Edit: /usr/share/lynis/include/tests_kerberos (8063B)
#!/bin/sh
InsertSection "${SECTION_KERBEROS}"
#
#########################################################################
#
# Test : KRB-1000
# Description : Check that Kerberos principals have passwords that expire
Register --test-no KRB-1000 --weight L --network NO --description "Check for Kerberos KDC tools"
if [ -n "${KADMINLOCALBINARY}" ] && [ -n "${KDB5UTILBINARY}" ]
then
PREQS_MET="YES"
# Make sure krb5 debugging doesn't mess up the output
unset KRB5_TRACE
PRINCS="$(${KADMINLOCALBINARY} listprincs 2>/dev/null | ${TRBINARY:-tr} '\n' ' ')"
if [ -z "${PRINCS}" ]
then
PREQS_MET="NO"
fi
else
PREQS_MET="NO"
fi
if [ "${PREQS_MET}" = "YES" ]; then
Display --indent 2 --text "- Check for Kerberos KDC and principals" --result "${STATUS_FOUND}" --color GREEN
else
Display --indent 2 --text "- Check for Kerberos KDC and principals" --result "${STATUS_NOT_FOUND}" --color WHITE
fi
# Test : KRB-1010
# Description : Check that Kerberos principals have passwords that expire
Register --test-no KRB-1010 --preqs-met ${PREQS_MET} --weight L --network NO --description "Check that Kerberos principals have passwords that expire"
if [ ${SKIPTEST} -eq 0 ]; then
FOUND=0
for I in ${PRINCS}
do
FIND="$(${KADMINLOCALBINARY} getprinc "${I}" | ${GREPBINARY} '^Password expiration date:')"
if [ "${FIND}" = "Password expiration date: [never]" ]
then
LogText "Result: Kerberos principal ${I} has a password/key that never expires"
FOUND=1
fi
done
if [ ${FOUND} -eq 1 ]; then
Display --indent 4 --text "- Principals without expiring password" --result "${STATUS_WARNING}" --color RED
ReportSuggestion "${TEST_NO}" "Make sure all your Kerberos principals have expiring passwords"
else
Display --indent 4 --text "- Principals without expiring password" --result "${STATUS_OK}" --color GREEN
fi
fi
#
#################################################################################
#
# Test : KRB-1020
# Description : Check last password change for Kerberos principals
Register --test-no KRB-1020 --preqs-met ${PREQS_MET} --weight L --network NO --description "Check last password change for Kerberos principals"
if [ ${SKIPTEST} -eq 0 ]; then
FOUND=0
for I in ${PRINCS}
do
FIND="$(${KADMINLOCALBINARY} getprinc "${I}" | ${SEDBINARY} -n '/^Last password change:\s\+/s/^Last password change:\s\+//p')"
if [ "${FIND}" = "[never]" ]
then
LogText "Result: Kerberos principal ${I} has a password/key that has never been changed"
FOUND=1
else
J="$(date -d "${FIND}" +%s)"
if [ ${J} -lt $((NOW - 60 * 60 * 24 * 365)) ]
then
LogText "Result: Kerberos principal ${I} has had a password/key change over a year ago"
FOUND=1
fi
fi
done
if [ ${FOUND} -eq 1 ]; then
Display --indent 4 --text "- Principals with late password change" --result "${STATUS_WARNING}" --color RED
ReportSuggestion "${TEST_NO}" "Enforce frequent password/key change for your Kerberos principals"
else
Display --indent 4 --text "- Principals with late password change" --result "${STATUS_OK}" --color GREEN
fi
fi
#
#################################################################################
#
# Test : KRB-1030
# Description : Check that Kerberos principals have a policy associated to them
Register --test-no KRB5-1030 --preqs-met ${PREQS_MET} --weight L --network NO --description "Check that Kerberos principals have a policy associated to them"
if [ ${SKIPTEST} -eq 0 ]; then
FOUND=0
for I in ${PRINCS}
do
FIND="$(${KADMINLOCALBINARY} getprinc "${I}" | ${GREPBINARY} '^Policy:')"
if [ "${FIND}" = "Policy: [none]" ]
then
LogText "Result: Kerberos principal ${I} does not have a policy associated to it"
FOUND=1
fi
done
if [ ${FOUND} -eq 1 ]; then
Display --indent 4 --text "- Principals without associated policy" --result "${STATUS_WARNING}" --color RED
ReportSuggestion "${TEST_NO}" "Make sure all your Kerberos principals have a policy associated to them"
else
Display --indent 4 --text "- Principals without associated policy" --result "${STATUS_OK}" --color GREEN
fi
fi
#
#################################################################################
#
# Test : KRB-1040
# Description : Check various attributes for Kerberos principals
Register --test-no KRB5-1040 --preqs-met ${PREQS_MET} --weight L --network NO --description "Check various attributes for Kerberos principals"
if [ ${SKIPTEST} -eq 0 ]; then
FOUND=0
for I in ${PRINCS}
do
J="$(${KADMINLOCALBINARY} getprinc "${I}" | ${SEDBINARY} -n 's/^Attributes:\s\+\(.\+\)$/\1/p')"
if ContainsString "^K/M@" "${I}" || \
ContainsString "^kadmin/admin@" "${I}" || \
ContainsString "^kadmin/changepw@" "${I}" || \
ContainsString "^krbtgt/" "${I}"
then
if ! ContainsString "\bLOCKDOWN_KEYS\b" "${J}"
then
LogText "Result: Sensitive Kerberos principal ${I} does not have the lockdown_keys attribute"
FOUND=1
fi
elif ContainsString "/admin@" "${I}"
then
if ! ContainsString "\bDISALLOW_TGT_BASED\b" "${J}"
then
LogText "Result: Kerberos admin principal ${I} does not have the disallow_tgt_based attribute"
FOUND=1
fi
elif ContainsString "^[^/$]+@" "${I}"
then
if ! ContainsString "\bREQUIRES_PRE_AUTH\b.+\bDISALLOW_SVR\b" "${J}"
then
LogText "Result: Regular Kerberos user principal ${I} does not have the requires_pre_auth and/or the disallow_svr attribute"
FOUND=1
fi
fi
done
if [ ${FOUND} -eq 1 ]; then
Display --indent 4 --text "- Checking principals for various attributes" --result "${STATUS_WARNING}" --color RED
ReportSuggestion "${TEST_NO}" "Harden your Kerberos principals with appropriate attributes"
else
Display --indent 4 --text "- Checking principals for various attributes" --result "${STATUS_OK}" --color GREEN
fi
fi
#
#################################################################################
#
# Test : KRB-1050
# Description : Check for weak crypto
Register --test-no KRB-1050 --preqs-met ${PREQS_MET} --weight L --network NO --description "Check for weak crypto"
if [ ${SKIPTEST} -eq 0 ]; then
FIND=$(${KDB5UTILBINARY} tabdump keyinfo | ${AWKBINARY} '$4 ~ /(des|arcfour|cbc|sha1)/{print$1,$4}')
if [ -n "${FIND}" ]; then
while read I J
do
LogText "Result: Kerberos principal ${I} has a key with weak cryptographic algorithm ${J}"
done << EOF
${FIND}
EOF
Display --indent 4 --text "- Principals with weak crypto" --result "${STATUS_WARNING}" --color RED
ReportSuggestion "${TEST_NO}" "Remove weak (des|arcfour|cbc|sha1) cryptographic keys from principals"
else
Display --indent 4 --text "- Principals with weak crypto" --result "${STATUS_OK}" --color GREEN
fi
fi
#
#################################################################################
#
unset PRINCS
unset I
unset J
#EOF