lynis/include/tests_crypto

#!/bin/sh

#################################################################################
#
#   Lynis
# ------------------
#
# Copyright 2007-2013, Michael Boelen
# Copyright 2007-2021, CISOfy
#
# Website  : https://cisofy.com
# Blog     : http://linux-audit.com
# GitHub   : https://github.com/CISOfy/lynis
#
# 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.
#
#################################################################################
#
# Cryptography
#
#################################################################################
#
    RNG_FOUND=0
#
#################################################################################
#
    InsertSection "${SECTION_CRYPTOGRAPHY}"
#
#################################################################################
#
    # Test        : CRYP-7902
    # Description : check for expired SSL certificates
    if [ -n "${OPENSSLBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
    Register --test-no CRYP-7902 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check expire date of SSL certificates"
    if [ ${SKIPTEST} -eq 0 ]; then
        COUNT_EXPIRED=0
        COUNT_TOTAL=0
        FOUNDPROBLEM=0
        SKIP=0
        sSSL_PATHS=$(echo ${SSL_CERTIFICATE_PATHS} | ${SEDBINARY} 's/:space:/__space__/g' | ${SEDBINARY} 's/:/ /g')
        sSSL_PATHS=$(echo ${sSSL_PATHS} | ${SEDBINARY} 's/^ //' | ${SORTBINARY} -u)
        LogText "Paths to scan: ${sSSL_PATHS}"

        IGNORE_PATHS_PRINT=$(echo ${SSL_CERTIFICATE_PATHS_TO_IGNORE} | ${SEDBINARY} 's/:/, /g' | ${SEDBINARY} 's/__space__/ /g' | ${SEDBINARY} 's/^ //' | ${SORTBINARY} -u)
        LogText "Paths to ignore: ${IGNORE_PATHS_PRINT}"

        for DIR in ${sSSL_PATHS}; do
            COUNT_DIR=0
            if [ -d ${DIR} ]; then
                FileIsReadable ${DIR}
                if [ ${CANREAD} -eq 1 ]; then
                    LASTSUBDIR=""
                    LogText "Result: found directory ${DIR}"
                    # Search for certificate files
                    FILES=$(${FINDBINARY} ${DIR} -type f 2> /dev/null | ${EGREPBINARY} ".cer$|.crt$|.der$|.pem$|^cert" | ${SORTBINARY} | ${SEDBINARY} 's/ /__space__/g')
                    for FILE in ${FILES}; do
                        FILE=$(echo ${FILE} | ${SEDBINARY} 's/__space__/ /g')
                        # See if we need to skip this path
                        SUBDIR=$(echo ${FILE} | ${AWKBINARY} -F/ 'sub(FS $NF,x)' | ${SEDBINARY} 's/__space__/ /g')
                        # If we discover a new directory, do evaluation
                        #Debug "File   : ${FILE}"
                        #Debug "Lastdir: ${LASTSUBDIR}"
                        #Debug "Curdir : ${SUBDIR}"
                        if [ ! "${SUBDIR}" = "${LASTSUBDIR}" ]; then
                            SKIP=0
                            # Now check if this path is on the to-be-ignored list
                            for D in ${SSL_CERTIFICATE_PATHS_TO_IGNORE}; do
                                if ContainsString "${D}" "${SUBDIR}"; then
                                    SKIP=1
                                    LogText "Result: skipping directory (${SUBDIR}) as it is on ignore list"
                                fi
                            done
                        fi
                        if [ ${SKIP} -eq 0 ]; then
                            #Debug "Testing ${FILE} in path: $SUBDIR"
                            COUNT_DIR=$((COUNT_DIR + 1))
                            FileIsReadable "${FILE}"
                            if [ ${CANREAD} -eq 1 ]; then
                                # Only check the files that are not installed by a package, unless enabled by profile
                                if [ ${SSL_CERTIFICATE_INCLUDE_PACKAGES} -eq 1 ] || ! FileInstalledByPackage "${FILE}"; then
                                    echo ${FILE} | ${EGREPBINARY} -q ".cer$|.der$"
                                    CER_DER=$?
                                    OUTPUT=$(${GREPBINARY} -q 'BEGIN CERT' "${FILE}")
                                    if [ $? -eq 0 -o ${CER_DER} -eq 0 ]; then
                                        LogText "Result: file is a certificate file"
                                        if [ ${CER_DER} -eq 0 ]; then
                                            SSL_DER_OPT="-inform der"
                                        else
                                            SSL_DER_OPT=
                                        fi
                                        FIND=$(${OPENSSLBINARY} x509 -noout ${SSL_DER_OPT} -in "${FILE}" -enddate 2> /dev/null | ${GREPBINARY} "^notAfter")
                                        if [ $? -eq 0 ]; then
                                            # Check certificate where 'end date' has been expired
                                            FIND=$(${OPENSSLBINARY} x509 -noout ${SSL_DER_OPT} -checkend 0 -in "${FILE}" -enddate 2> /dev/null)
                                            EXIT_CODE=$?
                                            CERT_CN=$(${OPENSSLBINARY} x509 -noout ${SSL_DER_OPT} -subject -in "${FILE}" 2> /dev/null | ${SEDBINARY} -e 's/^subject.*CN=\([a-zA-Z0-9\.\-\*]*\).*$/\1/')
                                            CERT_NOTAFTER=$(${OPENSSLBINARY} x509 -noout ${SSL_DER_OPT} -enddate -in "${FILE}" 2> /dev/null | ${AWKBINARY} -F= '{if ($1=="notAfter") { print $2 }}')
                                            Report "certificate[]=${FILE}|${EXIT_CODE}|cn:${CERT_CN};notafter:${CERT_NOTAFTER};|"
                                            if [ ${EXIT_CODE} -eq 0 ]; then 
                                                LogText "Result: certificate ${FILE} seems to be correct and still valid"
                                            else
                                                FOUNDPROBLEM=1
                                                COUNT_EXPIRED=$((COUNT_EXPIRED + 1))
                                                LogText "Result: certificate ${FILE} has been expired"
                                            fi
                                        else
                                            LogText "Result: skipping tests for this file (${FILE}) as it is most likely not a certificate (is it a key file?)"
                                        fi
                                    else
                                        LogText "Result: skipping test for this file (${FILE}) as we could not find 'BEGIN CERT'"
                                    fi
                                fi
                            else
                                LogText "Result: can not read file ${FILE} (no permission)"
                            fi
                        fi
                        LASTSUBDIR="${SUBDIR}"
                    done
                    COUNT_TOTAL=$((COUNT_TOTAL + COUNT_DIR))
                    LogText "Result: found ${COUNT_DIR} certificates in ${DIR}"
                else
                    LogText "Result: can not read path ${DIR} (no permission)"
                fi
            else
                LogText "Result: SSL path ${DIR} does not exist"
            fi
        done
        Report "certificates=${COUNT_TOTAL}"
        LogText "Result: found a total of ${COUNT_TOTAL} certificates"

