bump to 4.1.4

* allow multiple exception users for 99.5.2.4

* move clean up part of previous commit

* split clean up part of previous commit

* add tests for multiple allowed and denied ssh users

* fix script to correctly set multiple allowed and denied ssh users

* add cleanup resolved check to 5.2.18

* apply shellfmt to 5.2.18

---------

Co-authored-by: GoldenKiwi <thibault.dewailly@corp.ovh.com>

README.md

@@ -16,6 +16,9 @@
 Modular Debian 10/11/12 security hardening scripts based on [cisecurity.org](https://www.cisecurity.org)
 recommendations. We use it at [OVHcloud](https://www.ovhcloud.com) to harden our PCI-DSS infrastructure.
 
+NB : Although Debian 12 CIS Hardening guide is still in development, we do use this set of scripts
+in production at OVHcloud on Debian 12 Operating Systems.
+
 ```console
 $ bin/hardening.sh --audit-all
 [...]
@@ -40,12 +43,11 @@ hardening [INFO] Treating /opt/cis-hardening/bin/hardening/6.2.19_check_duplicat
 ```console
 $ git clone https://github.com/ovh/debian-cis.git && cd debian-cis
 $ cp debian/default /etc/default/cis-hardening
-$ sed -i "s#CIS_LIB_DIR=.*#CIS_LIB_DIR='$(pwd)'/lib#" etc/default/cis-hardening
-$ sed -i "s#CIS_CHECKS_DIR=.*#CIS_CHECKS_DIR='$(pwd)'/bin/hardening#" etc/default/cis-hardening
-$ sed -i "s#CIS_CONF_DIR=.*#CIS_CONF_DIR='$(pwd)'/etc#" etc/default/cis-hardening
-$ sed -i "s#CIS_TMP_DIR=.*#CIS_TMP_DIR='$(pwd)'/tmp#" etc/default/cis-hardening
-$ bin/hardening/1.1.1.1_disable_freevxfs.sh --audit-all
-hardening                 [INFO] Treating /opt/cis-hardening/bin/hardening/1.1.1.1_disable_freevxfs.sh
+$ sed -i "s#CIS_LIB_DIR=.*#CIS_LIB_DIR='$(pwd)'/lib#" /etc/default/cis-hardening
+$ sed -i "s#CIS_CHECKS_DIR=.*#CIS_CHECKS_DIR='$(pwd)'/bin/hardening#" /etc/default/cis-hardening
+$ sed -i "s#CIS_CONF_DIR=.*#CIS_CONF_DIR='$(pwd)'/etc#" /etc/default/cis-hardening
+$ sed -i "s#CIS_TMP_DIR=.*#CIS_TMP_DIR='$(pwd)'/tmp#" /etc/default/cis-hardening
+$ ./bin/hardening/1.1.1.1_disable_freevxfs.sh --audit
 1.1.1.1_disable_freevxfs  [INFO] Working on 1.1.1.1_disable_freevxfs
 1.1.1.1_disable_freevxfs  [INFO] [DESCRIPTION] Disable mounting of freevxfs filesystems.
 1.1.1.1_disable_freevxfs  [INFO] Checking Configuration
@@ -244,6 +246,20 @@ built a secure environment. While we use it at OVHcloud to harden our PCI-DSS co
 infrastructure, we can not guarantee that it will work for you. It will not
 magically secure any random host.
 
+A word about numbering, implementation and sustainability over time of this repository:
+This project is born with the Debian 7 distribution in 2016. Over time, CIS Benchmark PDF
+has evolved, changing it's numbering, deleting obsolete checks.
+In order to keep retro-compatiblity with the last maintained Debian, the numbering
+has not been changed along with the PDF, because the configuration scripts are named after it.
+Changing the numbering might break automation for admins using it for years, and handling
+this issue without breaking anything would require a huge refactoring.
+As a consequence, please do not worry about numbering, the checks are there,
+but the numbering accross PDFs might differ.
+Please also note that all the check inside CIS Benchmark PDF might not be implemented
+in this set of scripts.
+We did choose the most relevant to us at OVHcloud, do not hesitate to make a
+Pull Request in order to add the missing script you might find relevant for you.
+
 Additionally, quoting the License:
 
