Information
rsyslog will create logfiles that do not already exist on the system. This setting controls what permissions will be applied to these newly created files.
Rationale:
It is important to ensure that log files have the correct permissions to ensure that sensitive data is archived and protected.
Solution
Edit the /etc/rsyslog.conf and /etc/rsyslog.d/*.conf files and set every instance of $FileCreateMode to 0640 or more restrictive:
$FileCreateMode 0640