        if [ ${FOUNDPROBLEM} -eq 0 ]; then
            Display --indent 2 --text "- Checking for expired SSL certificates [${COUNT_EXPIRED}/${COUNT_TOTAL}]" --result "${STATUS_NONE}" --color GREEN
        else
            Display --indent 2 --text "- Checking for expired SSL certificates [${COUNT_EXPIRED}/${COUNT_TOTAL}]" --result "${STATUS_FOUND}" --color RED
            ReportSuggestion "${TEST_NO}" "Check available certificates for expiration"
        fi
    fi

#
#################################################################################
#
    # Test        : CRYP-7930
    # Description : Determine if system uses LUKS block device encryption
    Register --test-no CRYP-7930 --os Linux --weight L --network NO --root-only YES --category security --description "Determine if system uses LUKS block device encryption"
    if [ ${SKIPTEST} -eq 0 ]; then
        CRYPTTABFILE="${ROOTDIR}etc/crypttab"
        FOUND=0

        # cryptsetup only works as root
        if [ -n "${LSBLKBINARY}" ] && [ -n "${CRYPTSETUPBINARY}" ] && [ ${FORENSICS_MODE} -eq 0 ]; then
            for BLOCK_DEV in $(${LSBLKBINARY} --noheadings --list -o NAME 2> /dev/null | cut -d' ' -f1); do
                if ${CRYPTSETUPBINARY} isLuks $(${FINDBINARY} /dev/ -name "${BLOCK_DEV}" 2> /dev/null) 2> /dev/null; then
                    LogText "Result: Found LUKS encrypted block device: ${BLOCK_DEV}"
                    Report "encryption[]=luks,block_device,${BLOCK_DEV}"
                    FOUND=$((FOUND +1))
                else
                    LogText "Result: block device ${BLOCK_DEV} is not LUKS encrypted"
                fi
            done
            unset BLOCK_DEV

