SLEM 5 must not send Internet Protocol version 4 (IPv4) 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.
- ID
- SV-261317r996421_rule
- Version
- SLEM-05-253030
- Severity
- Medium
- References
- Updated
Remediation Templates
A Manual Procedure
Configure SLEM 5 to not allow interfaces to perform IPv4 ICMP redirects by running the following command as an administrator:
> sudo sysctl -w net.ipv4.conf.all.send_redirects=0
If "0" is not the system's default value, add or update the following line in "/etc/sysctl.d/99-stig.conf":