AlmaLinux OS 9 must not send Internet Control Message Protocol (ICMP) redirects.
An XCCDF Rule
Description
ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages contain information from the system's route table possibly revealing portions of the network topology. The ability to send ICMP redirects is only appropriate for systems acting as routers.
- ID
- SV-269256r1050138_rule
- Version
- ALMA-09-019930
- Severity
- Medium
- References
- Updated
Remediation Templates
A Manual Procedure
Configure AlmaLinux OS 9 to not allow interfaces to perform ICMP redirects.
Create a numbered *.conf file in /etc/sysctl.d/ with the following content:
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0