cis-ubuntu1804-v220-5-1-2-7

DevOps & Security

Ensure rsyslog is not configured to receive logs from a remote client

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Source SKILL.md: https://github.com/CyberStrikeus/CyberStrike/blob/HEAD/.cyberstrike/skill/CIS_benchmarks/Operating_Systems/Ubuntu/CIS_Ubuntu_Linux_18.04_LTS_Benchmark_v2.2.0/cis-ubuntu1804-v220-5-1-2-7/SKILL.md

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5.1.2.7 Ensure rsyslog is not configured to receive logs from a remote client (Automated)

Profile

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

Description

RSyslog supports the ability to receive messages from remote hosts, thus acting as a log server. Clients should not receive data from other hosts.

Rationale

If a client is configured to also receive data, thus turning it into a server, the client system is acting outside it's operational boundary.

Audit Procedure

Command Line

Review the /etc/rsyslog.conf and /etc/rsyslog.d/*.conf files and verify that the system is not configured to accept incoming logs.

Old format:

grep '$ModLoad imtcp' /etc/rsyslog.conf /etc/rsyslog.d/*.conf
grep '$InputTCPServerRun' /etc/rsyslog.conf /etc/rsyslog.d/*.conf

No output expected.

New format:

grep -P -- '^\h*module\(load="imtcp"\)' /etc/rsyslog.conf /etc/rsyslog.d/*.conf
grep -P -- '^\h*input\(type="imtcp" port="514"\)' /etc/rsyslog.conf /etc/rsyslog.d/*.conf

No output expected.

Expected Result

No output should be returned for any of the commands.

Remediation

Command Line

Remove or comment out any lines in /etc/rsyslog.conf and /etc/rsyslog.d/*.conf that configure rsyslog to accept incoming logs. Restart the service:

systemctl restart rsyslog

Default Value

rsyslog is not configured to receive logs from remote clients by default.

References

NIST SP 800-53 Rev. 5: AU-2, AU-12, CM-6, CM-7

CIS Controls

Controls Version	Control
v8	4.8 Uninstall or Disable Unnecessary Services on Enterprise Assets and Software - Uninstall or disable unnecessary services on enterprise assets and software.
v8	8.2 Collect Audit Logs - Collect audit logs. Ensure that logging, per the enterprise's audit log management process, has been enabled across enterprise assets.
v7	6.2 Activate audit logging - Ensure that local logging has been enabled on all systems and networking devices.
v7	6.3 Enable Detailed Logging - Enable system logging to include detailed information such as an event source, date, user, timestamp, source addresses, destination addresses, and other useful elements.
v7	9.2 Ensure Only Approved Ports, Protocols and Services Are Running - Ensure that only network ports, protocols, and services listening on a system with validated business needs, are running on each system.