lynis/include/tests_ssh

#!/bin/sh

#################################################################################
#
#   Lynis
# ------------------
#
# Copyright 2007-2015, Michael Boelen (michael@rootkit.nl), The Netherlands
# Web site: http://www.rootkit.nl
#
# 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.
#
#################################################################################
#
# SSH
#
#################################################################################
#
    SSH_DAEMON_CONFIG_LOCS="/etc /etc/ssh /usr/local/etc/ssh /opt/csw/etc/ssh"
    SSH_DAEMON_CONFIG=""
    SSH_DAEMON_PORT=""
    SSH_DAEMON_RUNNING=0
#
#################################################################################
#
    InsertSection "SSH Support"
#
#################################################################################
#
    # Test        : SSH-7402
    # Description : Check for a running SSH daemon
    Register --test-no SSH-7402 --weight L --network NO --description "Check for running SSH daemon"
    if [ ${SKIPTEST} -eq 0 ]; then
        logtext "Test: Searching for a SSH daemon"
        IsRunning sshd
        if [ ${RUNNING} -eq 1 ]; then
            SSH_DAEMON_RUNNING=1
            Display --indent 2 --text "- Checking running SSH daemon" --result FOUND --color GREEN
          else
            Display --indent 2 --text "- Checking running SSH daemon" --result "NOT FOUND" --color WHITE
        fi
    fi
#
#################################################################################
#
    # Test        : SSH-7404
    # Description : Determine SSH daemon configuration file location
    if [ ${SSH_DAEMON_RUNNING} -eq 1 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
    Register --test-no SSH-7404 --preqs-met ${PREQS_MET} --weight L --network NO --description "Check SSH daemon file location"
    if [ ${SKIPTEST} -eq 0 ]; then
        FOUND=0
        logtext "Test: searching for sshd_config file"
        for I in ${SSH_DAEMON_CONFIG_LOCS}; do
            if [ -f "${I}/sshd_config" ]; then
              logtext "Result: ${I}/sshd_config exists"
              if [ ${FOUND} -eq 1 ]; then
                  ReportException "${TEST_NO}:01"
                  logtext "Result: we already had found another sshd_config file. Using this new file then."
              fi
              FileIsReadable ${I}/sshd_config
              if [ ${CANREAD} -eq 1 ]; then
                  FOUND=1
                  SSH_DAEMON_CONFIG="${I}/sshd_config"
                else
                  logtext "Result: can not read ${I}/sshd_config file (no permission)"
              fi
            fi
        done
        if [ "${SSH_DAEMON_CONFIG}" = "" ]; then
            logtext "Result: No sshd configuration found"
            Display --indent 4 --text "- Searching SSH configuration" --result "NOT FOUND" --color YELLOW
            ReportException "${TEST_NO}:1" "SSH daemon is running, but no readable configuration file found"
          else
            logtext "Result: using last found configuration file: ${SSH_DAEMON_CONFIG}"
            Display --indent 4 --text "- Searching SSH configuration" --result FOUND --color GREEN
        fi
    fi
#
#################################################################################