        # This will enable us to do a test for forensics or when crypsetup/lsblk are not available
        elif [ -f ${CRYPTTABFILE} ]; then
            LogText "Result: crypttab (${CRYPTTABFILE}) exists"
            DATA=$(${GREPBINARY} "^[a-z]" ${CRYPTTABFILE} | ${TRBINARY} -cd '[:alnum:]_\-=,\n\t ' | ${SEDBINARY} 's/[[:blank:]]/__space__/g')
            for LINE in ${DATA}; do
                LINE=$(echo ${LINE} | ${SEDBINARY} 's/__space__/ /g')
                if ContainsString "luks," "${LINE}"; then
                    PARTITION=$(echo ${LINE} | ${AWKBINARY} '{print $1}' | ${AWKBINARY} -F_ '{print $1}')
                    LogText "Result: Found LUKS encryption on partition ${PARTITION}"
                    Report "encryption[]=luks,partition,${PARTITION}"
                    FOUND=$((FOUND +1))
                fi
            done
            unset DATA LINE PARTITION
        fi

        if [ ${FOUND} -gt 0 ]; then
            Display --indent 2 --text "- Found ${FOUND} LUKS encrypted block devices." --result OK --color WHITE
        fi
        unset FOUND
    fi
#
#################################################################################
#
    # Test        : CRYP-7931
    # Description : Determine if system uses encrypted swap
    if [ -e "${SWAPONBINARY}" -a -e "${CRYPTSETUPBINARY}" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
    Register --test-no CRYP-7931 --preqs-met ${PREQS_MET} --os Linux --weight L --network NO --root-only YES --category security --description "Determine if system uses encrypted swap"
    if [ ${SKIPTEST} -eq 0 ]; then
        ENCRYPTED_SWAPS=0
        UNENCRYPTED_SWAPS=0
        # Redirect errors, as RHEL 5/6 and others don't have the --show option
        SWAPS=$(${SWAPONBINARY} --show=NAME --noheadings 2> /dev/null)
        if [ $? -eq 0 ]; then
            for BLOCK_DEV in ${SWAPS}; do
                if ${CRYPTSETUPBINARY} isLuks "${BLOCK_DEV}" 2> /dev/null; then
                    LogText "Result: Found LUKS encrypted swap device: ${BLOCK_DEV}"
                    ENCRYPTED_SWAPS=$((ENCRYPTED_SWAPS + 1))
                    Report "encrypted_swap[]=${BLOCK_DEV},LUKS"
                elif ${CRYPTSETUPBINARY} status "${BLOCK_DEV}" 2> /dev/null | ${GREPBINARY} -q "cipher:"; then
                    LogText "Result: Found non-LUKS encrypted swap device: ${BLOCK_DEV}"
                    ENCRYPTED_SWAPS=$((ENCRYPTED_SWAPS + 1))
                    Report "encrypted_swap[]=${BLOCK_DEV},other"
                else
                    LogText "Result: Found unencrypted swap device: ${BLOCK_DEV}"
                    UNENCRYPTED_SWAPS=$((UNENCRYPTED_SWAPS +1))
                    Report "non_encrypted_swap[]=${BLOCK_DEV}"
                fi
            done
            Display --indent 2 --text "- Found ${ENCRYPTED_SWAPS} encrypted and ${UNENCRYPTED_SWAPS} unencrypted swap devices in use." --result OK --color WHITE
        else
            LogText "Result: skipping testing as swapon returned an error."
        fi
    fi
#
#################################################################################
#
    # Test        : CRYP-8002
    # Description : Gather available kernel entropy
    Register --test-no CRYP-8002 --os Linux --weight L --network NO --root-only NO --category security --description "Gather available kernel entropy"
    if [ ${SKIPTEST} -eq 0 ]; then
        if [ -f ${ROOTDIR}proc/sys/kernel/random/entropy_avail ]; then
            DATA=$(${AWKBINARY} '$1 ~ /^[0-9]+$/ {print $1}' ${ROOTDIR}proc/sys/kernel/random/entropy_avail)
            if [ -n "${DATA}" ]; then
                LogText "Result: found kernel entropy value of ${DATA}"
                Report "kernel_entropy=${DATA}"
                if [ ${DATA} -gt 200 ]; then
                    Display --indent 2 --text "- Kernel entropy is sufficient" --result "${STATUS_YES}" --color GREEN
                else
                    Display --indent 2 --text "- Kernel entropy is sufficient" --result "${STATUS_NO}" --color YELLOW
                    # TODO - enable suggestion when information on website is available
                fi
            fi
        fi
    fi
#
#################################################################################
#
    # Test        : CRYP-8004
    # Description : Test for presence of hardware random number generators
    Register --test-no CRYP-8004 --os Linux --weight L --network NO --root-only NO --category security --description "Presence of hardware random number generators"
