lynis/include/tests_firewalls

#!/bin/sh

#################################################################################
#
#   Lynis
# ------------------
#
# Copyright 2007-2015, Michael Boelen, CISOfy (michael.boelen@cisofy.com)
# Web site: https://cisofy.com
#
# Lynis comes with ABSOLUTELY NO WARRANTY. This is free software, and you are
# welcome to redistribute it under the terms of the GNU General Public License.
# See LICENSE file for usage of this software.
#
#################################################################################
#
# Firewalls
#
#################################################################################
#
    InsertSection "Software: firewalls"
#
#################################################################################
#
    IPTABLES_ACTIVE=0
    IPTABLES_INKERNEL_ACTIVE=0
    IPTABLES_MODULE_ACTIVE=0
    FIREWALL_ACTIVE=0
    FIREWALL_SOFTWARE=""
#
#################################################################################
#
    # Test        : FIRE-4511
    # Description : Check iptables kernel module
    Register --test-no FIRE-4511 --os Linux --weight L --network NO --description "Check iptables kernel module"
    if [ ${SKIPTEST} -eq 0 ]; then
        FIND=`lsmod | awk '{ print $1 }' | grep "^ip*_tables"`
        if [ ! "${FIND}" = "" ]; then
            FIREWALL_ACTIVE=1
            FIREWALL_SOFTWARE="iptables"
            IPTABLES_ACTIVE=1
            IPTABLES_MODULE_ACTIVE=1
            Display --indent 2 --text "- Checking iptables kernel module" --result FOUND --color GREEN
            logtext "Result: Found iptables in loaded kernel modules"
            for I in ${FIND}; do
                logtext "Found module: ${I}"
            done
          else
            Display --indent 2 --text "- Checking iptables kernel module" --result "NOT FOUND" --color WHITE

            # If we can't find an active module, try to find the Linux configuration file and check that
            if [ -f /proc/config.gz ]; then
                LINUXCONFIGFILE="/proc/config.gz"; tCATCMD="zcat";
            fi
            sLINUXCONFIGFILE="/boot/config-`uname -r`"
            if [ -f ${sLINUXCONFIGFILE} ]; then
                LINUXCONFIGFILE=${sLINUXCONFIGFILE}; tCATCMD="cat";
            fi

            # If we have a kernel configuration file, use it for testing
            # Do not perform test if we already found it in kernel module list, to avoid triggered it in the upcoming
            # tests, when using iptables --list
            if [ ! "${LINUXCONFIGFILE}" = "" ]; then
                if [ -f ${LINUXCONFIGFILE} -a ${IPTABLES_MODULE_ACTIVE} -eq 0 ]; then
                    logtext "Result: found kernel configuration file (${LINUXCONFIGFILE})"
                    FIND=`${tCATCMD} ${LINUXCONFIGFILE} | grep -v '^#' | grep "CONFIG_IP_NF_IPTABLES" | head -n 1`
                    if [ ! "${FIND}" = "" ]; then
                        HAVEMOD=`echo ${FIND} | cut -d '=' -f2`
                        # Do not use iptables if it's compiled as a module (=m), since we already tested for it in the
                        # active list.
                        if [ "${HAVEMOD}" = "y" ]; then
                                logtext "Result: iptables available as a module in the configuration"
                                IPTABLES_ACTIVE=1
                                IPTABLES_INKERNEL_ACTIVE=1
                                FIREWALL_ACTIVE=1
                                FIREWALL_SOFTWARE="iptables"
                                Display --indent 2 --text "- Checking iptables in config file" --result FOUND --color GREEN
                          else
                            logtext "Result: no iptables found in Linux kernel config file"
                        fi
                      else
                        logtext "Result: no Linux configuration file found"
                        Display --indent 2 --text "- Checking iptables in config file" --result "NOT FOUND" --color WHITE
                    fi
                fi
            fi
        fi
    fi
#
#################################################################################
#
    # Test        : FIRE-4512
    # Description : Check iptables for empty ruleset
    if [ ! "${IPTABLESBINARY}" = "" -a ${IPTABLES_ACTIVE} -eq 1 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
    Register --test-no FIRE-4512 --preqs-met ${PREQS_MET} --os Linux --weight L --network NO --root-only YES --description "Check iptables for empty ruleset"
    if [ ${SKIPTEST} -eq 0 ]; then
        FIND=`${IPTABLESBINARY} --list --numeric | egrep -v "^(Chain|target|$)" | wc -l | tr -d ' '`
        if [ "${FIND}" = "0" ]; then
            # Firewall is active, but clearly needs configuration
            FIREWALL_ACTIVE=1
            logtext "Result: iptables ruleset is empty"
            Display --indent 4 --text "- Checking for empty ruleset" --result WARNING --color RED
            ReportWarning ${TEST_NO} "L" "iptables module(s) loaded, but no rules active"
            ReportSuggestion ${TEST_NO} "Disable iptables kernel module if not used or make sure rules are being used"
          else
            logtext "Result: one or more rules are available"
            Display --indent 4 --text "- Checking for empty ruleset" --result OK --color GREEN
        fi
    fi
#
#################################################################################
#
    # Test        : FIRE-4513
    # Description : Check iptables for unused rules
    if [ ! "${IPTABLESBINARY}" = "" -a ${IPTABLES_ACTIVE} -eq 1 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
    Register --test-no FIRE-4513 --preqs-met ${PREQS_MET} --os Linux --weight L --network NO --root-only YES --description "Check iptables for unused rules"
    if [ ${SKIPTEST} -eq 0 ]; then
        FIND=`${IPTABLESBINARY} --list --numeric --line-numbers --verbose | awk '{ if ($2=="0") print $1 }' | xargs`
        if [ "${FIND}" = "" ]; then
            Display --indent 4 --text "- Checking for unused rules" --result OK --color GREEN
            logtext "Result: There are no unused rules present"
          else
            Display --indent 4 --text "- Checking for unused rules" --result WARNING --color YELLOW
            logtext "Result: Found one or more possible unused rules"
            logtext "Description: Unused rules can be a sign that the firewall rules aren't optimized or up-to-date"
            logtext "Note: Sometimes rules aren't triggered but still in use. Keep this in mind before cleaning up rules."
            logtext "Output: iptables rule numbers: ${FIND}"
            #ReportWarning ${TEST_NO} "L" "Found possible unused iptables rules ($FIND)"
            ReportSuggestion ${TEST_NO} "Check iptables rules to see which rules are currently not used"
            logtext "Tip: iptables --list --numeric --line-numbers --verbose"
        fi
    fi
#
#################################################################################
#
    # Test        : FIRE-4518
    # Description : Checking status of pf firewall components
    Register --test-no FIRE-4518 --weight L --network NO --description "Check pf firewall components"
    if [ ${SKIPTEST} -eq 0 ]; then