#
#    # Test        : SSH-7406
#    # Description : Check for a running SSH daemon
#    if [ ${SSH_DAEMON_RUNNING} -eq 1 -a ! "${SSH_DAEMON_CONFIG}" = "" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
#    Register --test-no SSH-7406 --preqs-met ${PREQS_MET} --weight L --network NO --description "SSH daemon listening port"
#    if [ ${SKIPTEST} -eq 0 ]; then
#        logtext "Test: Searching for a SSH daemon"
#        CheckOption "^Port " ${SSH_DAEMON_CONFIG}
#        if [ ${FOUND} -eq 1 ]; then
#            FIND=`echo ${FIND} | awk '{ if ($1=="Port") { print $2 }}'`
#            # Check if this output is numeric and usuable for later (e.g. in netstat output)
#            Display --indent 2 --text "- Checking SSH listening port" --result FOUND --color GREEN
#            logtext "Result: setting port number to ${FIND}"
#            SSH_DAEMON_PORT="${FIND}"
#          else
#            Display --indent 2 --text "- Checking SSH listening port" --result "NOT FOUND" --color WHITE
#            logtext "Result: setting port to default number, as no other port has been configured"
#            SSH_DAEMON_PORT="22"
#        fi
#    fi
#
#################################################################################
#
    # Test        : SSH-7408
    # Description : Check SSH specific defined options
    if [ ${SSH_DAEMON_RUNNING} -eq 1 -a ! "${SSH_DAEMON_CONFIG}" = "" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
    Register --test-no SSH-7408 --preqs-met ${PREQS_MET} --weight L --network NO --description "Check SSH defined options"
    if [ ${SKIPTEST} -eq 0 ]; then
        logtext "Test: Checking all specific defined options in ${SSH_DAEMON_CONFIG}"
        FIND=`cat ${SSH_DAEMON_CONFIG} | grep -v "^#" | grep -v "^$" | ${AWKBINARY} '{gsub("\t"," ");print}' | sed 's/ /!space!/g'`
        for I in ${FIND}; do
            I=`echo ${I} | sed 's/!space!/ /g'`
            logtext "Found SSH option: ${I}"
        done
        Display --indent 4 --text "- Checking defined SSH options" --result "DONE" --color GREEN
    fi
#
#################################################################################
#
    # Test        : SSH-7412
    # Description : Check SSH PermitRootLogin option
    if [ ${SSH_DAEMON_RUNNING} -eq 1 -a ! "${SSH_DAEMON_CONFIG}" = "" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
    Register --test-no SSH-7412 --preqs-met ${PREQS_MET} --weight L --network NO --description "Check SSH option: PermitRootLogin"
    if [ ${SKIPTEST} -eq 0 ]; then
        logtext "Test: check PermitRootLogin option"
        FIND=`cat ${SSH_DAEMON_CONFIG} | grep "^PermitRootLogin" | awk '{ print $2 }'`
        if [ "${FIND}" = "yes" -o "${FIND}" = "YES" -o "${FIND}" = "Yes" ]; then
            logtext "Result: PermitRootLogin is enabled, root can login directly"
            Display --indent 4 --text "- SSH option: PermitRootLogin" --result WARNING --color RED
            ReportWarning ${TEST_NO} "M" "Root can directly login via SSH"
            AddHP 0 3
          else
            # YYY add test for DenyUsers root
            if [ "${FIND}" = "no" -o "${FIND}" = "No" ]; then
                logtext "Result: PermitRootLogin is disabled. Root can't login directly"
                Display --indent 4 --text "- SSH option: PermitRootLogin" --result DISABLED --color GREEN
                AddHP 3 3
            elif [ "${FIND}" = "without-password" ]; then
                # Check if password authentication is disabled for root user, so this option is used properly
                logtext "Result: PermitRootLogin is disabled. Root can't login directly"
                Display --indent 4 --text "- SSH option: PermitRootLogin (without-password)" --result OK --color GREEN
                AddHP 3 3
              else
                logtext "Result: Value of PermitRootLogin is unknown (not defined)"
                Display --indent 4 --text "- SSH option: PermitRootLogin" --result DEFAULT --color WHITE
            fi
        fi
    fi
#
#################################################################################
#
    # Test        : SSH-7414
    # Description : Check SSH Protocol option
    if [ ${SSH_DAEMON_RUNNING} -eq 1 -a ! "${SSH_DAEMON_CONFIG}" = "" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