 > THIS SOFTWARE IS PROVIDED BY OVH SAS AND CONTRIBUTORS ``AS IS'' AND ANY
@@ -257,6 +273,7 @@ Additionally, quoting the License:
 > (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 > SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+
 ## :satellite: Reference
 
 - **Center for Internet Security**: https://www.cisecurity.org/

bin/hardening.sh

@@ -299,7 +299,7 @@ for SCRIPT in $(find "${CIS_CHECKS_DIR}"/ -name "*.sh" | sort -V); do
         SCRIPT_PREFIX=$(grep -Eo '^[0-9.]+' <<<"$(basename "$SCRIPT")")
         # shellcheck disable=SC2001
         SCRIPT_PREFIX_RE=$(sed -e 's/\./\\./g' <<<"$SCRIPT_PREFIX")
-        if ! grep -qwE "(^| )$SCRIPT_PREFIX_RE" <<<"${TEST_LIST[@]}"; then
+        if ! grep -qE "(^|[[:space:]])$SCRIPT_PREFIX_RE([[:space:]]|$)" <<<"${TEST_LIST[@]}"; then
             # not in the list
             continue
         fi

bin/hardening/4.2.1.5_syslog-ng_remote_host.sh

@@ -16,10 +16,9 @@ set -u # One variable unset, it's over
 HARDENING_LEVEL=3
 # shellcheck disable=2034
 DESCRIPTION="Configure syslog-ng to send logs to a remote log host."
-
 PACKAGE='syslog-ng'
-
-PATTERN='destination[[:alnum:][:space:]*{]+(tcp|udp)[[:space:]]*\(\"[[:alnum:].]+\".'
+SYSLOG_BASEDIR='/etc/syslog-ng'
+PATTERN='destination[[:alnum:][:space:]*_*{]+(tcp|network|udp)[[:space:]]*\([[:space:]]*\"?[[:alnum:]\-.]+\"?.'
 
 # This function will be called if the script status is on enabled / audit mode
 audit() {

bin/hardening/4.2.1.6_remote_syslog-ng_acl.sh

@@ -18,9 +18,9 @@ HARDENING_LEVEL=3
 DESCRIPTION="Configure syslog to accept remote syslog messages only on designated log hosts."
 
 PACKAGE='syslog-ng'
-
+SYSLOG_BASEDIR='/etc/syslog-ng'
 REMOTE_HOST=""
-PATTERN='source[[:alnum:][:space:]*{]+(tcp|udp)[[:space:]]*\(\"[[:alnum:].]+\".'
+PATTERN='source[[:alnum:][:space:]*_*{]+(tcp|network|udp)[[:space:]]*\([[:space:]]*\"?[[:alnum:]\-.]+\"?.'
 
 # This function will be called if the script status is on enabled / audit mode
 audit() {
@@ -37,7 +37,7 @@ audit() {
             fi
         done
 
-        if [[ "$REMOTE_HOST" ]]; then
+        if [[ "$REMOTE_HOST" ]] && [[ "$REMOTE_HOST" != 'false' ]]; then
             info "This is the remote host, checking that it only accepts logs from specified zone"
             if [ "$FOUND" = 1 ]; then
                 ok "$PATTERN is present in $FILES"
@@ -70,7 +70,7 @@ apply() {
             fi
         done
 
-        if [[ "$REMOTE_HOST" ]]; then
+        if [[ "$REMOTE_HOST" ]] && [[ "$REMOTE_HOST" != 'false' ]]; then
             info "This is the remote host, checking that it only accepts logs from specified zone"
             if [ "$FOUND" = 1 ]; then
                 ok "$PATTERN is present in $FILES"

bin/hardening/5.2.18_sshd_limit_access.sh

@@ -22,13 +22,13 @@ FILE='/etc/ssh/sshd_config'
 