    if [ ${SKIPTEST} -eq 0 ]; then
        LogText "Test: looking for ${ROOTDIR}sys/class/misc/hw_random/rng_current"
        if [ -f "${ROOTDIR}sys/class/misc/hw_random/rng_current" ]; then
            DATA=$(${HEADBINARY} -n 1 ${ROOTDIR}sys/class/misc/hw_random/rng_current | ${TRBINARY} -d '[[:cntrl:]]')
            if [ "${DATA}" != "none" ]; then
                LogText "Result: positive match, found RNG: ${DATA}"
                if IsRunning "rngd"; then
                    Display --indent 2 --text "- HW RNG & rngd" --result "${STATUS_YES}" --color GREEN
                    LogText "Result: rngd is running"
                    RNG_FOUND=1
                else
                    Display --indent 2 --text "- HW RNG & rngd" --result "${STATUS_NO}" --color YELLOW
                    # TODO - enable suggestion when website has listing for this control
                    # ReportSuggestion "${TEST_NO}" "Utilize hardware random number generation by running rngd"
                fi
            else
                Display --indent 2 --text "- HW RNG & rngd" --result "${STATUS_NO}" --color YELLOW
                LogText "Result: no HW RNG available"
            fi
        else
            Display --indent 2 --text "- HW RNG & rngd" --result "${STATUS_NO}" --color RED
            LogText "Result: could not find ${ROOTDIR}sys/class/misc/hw_random/rng_current"
        fi
    fi
#
#################################################################################
#
    # Test        : CRYP-8005
    # Description : Test for presence of software pseudo random number generators
    Register --test-no CRYP-8005 --os Linux --weight L --network NO --root-only NO --category security --description "Presence of software pseudo random number generators"
    if [ ${SKIPTEST} -eq 0 ]; then
        LogText "Test: looking for software pseudo random number generators"
        FOUND=""
        for SERVICE in audio-entropyd haveged jitterentropy-rngd; do
            # Using --full as jitterentropy-rngd would otherwise not match
            if IsRunning --full "${SERVICE}"; then
                FOUND="${FOUND} ${SERVICE}"
            fi
        done
        if [ -z "${FOUND}" ]; then
            Display --indent 2 --text "- SW prng" --result "${STATUS_NO}" --color YELLOW
            # ReportSuggestion "${TEST_NO}" "Utilize software pseudo random number generators"
        else
            RNG_FOUND=1
            Display --indent 2 --text "- SW prng" --result "${STATUS_YES}" --color GREEN
            LogText "Result: found ${FOUND} running"
        fi
    fi
#
#################################################################################
#
    # Test        : CRYP-8006
    # Description : Check that the MemoryOverwriteRequest-bit is set to protect against cold-boot attacks
    Register --test-no CRYP-8006 --os Linux --weight L --network NO --root-only NO --category security --description "MemoryOverwriteRequest-bit set"
    if [ ${SKIPTEST} -eq 0 ]; then
        MOR_CONTROL="${ROOTDIR}sys/firmware/efi/efivars/MemoryOverwriteRequestControl-e20939be-32d4-41be-a150-897f85d49829"
        LogText "Test: looking for ${MOR_CONTROL}"
        if [ -f "${MOR_CONTROL}" ]; then
            DATA=$(od -An --skip-bytes=4 "$MOR_CONTROL")
            if [ "$DATA" = " 000001" ]; then
                LogText "Result: MOR-bit set"
                Display --indent 2 --text "MOR-bit set" --result "${STATUS_YES}" --color GREEN
            elif [ "$DATA" = " 000000" ]; then
                LogText "Result: MOR-bit not set!"
                Display --indent 2 --text "MOR-bit set" --result "${STATUS_NO}" --color RED
            else
                LogText "Result: MOR-bit unknown. Found: $DATA"
                Display --indent 2 --text "MOR-bit set" --result "${STATUS_UNKNOWN}" --color YELLOW
            fi
        else
            LogText "Result: could not find ${MOR_CONTROL}"
            Display --indent 2 --text "- MOR variable not found" --result "${STATUS_WEAK}" --color WHITE
        fi
    fi
#
#################################################################################
#
    Report "rng_found=${RNG_FOUND}"
#
#################################################################################
#

WaitForKeyPress

#
#================================================================================
# Lynis - Security Auditing and System Hardening for Linux and UNIX - https://cisofy.com