    Register --test-no SSH-7414 --preqs-met ${PREQS_MET} --weight L --network NO --description "Check SSH option: Protocol"
    if [ ${SKIPTEST} -eq 0 ]; then
        logtext "Test: check allowed SSH protocol versions"
        FIND=`cat ${SSH_DAEMON_CONFIG} | grep "^Protocol" | awk '{ print $2 }'`
        if [ "${FIND}" = "1" -o "${FIND}" = "2,1" -o "${FIND}" = "1,2" ]; then
            logtext "Result: Protocol option is set to allow SSH protocol version 1"
            Display --indent 4 --text "- SSH option: Protocol" --result WARNING --color RED
            ReportWarning ${TEST_NO} "M" "SSH protocol version 1 is allowed"
            AddHP 0 3
          else
            if [ "${FIND}" = "2" ]; then
                logtext "Result: only protocol 2 is allowed"
                Display --indent 4 --text "- SSH option: Protocol" --result OK --color GREEN
                AddHP 3 3
              else
                logtext "Result: value of Protocol is unknown (not defined)"
                Display --indent 4 --text "- SSH option: Protocol" --result DEFAULT --color WHITE
            fi
        fi
    fi
#
#################################################################################
#
    # Test        : SSH-7416
    # Description : Check SSH StrictModes option
    if [ ${SSH_DAEMON_RUNNING} -eq 1 -a ! "${SSH_DAEMON_CONFIG}" = "" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
    Register --test-no SSH-7416 --preqs-met ${PREQS_MET} --weight L --network NO --description "Check SSH option: StrictModes"
    if [ ${SKIPTEST} -eq 0 ]; then
        logtext "Test: Check configured StrictModes option"
        FIND=`cat ${SSH_DAEMON_CONFIG} | grep "^StrictModes" | awk '{ print $2 }'`
        if [ "${FIND}" = "no" -o "${FIND}" = "NO" -o "${FIND}" = "No" ]; then
            logtext "Result: StrictModes option is set to 'no', which means file permissions are NOT checked"
            Display --indent 4 --text "- SSH option: StrictModes" --result WARNING --color RED
            ReportWarning ${TEST_NO} "M" "StrictModes is turned off"
            ReportSuggestion ${TEST_NO} "Check StrictModes option in sshd_config"
            AddHP 0 3
          else
            if [ "${FIND}" = "yes" -o "${FIND}" = "YES" -o "${FIND}" = "Yes" ]; then
                logtext "Result: StrictModes active, file permissions are checked"
                Display --indent 4 --text "- SSH option: StrictModes" --result OK --color GREEN
                AddHP 3 3
              else
                logtext "Result: value of StrictModes is unknown (not defined)"
                Display --indent 4 --text "- SSH option: StrictModes" --result DEFAULT --color WHITE
            fi
        fi
    fi
#
#################################################################################
#
    # Test        : SSH-7418
    # Description : Check SSH Port option
#    if [ ${SSH_DAEMON_RUNNING} -eq 1 -a ! "${SSH_DAEMON_CONFIG}" = "" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
#    Register --test-no SSH-7418 --preqs-met ${PREQS_MET} --weight L --network NO --description "Check SSH option: Port"
#    if [ ${SKIPTEST} -eq 0 ]; then
#	logtext "Test: check allowed SSH protocol versions"
#	FIND=`cat ${SSH_DAEMON_CONFIG} | grep "^Port" | awk '{ if ($2!="22") { print $2 } }'`
#	if [ "${FIND}" = "1" -o "${FIND}" = "2,1" -o "${FIND}" = "1,2" ]; then
#	    logtext "Result: Protocol option is set to allow SSH protocol version 1"
#	    Display --indent 4 --text "- SSH option: Protocol" --result WARNING --color RED
#            ReportWarning ${TEST_NO} "M" "SSH protocol version 1 is allowed"
#	    AddHP 0 3
#	  else
#	    if [ "${FIND}" = "2" ]; then
#	        logtext "Result: only protocol 2 is allowed"
#	        Display --indent 4 --text "- SSH option: Protocol" --result OK --color GREEN
#		AddHP 3 3
#	      else	
#	        logtext "Result: value of Protocol is unknown (not defined)"
#	        Display --indent 4 --text "- SSH option: Protocol" --result DEFAULT --color WHITE
#	    fi
#	fi
#    fi
#
#################################################################################