 # This function will be called if the script status is on enabled / audit mode
 audit() {
-    OPTIONS="AllowUsers='$ALLOWED_USERS' AllowGroups='$ALLOWED_GROUPS' DenyUsers='$DENIED_USERS' DenyGroups='$DENIED_GROUPS'"
+    OPTIONS=("AllowUsers='$ALLOWED_USERS'" "AllowGroups='$ALLOWED_GROUPS'" "DenyUsers='$DENIED_USERS'" "DenyGroups='$DENIED_GROUPS'")
     is_pkg_installed "$PACKAGE"
     if [ "$FNRET" != 0 ]; then
         ok "$PACKAGE is not installed!"
     else
         ok "$PACKAGE is installed"
-        for SSH_OPTION in $OPTIONS; do
+        for SSH_OPTION in "${OPTIONS[@]}"; do
             SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
             SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
             # shellcheck disable=SC2001
@@ -53,7 +53,7 @@ apply() {
         crit "$PACKAGE is absent, installing it"
         apt_install "$PACKAGE"
     fi
-    for SSH_OPTION in $OPTIONS; do
+    for SSH_OPTION in "${OPTIONS[@]}"; do
         SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
         SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
         # shellcheck disable=SC2001

bin/hardening/99.5.2.4_ssh_keys_from.sh

@@ -26,7 +26,7 @@ AUTHKEYFILE_PATTERN_DEFAULT=".ssh/authorized_keys .ssh/authorized_keys2"
 
 ALLOWED_IPS=""
 USERS_TO_CHECK=""
-EXCEPTION_USER=""
+EXCEPTION_USERS=""
 
 ALLOWED_NOLOGIN_SHELLS="/bin/false /usr/sbin/nologin"
 
@@ -137,7 +137,10 @@ audit() {
             continue
         else
             info "User $user has a valid shell ($shell)."
-            if [ "$user" = "root" ] && [ "$user" != "$EXCEPTION_USER" ]; then
+            if grep -qw "$user" <<<"$EXCEPTION_USERS"; then
+                info "User $user is named in EXEPTION_USERS and is thus skipped from check."
+                continue
+            elif [ "$user" = "root" ]; then
                 check_dir /root
                 continue
             elif $SUDO_CMD [ ! -d /home/"$user" ]; then
@@ -164,7 +167,7 @@ status=audit
 # Put authorized IPs you want to allow in "from" field of authorized_keys
 ALLOWED_IPS=""
 USERS_TO_CHECK=""
-EXCEPTION_USER=""
+EXCEPTION_USERS=""
 EOF
 }
 

debian/changelog

@@ -1,3 +1,14 @@
+cis-hardening (4.1-4) unstable; urgency=medium
+
+  * allow multiple users in 5.2.18 (#228)
+  * Allow multiple exception users to be defined for 99.5.2.4_ssh_keys_from (#221)
+  * Syslog-ng fixes and enhancements (#226)
+  * fix: Allow --only option to be called multiple times (#225)
+  * fix: update Readme to clarify project usage (#223)
+  * fix: typo in README. Update example of --audit usage (#222)
+
+ -- Thibault Dewailly <thibault.dewailly@ovhcloud.com>  Thu, 18 Jan 2024 09:13:15 +0000
+
 cis-hardening (4.1-3) unstable; urgency=medium
 
   * Adapt all scripts to yescrypt (#216)

tests/hardening/4.2.1.5_syslog-ng_remote_host.sh

@@ -38,6 +38,6 @@ EOF
     run subfile "${CIS_CHECKS_DIR}/${script}.sh" --audit-all
 
     # Cleanup
-    rm /etc/syslog-ng/conf.d/1_tcp_destination
+    rm -f /etc/syslog-ng/conf.d/1_tcp_destination
 
 }

tests/hardening/4.2.1.6_remote_syslog-ng_acl.sh

@@ -2,10 +2,37 @@
 # run-shellcheck
 test_audit() {
     describe Running on blank host
-    register_test retvalshouldbe 0
-    dismiss_count_for_test
+    register_test retvalshouldbe 1
     # shellcheck disable=2154
+    echo 'REMOTE_HOST="true"' >>"${CIS_CONF_DIR}/conf.d/${script}.cfg"
     run blank "${CIS_CHECKS_DIR}/${script}.sh" --audit-all
 