        PFFOUND=0; PFLOGDFOUND=0

        # Check status with pfctl
        logtext "Test: checking pf status via pfctl"
        if [ ! "${PFCTLBINARY}" = "" ]; then
            FIND=`${PFCTLBINARY} -sa 2>&1 | grep "^Status" | head -1 | awk '{ print $2 }'`
            if [ "${FIND}" = "Enabled" ]; then
                Display --indent 2 --text "- Checking pf status (pfctl)" --result ENABLED --color GREEN
                logtext "Result: pf is enabled"
                PFFOUND=1
                AddHP 3 3
              else
                if [ "${FIND}" = "Disabled" ]; then
                    Display --indent 2 --text "- Checking pf status (pfctl)" --result DISABLED --color RED
                    logtext "Result: pf is disabled"
                    AddHP 0 3
                  else
                    Display --indent 2 --text "- Checking pf status (pfctl)" --result UNKNOWN --color YELLOW
                    ReportException ${TEST_NO} "Unknown status of pf firewall"
                fi
            fi
        fi

        # If we didn't find the status to be enabled, stop searching
        if [ ${PFFOUND} -eq 0 ]; then
            # Check for pf kernel module (FreeBSD and similar)
            logtext "Test: searching for pf kernel module"
            if [ ! "${KLDSTATBINARY}" = "" ]; then
                FIND=`${KLDSTATBINARY} | grep 'pf.ko'`
                if [ "${FIND}" = "" ]; then
                    logtext "Result: Can not find pf KLD"
                  else
                    logtext "Result: pf KLD loaded"
                    PFFOUND=1
                fi
              else
                logtext "Result: no kldstat binary, skipping this part"
            fi

            IsRunning pflogd
            if [ ${RUNNING} -eq 1 ]; then
                logtext "Result: found pflog daemon in process list"
                Display --indent 4 --text "- Checking pflogd status" --result ACTIVE --color GREEN
                PFFOUND=1
                PFLOGDFOUND=1
              else
                logtext "Result: pflog daemon not found in process list"
                Display --indent 4 --text "- Checking pflogd status" --result "NOT FOUND" --color YELLOW
            fi
        fi