#
    # Test        : SSH-7440
    # Description : AllowUsers / AllowGroups
    # Goal        : Check if only a specific amount of users/groups can log in to the system
    if [ ${SSH_DAEMON_RUNNING} -eq 1 -a ! "${SSH_DAEMON_CONFIG}" = "" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
    Register --test-no SSH-7440 --preqs-met ${PREQS_MET} --weight L --network NO --description "Check SSH option: AllowUsers and AllowGroups"
    if [ ${SKIPTEST} -eq 0 ]; then
        FOUND=0
        # AllowUsers
        FIND=`egrep "^AllowUsers" ${SSH_DAEMON_CONFIG} | awk '{ print $2 }'`
        if [ ! "${FIND}" = "" ]; then
            logtext "Result: AllowUsers set, with value ${FIND}"
            Display --indent 4 --text "- SSH option: AllowUsers" --result FOUND --color GREEN
            FOUND=1
          else
            logtext "Result: AllowUsers is not set"
            Display --indent 4 --text "- SSH option: AllowUsers" --result "NOT FOUND" --color WHITE
        fi

        # AllowGroups
        FIND=`egrep "^AllowGroups" ${SSH_DAEMON_CONFIG} | awk '{ print $2 }'`
        if [ ! "${FIND}" = "" ]; then
            logtext "Result: AllowUsers set ${FIND}"
            Display --indent 4 --text "- SSH option: AllowGroups" --result FOUND --color GREEN
            FOUND=1
          else
            logtext "Result: AllowGroups is not set"
            Display --indent 4 --text "- SSH option: AllowGroups" --result "NOT FOUND" --color WHITE
        fi

        if [ ${FOUND} -eq 1 ]; then
            logtext "Result: SSH is limited to a specific set of users, which is good"
            AddHP 2 2
          else
            logtext "Result: SSH has no specific user or group limitation. Most likely all valid users can SSH to this machine."
            AddHP 0 1
        fi
    fi
#
#################################################################################
#
    # Test        : SSH-7464
    # Description : HashKnownHosts
    #if [ ${SSH_DAEMON_RUNNING} -eq 1 -a ! "${SSH_DAEMON_CONFIG}" = "" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
    #Register --test-no SSH-7464 --preqs-met ${PREQS_MET} --weight L --network NO --description "Check SSH option: HashKnownHosts"
    #if [ ${SKIPTEST} -eq 0 ]; then
    # /etc/ssh/ssh_config
    #            ReportSuggestion ${TEST_NO} "HashKnownHosts option can migitate worm attacks"
    #AddHP 2 2
    #fi
#
#################################################################################
#
    # Test        : SSH-7480
    # Description : AllowUsers / AllowGroups
    # Goal        : Scan SSH daemon
    #if [ ! ${SSHKEYSCANBINARY} = "" -a ${SSH_DAEMON_RUNNING} -eq 1 ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
    #Register --test-no SSH-7480 --preqs-met ${PREQS_MET} --weight L --network NO --description "Check SSH option: AllowUsers and AllowGroups"
    #if [ ${SKIPTEST} -eq 0 ]; then
    # First determine what port the local instance of SSH daemon is running on. If unknown, use port 22
    # FIND=`${SSHKEYSCANBINARY} localhost 2>&1 | grep OpenSSH | egrep -i "bsd|debian|ubuntu|redhat"`
#
#################################################################################
#
    # sshd -T can provide additional insights
#
#################################################################################
#
report "ssh_daemon_running=${SSH_DAEMON_RUNNING}"
#report "ssh_daemon_port=${SSH_DAEMON_PORT}"

wait_for_keypress

#
#================================================================================
# Lynis - Copyright 2007-2015, Michael Boelen - www.rootkit.nl - The Netherlands