-    # TODO fill comprehensive tests
+    cp -a /etc/syslog-ng/syslog-ng.conf /tmp/syslog-ng.conf.bak
+    echo "source mySyslog tcp (\"127.0.0.1\")" >>/etc/syslog-ng/syslog-ng.conf
+
+    describe Checking one line conf
+    register_test retvalshouldbe 0
+    run oneline "${CIS_CHECKS_DIR}/${script}.sh" --audit-all
+
+    cp -a /tmp/syslog-ng.conf.bak /etc/syslog-ng/syslog-ng.conf
+    cat >>/etc/syslog-ng/syslog-ng.conf <<EOF
+    source mySyslog {
+    tcp ("127.0.0.1"),
+    port(1234),
+EOF
+
+    describe Checking mutliline conf
+    register_test retvalshouldbe 0
+    run multiline "${CIS_CHECKS_DIR}/${script}.sh" --audit-all
+
+    mv /tmp/syslog-ng.conf.bak /etc/syslog-ng/syslog-ng.conf
+    echo "source mySyslog tcp (\"127.0.0.1\")" >>/etc/syslog-ng/conf.d/1_tcp_source
+    cat /etc/syslog-ng/conf.d/1_tcp_source
+
+    describe Checking file in subdirectory
+    register_test retvalshouldbe 0
+    run subfile "${CIS_CHECKS_DIR}/${script}.sh" --audit-all
+
+    rm -f /etc/syslog-ng/conf.d/1_tcp_source
+
 }

