Open Shift must automatically audit account removal actions.

STIG ID: CNTR-OS-000080  |  SRG: SRG-APP-000029-CTR-000085 |  Severity: medium |  CCI: CCI-001405 |  Vulnerability Id: V-257512 | 

Vulnerability Discussion

When application accounts are removed, user accessibility is affected. Once an attacker establishes access to an application, the attacker often attempts to remove authorized accounts to disrupt services or prevent the implementation of countermeasures. Auditing account removal actions provides logging that can be used for forensic purposes.

To address access requirements, many application developers choose to integrate their applications with enterprise-level authentication/access/audit mechanisms meeting or exceeding access control policy requirements. Such integration allows the application developer to off-load those access control functions and focus on core application features and functionality.

Check

Verify the audit rules capture the execution of setuid and setgid binaries by executing the following:

for node in $(oc get node -oname); do oc debug $node -- chroot /host /bin/bash -c 'echo -n "$HOSTNAME "; grep -e key=privileged /etc/audit/audit.rules || echo "not found"' 2>/dev/null; done

If "not found" is printed, this is a finding.

Confirm the following rules exist on each node:

-a always,exit -S all -F path=/usr/libexec/dbus-1/dbus-daemon-launch-helper -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/sbin/grub2-set-bootflag -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/libexec/openssh/ssh-keysign -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/bin/chage -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/bin/fusermount3 -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/bin/fusermount -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/bin/gpasswd -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/bin/mount -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/bin/newgrp -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/bin/passwd -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/bin/pkexec -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/bin/sudo -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/bin/su -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/bin/umount -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/bin/write -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/libexec/sssd/krb5_child -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/libexec/sssd/ldap_child -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/libexec/sssd/proxy_child -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/libexec/sssd/selinux_child -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/libexec/utempter -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/lib/polkit-1/polkit-agent-helper-1 -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/sbin/mount.nfs -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/sbin/pam_timestamp_check -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -S all -F path=/usr/sbin/unix_chkpwd -F auid>=1000 -F auid!=unset -F key=privileged

To find all setuid binaries on the system, execute the following:

for node in $(oc get node -oname); do oc debug $node -- chroot /host /bin/bash -c 'echo -n "$HOSTNAME "; find / -xdev -type f -perm -4000 -o -type f -perm -2000 2>/dev/null'; done

If any setuid binary does not have a corresponding audit rule, this is a finding.

Fix

Apply the machine config by executing the following:

for mcpool in $(oc get mcp -oname | sed "s:.*/::" ); do
echo "apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:
name: 75-setuid-setgid-binaries-$mcpool
labels:
machineconfiguration.openshift.io/role: $mcpool
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/chage%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
mode: 0644
path: /etc/audit/rules.d/75-usr_bin_chage_execution.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/fusermount%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
mode: 0644
path: /etc/audit/rules.d/75-usr_bin_fusermount_execution.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/fusermount3%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
mode: 0644
path: /etc/audit/rules.d/75-usr_bin_fusermount3_execution.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/gpasswd%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
mode: 0644
path: /etc/audit/rules.d/75-usr_bin_gpasswd_execution.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/mount%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
mode: 0644
path: /etc/audit/rules.d/75-usr_bin_mount_execution.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/newgrp%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
mode: 0644
path: /etc/audit/rules.d/75-usr_bin_newgrp_execution.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/passwd%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
mode: 0644
path: /etc/audit/rules.d/75-usr_bin_passwd_execution.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/pkexec%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
mode: 0644
path: /etc/audit/rules.d/75-usr_bin_pkexec_execution.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/su%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
mode: 0644
path: /etc/audit/rules.d/75-usr_bin_su_execution.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/sudo%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
mode: 0644
path: /etc/audit/rules.d/75-usr_bin_sudo_execution.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/umount%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
mode: 0644
path: /etc/audit/rules.d/75-usr_bin_umount_execution.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/lib/polkit-1/polkit-agent-helper-1%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
mode: 0644
path: /etc/audit/rules.d/75-usr_lib_polkit_helper_execution.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/libexec/dbus-1/dbus-daemon-launch-helper%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
mode: 0644
path: /etc/audit/rules.d/75-dbus_daemon_launch_helper.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/libexec/sssd/krb5_child%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
mode: 0644
path: /etc/audit/rules.d/75-usr_libexec_sssd_krb5_child.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/libexec/sssd/ldap_child%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
mode: 0644
path: /etc/audit/rules.d/75-usr_libexec_sssd_ldap_child.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/libexec/sssd/proxy_child%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
mode: 0644
path: /etc/audit/rules.d/75-usr_libexec_sssd_proxy_child.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/libexec/sssd/selinux_child%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
mode: 0644
path: /etc/audit/rules.d/75-usr_libexec_sssd_selinux_child.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/sbin/grub2-set-bootflag%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
mode: 0644
path: /etc/audit/rules.d/75-grub2_set_bootflag.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/sbin/mount.nfs%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
mode: 0644
path: /etc/audit/rules.d/75-usr_sbin_mount_nfs.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/sbin/pam_timestamp_check%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
mode: 0644
path: /etc/audit/rules.d/75-usr_sbin_pam_timestamp_check.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/sbin/unix_chkpwd%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
mode: 0644
path: /etc/audit/rules.d/75-usr_sbin_unix_chkpwd.rules
overwrite: true
" | oc apply -f -
done
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