1.360 RHEL-09-652025

Information

RHEL 9 must be configured so that the rsyslog daemon does not accept log messages from other servers unless the server is being used for log aggregation.

GROUP ID: V-258143
RULE ID: SV-258143r1045283

Unintentionally running a rsyslog server accepting remote messages puts the system at increased risk. Malicious rsyslog messages sent to the server could exploit vulnerabilities in the server software itself, could introduce misleading information into the system's logs, or could fill the system's storage leading to a denial of service.

If the system is intended to be a log aggregation server, its use must be documented with the information system security officer (ISSO).

Solution

Configure RHEL 9 to not receive remote logs using rsyslog.

Remove the lines in /etc/rsyslog.conf and any files in the /etc/rsyslog.d directory that match any of the following:

module(load="imtcp")
module(load="imudp")
module(load="imrelp")
input(type="imudp" port="514")
input(type="imtcp" port="514")
input(type="imrelp" port="514")

The rsyslog daemon must be restarted for the changes to take effect:

$ sudo systemctl restart rsyslog.service

See Also

https://workbench.cisecurity.org/benchmarks/22008