tests/hardening/5.2.18_sshd_limit_access.sh

@@ -22,4 +22,109 @@ test_audit() {
     register_test contain "^DenyUsers[[:space:]]*nobody is present in /etc/ssh/sshd_config"
     register_test contain "^DenyGroups[[:space:]]*nobody is present in /etc/ssh/sshd_config"
     run resolved "${CIS_CHECKS_DIR}/${script}.sh" --audit-all
+
+    describe Check and report mismatch for allowed user
+    useradd -s /bin/bash johnallow
+    sed -i "s/ALLOWED_USERS=''/ALLOWED_USERS='johnallow'/" "${CIS_CONF_DIR}/conf.d/${script}.cfg"
+    register_test retvalshouldbe 1
+    register_test contain "^AllowUsers[[:space:]]*johnallow is not present in /etc/ssh/sshd_config"
+    register_test contain "^AllowGroups[[:space:]]** is present in /etc/ssh/sshd_config"
+    register_test contain "^DenyUsers[[:space:]]*nobody is present in /etc/ssh/sshd_config"
+    register_test contain "^DenyGroups[[:space:]]*nobody is present in /etc/ssh/sshd_config"
+    run allowed_user_mismatch "${CIS_CHECKS_DIR}/${script}.sh" --audit-all
+
+    describe Correctly apply allowed user
+    # the previous test checked that ALLOWED_USERS is set but not correctly applied in sshd_config so we apply it now
+    "${CIS_CHECKS_DIR}/${script}.sh" || true
+    # and check again that the fix was correctly applied
+    register_test retvalshouldbe 0
+    register_test contain "^AllowUsers[[:space:]]*johnallow is present in /etc/ssh/sshd_config"
+    register_test contain "^AllowGroups[[:space:]]** is present in /etc/ssh/sshd_config"
+    register_test contain "^DenyUsers[[:space:]]*nobody is present in /etc/ssh/sshd_config"
+    register_test contain "^DenyGroups[[:space:]]*nobody is present in /etc/ssh/sshd_config"
+    run fix_user_mismatch "${CIS_CHECKS_DIR}/${script}.sh" --apply-all
+
+    describe Check and report mismatch for multiple allowed users
+    useradd -s /bin/bash janeallow
+    sed -i "s/johnallow/johnallow janeallow/" "${CIS_CONF_DIR}/conf.d/${script}.cfg"
+    register_test retvalshouldbe 1
+    register_test contain "^AllowUsers[[:space:]]*johnallow janeallow is not present in /etc/ssh/sshd_config"
+    register_test contain "^AllowGroups[[:space:]]** is present in /etc/ssh/sshd_config"
+    register_test contain "^DenyUsers[[:space:]]*nobody is present in /etc/ssh/sshd_config"
+    register_test contain "^DenyGroups[[:space:]]*nobody is present in /etc/ssh/sshd_config"
+    run multi_allowed_user_mismatch "${CIS_CHECKS_DIR}/${script}.sh" --audit-all
+
+    describe Correctly apply multiple allowed users
+    # the previous test checked that ALLOWED_USERS is set but not correctly applied in sshd_config so we apply it now
+    "${CIS_CHECKS_DIR}/${script}.sh" || true
+    # and check again that the fix was correctly applied
+    tail -n 5 /etc/ssh/sshd_config
+    register_test retvalshouldbe 0
+    register_test contain "^AllowUsers[[:space:]]*johnallow janeallow is present in /etc/ssh/sshd_config"
+    register_test contain "^AllowGroups[[:space:]]** is present in /etc/ssh/sshd_config"
+    register_test contain "^DenyUsers[[:space:]]*nobody is present in /etc/ssh/sshd_config"
+    register_test contain "^DenyGroups[[:space:]]*nobody is present in /etc/ssh/sshd_config"
+    run fix_multi_allowed_user_mismatch "${CIS_CHECKS_DIR}/${script}.sh" --audit-all
+
+    # reset allowed users to default before continuing
+    sed -i "s/ALLOWED_USERS='johnallow janeallow'/ALLOWED_USERS=''/" "${CIS_CONF_DIR}/conf.d/${script}.cfg"
+
+    describe Check and report mismatch for denied user
+    useradd -s /bin/bash peterdeny
+    sed -i "s/DENIED_USERS=''/DENIED_USERS='peterdeny'/" "${CIS_CONF_DIR}/conf.d/${script}.cfg"
+    register_test retvalshouldbe 1
+    register_test contain "^AllowUsers[[:space:]]** is present in /etc/ssh/sshd_config"
+    register_test contain "^AllowGroups[[:space:]]** is present in /etc/ssh/sshd_config"
+    register_test contain "^DenyUsers[[:space:]]*peterdeny is not present in /etc/ssh/sshd_config"
+    register_test contain "^DenyGroups[[:space:]]*nobody is present in /etc/ssh/sshd_config"
+    run denied_user_mismatch "${CIS_CHECKS_DIR}/${script}.sh" --audit-all
+
+    describe Correctly apply denied user
+    # the previous test checked that DENIED_USERS is set but not correctly applied in sshd_config so we apply it now
+    "${CIS_CHECKS_DIR}/${script}.sh" || true
+    # and check again that the fix was correctly applied
+    register_test retvalshouldbe 0
+    register_test contain "^AllowUsers[[:space:]]** is present in /etc/ssh/sshd_config"
+    register_test contain "^AllowGroups[[:space:]]** is present in /etc/ssh/sshd_config"
+    register_test contain "^DenyUsers[[:space:]]*peterdeny is present in /etc/ssh/sshd_config"
+    register_test contain "^DenyGroups[[:space:]]*nobody is present in /etc/ssh/sshd_config"
+    run fix_denied_user_mismatch "${CIS_CHECKS_DIR}/${script}.sh" --apply-all
+
+    describe Check and report mismatch for multiple denied users
+    useradd -s /bin/bash marrydeny
+    sed -i "s/peterdeny/peterdeny marrydeny/" "${CIS_CONF_DIR}/conf.d/${script}.cfg"
+    register_test retvalshouldbe 1
+    register_test contain "^AllowUsers[[:space:]]** is present in /etc/ssh/sshd_config"
+    register_test contain "^AllowGroups[[:space:]]** is present in /etc/ssh/sshd_config"
+    register_test contain "^DenyUsers[[:space:]]*peterdeny marrydeny is not present in /etc/ssh/sshd_config"
+    register_test contain "^DenyGroups[[:space:]]*nobody is present in /etc/ssh/sshd_config"
+    run multi_denied_user_mismatch "${CIS_CHECKS_DIR}/${script}.sh" --audit-all
+
+    describe Correctly apply multiple denied users
+    # the previous test checked that DENIED_USERS is set but not correctly applied in sshd_config so we apply it now
+    "${CIS_CHECKS_DIR}/${script}.sh" || true
+    # and check again that the fix was correctly applied
+    register_test retvalshouldbe 0
+    register_test contain "^AllowUsers[[:space:]]** is present in /etc/ssh/sshd_config"
+    register_test contain "^AllowGroups[[:space:]]** is present in /etc/ssh/sshd_config"
+    register_test contain "^DenyUsers[[:space:]]*peterdeny marrydeny is present in /etc/ssh/sshd_config"
+    register_test contain "^DenyGroups[[:space:]]*nobody is present in /etc/ssh/sshd_config"
+    run fix_multi_denied_user_mismatch "${CIS_CHECKS_DIR}/${script}.sh" --audit-all
+
+    # reset to prevent other test from possibly failing in the future
+    sed -i "s/DENIED_USERS='peterdeny marrydeny'/DENIED_USERS=''/" "${CIS_CONF_DIR}/conf.d/${script}.cfg"
+    "${CIS_CHECKS_DIR}/${script}.sh" || true
+    describe Checking resolved state
+    register_test retvalshouldbe 0
+    register_test contain "^AllowUsers[[:space:]]** is present in /etc/ssh/sshd_config"
+    register_test contain "^AllowGroups[[:space:]]** is present in /etc/ssh/sshd_config"
+    register_test contain "^DenyUsers[[:space:]]*nobody is present in /etc/ssh/sshd_config"
+    register_test contain "^DenyGroups[[:space:]]*nobody is present in /etc/ssh/sshd_config"
+    run cleanup_resolved "${CIS_CHECKS_DIR}/${script}.sh" --audit-all
+
+    # Cleanup
+    userdel johnallow
+    userdel janeallow
+    userdel peterdeny
+    userdel marrydeny
 }