        if [ ${PFFOUND} -eq 1 ]; then
            FIREWALL_ACTIVE=1
            FIREWALL_SOFTWARE="pf"
          else
            logtext "Result: pf not running on this system"
            Display --indent 2 --text "- Checking pf" --result "NOT FOUND" --color WHITE
        fi
    fi
#
#################################################################################
#
    # Test        : FIRE-4520
    # Description : Check pf configuration consistency
    if [ ${PFFOUND} -eq 1 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
    Register --test-no FIRE-4520 --preqs-met ${PREQS_MET} --weight L --network NO --description "Check pf configuration consistency"
    if [ ${SKIPTEST} -eq 0 ]; then
        logtext "Test: check /etc/pf.conf"
        # Test for warnings (-n don't load the rules)
        if [ -f /etc/pf.conf ]; then
            logtext "Result: /etc/pf.conf exists"
            # Check results from pfctl
            PFWARNINGS=`pfctl -n -f /etc/pf.conf -vvv 2>&1 | grep -i 'warning'`
            if [ "${PFWARNINGS}" = "" ]; then
                Display --indent 4 --text "- Checking pf configuration consistency" --result OK --color GREEN
                logtext "Result: no pf filter warnings found"
              else
                Display --indent 4 --text "- Checking pf configuration consistency" --result WARNING --color RED
                logtext "Result: found one or more warnings in the pf filter rules"
                ReportWarning ${TEST_NO} "H" "Found one or more warnings in pf configuration file"
                ReportSuggestion ${TEST_NO} "Run 'pfctl -n -f /etc/pf.conf -vvv' to see available pf warnings"
            fi
          else
            logtext "Result: /etc/pf.conf does NOT exist"
        fi
    fi
#
#################################################################################
#
    # Test        : FIRE-4522
    # Description : Check ipchains
#
#################################################################################
#
    # Test        : FIRE-4524
    # Description : Check for CSF (ConfigServer Security & Firewall)
    Register --test-no FIRE-4524 --weight L --network NO --description "Check for CSF presence"
    if [ ${SKIPTEST} -eq 0 ]; then
        FILE="/etc/csf/csf.conf"
        logtext "Test: check ${FILE}"
        if [ -f ${FILE} ]; then
            logtext "Result: ${FILE} exists"
            FIREWALL_ACTIVE=1
            FIREWALL_SOFTWARE="csf"
            Display --indent 2 --text "- Checking CSF status (configuration file)" --result FOUND --color GREEN
          else
            logtext "Result: ${FILE} does NOT exist"
        fi
    fi
#
#################################################################################
#
    # Test        : FIRE-4526
    # Description : Check ipf (Solaris)
    if [ ! "${IPFBINARY}" = "" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
    Register --test-no FIRE-4526 --os Solaris --preqs-met ${PREQS_MET} --weight L --network NO --description "Check ipf status"
    if [ ${SKIPTEST} -eq 0 ]; then
        FIND=`${IPFBINARY} -n -V | grep "^Running" | awk '{ print $2 }'`
        if [ "${FIND}" = "yes" ]; then
            Display --indent 4 --text "- Checking ipf status" --result RUNNING --color GREEN
            logtext "Result: ipf is enabled and running"
            FIREWALL_ACTIVE=1
            FIREWALL_SOFTWARE="ipf"
          else
            Display --indent 4 --text "- Checking ipf status" --result "NOT RUNNING" --color YELLOW
            logtext "Result: ipf is not running"
        fi
    fi
#
#################################################################################
#
    # Test        : FIRE-4530
    # Description : Check ipfw
#
#################################################################################
#
    # Test        : FIRE-4590
    # Description : Check if at least one firewall if active
    Register --test-no FIRE-4590 --weight L --network NO --description "Check firewall status"
    if [ ${SKIPTEST} -eq 0 ]; then
        if [ ${FIREWALL_ACTIVE} -eq 1 ]; then
            Display --indent 2 --text "- Checking host based firewall" --result ACTIVE --color GREEN
            logtext "Result: host based firewall or packet filter is active"
            report "manual[]=Verify if there is a formal process for testing and applying firewall rules"
            report "manual[]=Verify all traffic is filtered the right way between the different security zones"
            report "manual[]=Verify if a list is available with all required services"
            # YYY Solaris ipf (determine default policy)
            report "manual[]=Make sure an explicit deny all is the default policy for all unmatched traffic"
            AddHP 5 5
          else
            Display --indent 2 --text "- Checking host based firewall" --result "NOT ACTIVE" --color YELLOW
            logtext "Result: no host based firewall/packet filter found or configured"
            ReportSuggestion ${TEST_NO} "Configure a firewall/packet filter to filter incoming and outgoing traffic"
            AddHP 0 5
        fi
    fi
#
#################################################################################
#

# Report firewall installed for now, if we found one active. Next step would be determining binaries first and apply additional checks.
report "firewall_installed=${FIREWALL_ACTIVE}"
report "firewall_active=${FIREWALL_ACTIVE}"
report "firewall_software=${FIREWALL_SOFTWARE}"


wait_for_keypress

#
#================================================================================
# Lynis - Copyright 2007-2015, Michael Boelen, CISOfy - https://cisofy.com