Cis Ubuntu1604 V200 4 2 1 5

CIS Ubuntu Linux 16.04 LTS Benchmark v2.0.0 - Control 4.2.1.5

Profile

• Level: 1 - Server
• Level: 1 - Workstation
• Assessment Status: Automated

Description

The rsyslog utility supports the ability to send logs it gathers to a remote log host running syslogd(8) or to receive messages from remote hosts, reducing administrative overhead.

Rationale

Storing log data on a remote host protects log integrity from local attacks. If an attacker gains root access on the local system, they could tamper with or remove log data that is stored on the local system.

Note: Ensure that the selection of logfiles being sent follows local site policy.

Impact

None.

Audit Procedure

Review the /etc/rsyslog.conf and /etc/rsyslog.d/*.conf files and verify that logs are sent to a central host.

Command Line

grep -E '^\s*([^#]+\s+)?action\(([^#]+\s+)?\btarget=\"?[^#"]+\"?\b' /etc/rsyslog.conf /etc/rsyslog.d/*.conf

Output should include target=<FQDN or IP of remote loghost>

OR

grep -E '^[^#]\s*\S+\.\*\s+@' /etc/rsyslog.conf /etc/rsyslog.d/*.conf

Expected Result

Output should include either the FQDN or the IP of the remote loghost.

Remediation

Edit the /etc/rsyslog.conf and /etc/rsyslog.d/*.conf files and add one of the following lines:

Command Line

Newer syntax:

# Add the following to /etc/rsyslog.conf or /etc/rsyslog.d/*.conf:
*.* action(type="omfwd" target="<FQDN or ip of loghost>" port="<port number>" protocol="tcp"
        action.resumeRetryCount="<number of re-tries>"
                                        queue.type="LinkedList"
        queue.size=<number of messages to queue>)

Example:

*.* action(type="omfwd" target="192.168.2.100" port="514" protocol="tcp"
        action.resumeRetryCount="100"
        queue.type="LinkedList" queue.size="1000")

Older syntax:

# Add the following to /etc/rsyslog.conf or /etc/rsyslog.d/*.conf:
*.* @@<FQDN or ip of loghost>

Example:

*.* @@192.168.2.100

Run the following command to reload the rsyslog configuration:

systemctl restart rsyslog

Additional Information

The double "at" sign (@@) directs rsyslog to use TCP to send log messages to the server, which is a more reliable transport mechanism than the default UDP protocol.

The *.* is a "wildcard" to send all logs to the remote loghost.

Default Value

rsyslog is not configured to send logs to a remote host by default.

References

1. See the rsyslog.conf(5) man page for more information.

CIS Controls