tests/hardening/99.5.2.4_ssh_keys_from.sh

@@ -2,7 +2,7 @@
 # run-shellcheck
 test_audit() {
     # shellcheck disable=2154
-    echo 'EXCEPTION_USER="root"' >>"${CIS_CONF_DIR}/conf.d/${script}.cfg"
+    echo 'EXCEPTION_USERS=""' >>"${CIS_CONF_DIR}/conf.d/${script}.cfg"
 
     skip_tests
     # shellcheck disable=2154
@@ -12,12 +12,29 @@ test_audit() {
     describe Running on blank host
     register_test retvalshouldbe 0
     dismiss_count_for_test
+    register_test contain "[INFO] User root has a valid shell"
     register_test contain "[WARN] secaudit has a valid shell but no authorized_keys file"
     register_test contain "[INFO] User jeantestuser has a valid shell"
     register_test contain "[INFO] User jeantestuser has no home directory"
     # shellcheck disable=2154
     run blank "${CIS_CHECKS_DIR}/${script}.sh" --audit-all
 
+    mkdir -p /root/.ssh
+    ssh-keygen -N "" -t ed25519 -f /tmp/rootkey1
+    cat /tmp/rootkey1.pub >>/root/.ssh/authorized_keys
+    describe Check /root is used for root user instead of home by placing key without from field
+    register_test retvalshouldbe 1
+    run rootcheck "${CIS_CHECKS_DIR}/${script}.sh" --audit-all
+
+    echo 'EXCEPTION_USERS="root exceptiontestuser"' >>"${CIS_CONF_DIR}/conf.d/${script}.cfg"
+    useradd -s /bin/bash exceptiontestuser
+    describe Check multiple exception users are skipped
+    register_test retvalshouldbe 0
+    register_test contain "[INFO] User root is named in EXEPTION_USERS and is thus skipped from check."
+    register_test contain "[INFO] User exceptiontestuser is named in EXEPTION_USERS and is thus skipped from check."
+    # shellcheck disable=2154
+    run exceptionusers "${CIS_CHECKS_DIR}/${script}.sh" --audit-all
+
     mkdir -p /home/secaudit/.ssh
     touch /home/secaudit/.ssh/authorized_keys2
     describe empty authorized keys file
@@ -74,7 +91,9 @@ test_audit() {
     run checkuser "${CIS_CHECKS_DIR}/${script}.sh" --audit-all
 
     # Cleanup
+    userdel exceptiontestuser
     userdel jeantestuser
     userdel -r jeantest2
-    rm -f /tmp/key1 /tmp/key1.pub
+    rm -f /tmp/key1 /tmp/key1.pub /tmp/rootkey1.pub
+    rm -rf /root/.ssh
 }