14 Audit SGID executables (Not Scored) # set -e # One error, it's over set -u # One variable unset, it's over # shellcheck disable=2034 HARDENING_LEVEL=2 DESCRIPTION="Find SGID system executables." IGNORED_PATH='' # This function will be called if the script status is on enabled / audit mode audit () { info "Checking if there are sgid files" FS_NAMES=$(df --local -P | awk '{ if (NR!=1) print $6 }' ) # shellcheck disable=2086 if [ ! -z $IGNORED_PATH ]; then FOUND_BINARIES=$( $SUDO_CMD find $FS_NAMES -xdev -type f -perm -2000 -regextype 'egrep' ! -regex "$IGNORED_PATH" -print) else FOUND_BINARIES=$( $SUDO_CMD find $FS_NAMES -xdev -type f -perm -2000 -print) fi BAD_BINARIES="" for BINARY in $FOUND_BINARIES; do if grep -qw "$BINARY" <<< "$EXCEPTIONS"; then debug "$BINARY is confirmed as an exception" else BAD_BINARIES="$BAD_BINARIES $BINARY" fi done if [ ! -z "$BAD_BINARIES" ]; then crit "Some sgid files are present" FORMATTED_RESULT=$(sed "s/ /\n/g" <<< "$BAD_BINARIES" | sort | uniq | tr '\n' ' ') crit "$FORMATTED_RESULT" else ok "No unknown sgid files found" fi } # This function will be called if the script status is on enabled mode apply () { info "Removing sgid on valid binary may seriously harm your system, report only here" } # This function will create the config file for this check with default values create_config() { cat <<EOF status=audit # Put here valid binaries with sgid enabled separated by spaces EXCEPTIONS="/sbin/unix_chkpwd /usr/sbin/unix_chkpwd /usr/bin/bsd-write /usr/bin/chage /usr/bin/crontab /usr/bin/expiry /usr/bin/mutt_dotlock /usr/bin/screen /usr/bin/ssh-agent /usr/bin/wall /usr/sbin/postdrop /usr/sbin/postqueue /usr/bin/at /usr/bin/dotlockfile /usr/bin/mail-lock /usr/bin/mail-touchlock /usr/bin/mail-unlock" EOF } # This function will check config parameters required check_config() { if [ -z "$EXCEPTIONS" ]; then EXCEPTIONS="@" fi } # Source Root Dir Parameter if [ -r /etc/default/cis-hardening ]; then . /etc/default/cis-hardening fi if [ -z "$CIS_ROOT_DIR" ]; then echo "There is no /etc/default/cis-hardening file nor cis-hardening directory in current environment." echo "Cannot source CIS_ROOT_DIR variable, aborting." exit 128 fi # Main function, will call the proper functions given the configuration (audit, enabled, disabled) if [ -r "$CIS_ROOT_DIR"/lib/main.sh ]; then # shellcheck source=/opt/debian-cis/lib/main.sh . "$CIS_ROOT_DIR"/lib/main.sh else echo "Cannot find main.sh, have you correctly defined your root directory? Current value is $CIS_ROOT_DIR in /etc/default/cis-hardening" exit 128 fi