The Red Hat Enterprise Linux CoreOS (RHCOS) chrony Daemon must use multiple NTP servers to generate audit record time stamps.

An XCCDF Rule

Description

<VulnDiscussion>Utilizing multiple NTP servers for the chrony daemon in RHCOS ensures accurate and reliable audit record timestamps. It improves time synchronization, mitigates time drift, provides redundancy, and enhances resilience against attacks. Knowing when a sequence of events for an incident occurred is crucial to understand what may have taken place. Without a common clock, the components generating audit events could be out of synchronization and would then present a picture of the event that is warped and corrupted. To give a clear picture, it is important that the container platform and its components use a common internal clock.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>

ID: SV-257526r921521_rule
Severity: Medium
References: CCI-000159
Updated: 9 months ago

Apply the machine config by executing the following, replacing the variables in the MachineConfig with organizationally-defined NTP servers.

for mcpool in $(oc get mcp -oname | sed ""s:.*/::"" ); do
echo "apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:  name: 90-chrony-ntp-servers-set-$mcpool
  labels:
    machineconfiguration.openshift.io/role: $mcpool
spec:
  config:
    ignition:
      version: 3.1.0
      storage:
        files:
        - contents:
            source: data:,%23%20Allow%20for%20extra%20configuration%20files.%20This%20is%20useful%0A%23%20for%20admins%20specifying%20their%20own%20NTP%20servers%0Ainclude%20%2Fetc%2Fchrony.d%2F%2A.conf%0A%0A%23%20Set%20chronyd%20as%20client-only.%0Aport%200%0A%0A%23%20Disable%20chronyc%20from%20the%20network%0Acmdport%200%0A%0A%23%20Record%20the%20rate%20at%20which%20the%20system%20clock%20gains%2Flosses%20time.%0Adriftfile%20%2Fvar%2Flib%2Fchrony%2Fdrift%0A%0A%23%20Allow%20the%20system%20clock%20to%20be%20stepped%20in%20the%20first%20three%20updates%0A%23%20if%20its%20offset%20is%20larger%20than%201%20second.%0Amakestep%201.0%203%0A%0A%23%20Enable%20kernel%20synchronization%20of%20the%20real-time%20clock%20%28RTC%29.%0Artcsync%0A%0A%23%20Enable%20hardware%20timestamping%20on%20all%20interfaces%20that%20support%20it.%0A%23hwtimestamp%20%2A%0A%0A%23%20Increase%20the%20minimum%20number%20of%20selectable%20sources%20required%20to%20adjust%0A%23%20the%20system%20clock.%0A%23minsources%202%0A%0A%23%20Allow%20NTP%20client%20access%20from%20local%20network.%0A%23allow%20192.168.0.0%2F16%0A%0A%23%20Serve%20time%20even%20if%20not%20synchronized%20to%20a%20time%20source.%0A%23local%20stratum%2010%0A%0A%23%20Require%20authentication%20%28nts%20or%20key%20option%29%20for%20all%20NTP%20sources.%0A%23authselectmode%20require%0A%0A%23%20Specify%20file%20containing%20keys%20for%20NTP%20authentication.%0Akeyfile%20%2Fetc%2Fchrony.keys%0A%0A%23%20Insert%2Fdelete%20leap%20seconds%20by%20slewing%20instead%20of%20stepping.%0A%23leapsecmode%20slew%0A%0A%23%20Get%20TAI-UTC%20offset%20and%20leap%20seconds%20from%20the%20system%20tz%20database.%0Aleapsectz%20right%2FUTC%0A%0A%23%20Specify%20directory%20for%20log%20files.%0Alogdir%20%2Fvar%2Flog%2Fchrony%0A%0A%23%20Select%20which%20information%20is%20logged.%0A%23log%20measurements%20statistics%20tracking
            mode: 420
            overwrite: true
            path: /etc/chrony.conf
        - contents:
            source: data:,
          mode: 420
          overwrite: true
          path: /etc/chrony.d/.mco-keep
        - contents:
             source: data:,%23%0A%23%20This%20file%20controls%20the%20configuration%20of%20the%20ntp%20server%0A%23%200.pool.ntp.org%2C1.pool.ntp.org%2C2.pool.ntp.org%2C3.pool.ntp.org%20we%20have%20to%20put%20variable%20array%20name%20here%20for%20mutilines%20remediation%20%0A%0Aserver%20<SERVER1.EXAMPLE.COM>%20minpoll%204%20maxpoll%2010%0Aserver%20<SERVER2.EXAMPLE.COM>%20minpoll%204%20maxpoll%2010%0Aserver%20<SERVER3.EXAMPLE.COM>%20minpoll%204%20maxpoll%2010%0Aserver%20<SERVER4.EXAMPLE.COM>%20minpoll%204%20maxpoll%2010%0A
          mode: 420
          overwrite: true
          path: /etc/chrony.d/ntp-server.conf
" | oc apply -f -
done

The Red Hat Enterprise Linux CoreOS (RHCOS) chrony Daemon must use multiple NTP servers to generate audit record time stamps.

Description

Remediation - Manual Procedure