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Merge pull request #1456 from pyllyukko/krb5-plugin 

Added initial version of a Kerberos plugin
This commit is contained in:
Michael Boelen 2024-05-15 22:12:49 +02:00 committed by GitHub
parent 24679bee9a 5182ce31fb
commit ab00091d21
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GPG Key ID: B5690EEEBB952194
5 changed files with 193 additions and 1 deletions
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1
db/languages/en
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@ -63,6 +63,7 @@ SECTION_USB_DEVICES="USB Devices"
SECTION_USERS_GROUPS_AND_AUTHENTICATION="Users, Groups and Authentication"
SECTION_VIRTUALIZATION="Virtualization"
SECTION_WEBSERVER="Software: webserver"
SECTION_KERBEROS="Kerberos"
STATUS_ACTIVE="ACTIVE"
STATUS_CHECK_NEEDED="CHECK NEEDED"
STATUS_DEBUG="DEBUG"

1
default.prf
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@ -144,6 +144,7 @@ plugin=software
plugin=system-integrity
plugin=systemd
plugin=users
plugin=krb5
# Disable a particular plugin (will overrule an enabled plugin)
#disable-plugin=authentication

2
include/binaries
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@ -196,6 +196,8 @@
iptables-save) IPTABLESSAVEBINARY="${BINARY}"; LogText " Found known binary: iptables-save (firewall) - ${BINARY}" ;;
istat) ISTATBINARY="${BINARY}"; LogText " Found known binary: istat (file information) - ${BINARY}" ;;
journalctl) JOURNALCTLBINARY="${BINARY}"; LogText " Found known binary: journalctl (systemd journal) - ${BINARY}" ;;
kadmin.local) KADMINLOCALBINARY="${BINARY}"; LogText " Found known binary: kadmin.local (krb5) - ${BINARY}" ;;
kdb5_util) KDB5UTILBINARY="${BINARY}"; LogText " Found known binary: kdb5_util (krb5) - ${BINARY}" ;;
kldstat) KLDSTATBINARY="${BINARY}"; LogText " Found known binary: kldstat (kernel modules) - ${BINARY}" ;;
kstat) KSTATBINARY="${BINARY}"; LogText " Found known binary: kstat (kernel statistics) - ${BINARY}" ;;
launchctl) LAUNCHCTL_BINARY="${BINARY}"; SERVICE_MANAGER="launchd"; LogText " Found known binary: launchctl (launchd client) - ${BINARY}" ;;

188
include/tests_kerberos Normal file
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@ -0,0 +1,188 @@
#!/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 | ${TRBINARY:-tr} '\n' ' ')"
if [ -z "${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"
FOUND=0
if [ ${SKIPTEST} -eq 0 ]; then
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
fi
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
#
#################################################################################
#
# 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

2
lynis
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@ -1018,7 +1018,7 @@ ${NORMAL}
if [ "${TEST_GROUP_TO_CHECK}" = "all" ]; then
LogText "Info: perform tests from all categories"
INCLUDE_TESTS="boot_services kernel memory_processes authentication shells \
INCLUDE_TESTS="boot_services kernel memory_processes authentication kerberos shells \
filesystems usb storage storage_nfs nameservices dns ports_packages networking printers_spoolers \
mail_messaging firewalls webservers ssh snmp databases ldap php squid logging \
insecure_services banners scheduling accounting time crypto virtualization containers \