lynis/include/tests_kernel_hardening

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#!/bin/sh
#################################################################################
#
# Lynis
# ------------------
#
# Copyright 2007-2013, Michael Boelen
# Copyright 2007-2019, 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.
#
#################################################################################
#
# Kernel
#
#################################################################################
#
InsertSection "Kernel Hardening"
#
#################################################################################
#
# Test : KRNL-6000
# Description : Check sysctl parameters
# Sysctl : net.ipv4.icmp_ingore_bogus_error_responses (=1)
if [ ! "${SYSCTL_READKEY}" = "" ]; then PREQS_MET="YES"; else PREQS_MET="NO"; fi
Register --test-no KRNL-6000 --preqs-met ${PREQS_MET} --weight L --network NO --category security --description "Check sysctl key pairs in scan profile"
if [ ${SKIPTEST} -eq 0 ]; then
FOUND=0
DATA_TO_SCAN=""
N=0
Display --indent 2 --text "- Comparing sysctl key pairs with scan profile"
# First scan optional profiles only (ignore default and custom)
for PROFILE in ${PROFILES}; do
FILE=$(echo ${PROFILE} | ${AWKBINARY} -F/ '{print $NF}')
if [ ! "${FILE}" = "default.prf" -a ! "${FILE}" = "custom.prf" ]; then
FIND=$(${GREPBINARY} "^config-data=sysctl;" ${PROFILE} | ${SEDBINARY} 's/ /-space-/g')
DATA_TO_SCAN="${DATA_TO_SCAN} ${FIND}"
fi
done
# Scan custom profile
if [ -n "${CUSTOM_PROFILE}" ]; then
FIND=$(${GREPBINARY} "^config-data=sysctl;" ${CUSTOM_PROFILE} | ${SEDBINARY} 's/ /-space-/g')
for LINE in ${FIND}; do
SYSCTLKEY=$(echo ${LINE} | ${AWKBINARY} -F\; '{ print $2 }')
HAS_KEY=$(echo ${DATA_TO_SCAN} | ${GREPBINARY} ";${SYSCTLKEY};")
if [ $? -gt 0 ]; then DATA_TO_SCAN="${DATA_TO_SCAN} ${LINE}"; fi
done
fi
# Last, use data from default profile
if [ -n "${DEFAULT_PROFILE}" ]; then
FIND=$(${GREPBINARY} "^config-data=sysctl;" ${DEFAULT_PROFILE} | ${SEDBINARY} 's/ /-space-/g')
for LINE in ${FIND}; do
SYSCTLKEY=$(echo ${LINE} | ${AWKBINARY} -F\; '{ print $2 }')
HAS_KEY=$(echo ${DATA_TO_SCAN} | ${GREPBINARY} ";${SYSCTLKEY};")
if [ $? -gt 0 ]; then DATA_TO_SCAN="${DATA_TO_SCAN} ${LINE}"; fi
done
fi
# Sort the results
DATA_TO_SCAN=$(echo ${DATA_TO_SCAN} | ${TRBINARY} ' ' '\n' | sort)
for line in ${DATA_TO_SCAN}; do
tFINDkey=$(echo ${line} | ${AWKBINARY} -F\; '{ print $2 }')
if ! SkipAtomicTest "${TEST_NO}:${tFINDkey}"; then
tFINDexpvalue=$(echo ${line} | ${AWKBINARY} -F\; '{ print $3 }' | ${TRBINARY} '|' ' ')
tFINDhp=$(echo ${line} | ${AWKBINARY} -F\; '{ print $4 }' | ${GREPBINARY} "[0-9]")
tFINDdesc=$(echo ${line} | ${AWKBINARY} -F\; '{ print $5 }' | ${SEDBINARY} 's/-space-/ /g')
tFINDcurvalue=$(${SYSCTL_READKEY} ${tFINDkey} 2> /dev/null)
if [ -n "${tFINDcurvalue}" ]; then
positive_match=0
for value in ${tFINDexpvalue}; do
if [ "${value}" = "${tFINDcurvalue}" ]; then
positive_match=1
fi
done
if [ ${positive_match} -eq 1 ]; then
LogText "Result: sysctl key ${tFINDkey} contains equal expected and current value (${tFINDexpvalue})"
Display --indent 4 --text "- ${tFINDkey} (exp: ${tFINDexpvalue})" --result "${STATUS_OK}" --color GREEN
AddHP ${tFINDhp} ${tFINDhp}
else
LogText "Result: sysctl key ${tFINDkey} has a different value than expected in scan profile. Expected=${tFINDexpvalue}, Real=${tFINDcurvalue}"
Display --indent 4 --text "- ${tFINDkey} (exp: ${tFINDexpvalue})" --result DIFFERENT --color RED
AddHP 0 ${tFINDhp}
FOUND=1
N=$((N + 1))
ReportDetails --test "${TEST_NO}" --service "sysctl" --field "${tFINDkey}" --value "${tFINDcurvalue}" --preferredvalue "${tFINDexpvalue}" --description "${tFINDdesc}"
fi
else
LogText "Result: key ${tFINDkey} does not exist on this machine"
fi
else
LogText "Skipped test for ${tFINDkey} via profile"
fi
done
# Add suggestion if one or more sysctls have a different value than scan profile
if [ ${FOUND} -eq 1 ]; then
LogText "Result: found ${N} keys that can use tuning, according scan profile"
ReportSuggestion ${TEST_NO} "One or more sysctl values differ from the scan profile and could be tweaked" "" "Change sysctl value or disable test (skip-test=${TEST_NO}:<sysctl-key>)"
fi
fi
#
#################################################################################
#
WaitForKeyPress
#
#================================================================================
# Lynis - Security Auditing and System Hardening for Linux and UNIX - https://cisofy.com