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1.193 RHEL-09-253065

Information

RHEL 9 must not send Internet Control Message Protocol (ICMP) redirects.

GROUP ID: V-257968
RULE ID: SV-257968r991589

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.

Solution

Configure RHEL 9 to not allow interfaces to perform IPv4 ICMP redirects.

Add or edit the following line in a single system configuration file, in the "/etc/sysctl.d/" directory:

net.ipv4.conf.all.send_redirects = 0

Load settings from all system configuration files with the following command:

$ sudo sysctl --system

See Also

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

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6b., CAT|II, CCI|CCI-000366, Rule-ID|SV-257968r991589_rule, STIG-ID|RHEL-09-253065, Vuln-ID|V-257968

Plugin: Unix

Control ID: 1bfbc1fb28cde3524db24f75f7baf1bc037a53f7324da9956497019f3e2112de