Vulnerability Discussion

OpenShift and its components must generate audit records when modifying security objects. All the components must use the same standard so that the events can be tied together to understand what took place within the overall container platform. This must establish, correlate, and help assist with investigating the events relating to an incident, or identify those responsible.

Without audit record generation, unauthorized users can modify security objects unknowingly for malicious intent creating vulnerabilities within the container platform.

Satisfies: SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250

Check

Verify the Red Hat Enterprise Linux CoreOS (RHCOS) is configured to generate audit records when successful/unsuccessful attempts to modify security categories or objects occur 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" -e "key=perm_mod" /etc/audit/audit.rules' 2>/dev/null; done

Confirm the following rules exist on each node:

-a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F path=/usr/bin/chcon -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -F path=/usr/sbin/restorecon -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -F path=/usr/sbin/semanage -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -F path=/usr/sbin/setfiles -F auid>=1000 -F auid!=unset -F key=privileged
-a always,exit -F path=/usr/sbin/setsebool -F auid>=1000 -F auid!=unset -F key=privileged

If the above rules are not listed on each node, this is a finding.

Fix

Apply the machine config to configure modification audit records by executing the following:

for mcpool in $(oc get mcp -oname | sed "s:.*/::" ); do
echo "apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:
name: 75-modify-categories-secobjects-rules-$mcpool
labels:
machineconfiguration.openshift.io/role: $mcpool
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20fremovexattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20fremovexattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
mode: 0644
path: /etc/audit/rules.d/75-fremovexattr_dac_modification.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20fsetxattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20fsetxattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
mode: 0644
path: /etc/audit/rules.d/75-fsetxattr_dac_modification.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20lremovexattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20lremovexattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
mode: 0644
path: /etc/audit/rules.d/75-lremovexattr_dac_modification.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20lsetxattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20lsetxattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
mode: 0644
path: /etc/audit/rules.d/75-lsetxattr_dac_modification.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20removexattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20removexattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
mode: 0644
path: /etc/audit/rules.d/75-removexattr_dac_modification.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/chcon%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_chcon_execution.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/sbin/restorecon%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_restorecon_execution.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/sbin/semanage%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_semanage_execution.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/sbin/setfiles%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_setfiles_execution.rules
overwrite: true
- contents:
source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/sbin/setsebool%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_setsebool_execution.rules
overwrite: true
" | oc apply -f -
done