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V-282695

CAT II (Medium)

TOSS 5 must not send Internet Control Message Protocol (ICMP) redirects.

Rule ID

SV-282695r1201065_rule

STIG

Tri-Lab Operating System Stack (TOSS) 5 Security Technical Implementation Guide

Version

V1R1

CCIs

CCI-000366

Discussion

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.

Check Content

Verify TOSS 5 does not IPv4 ICMP redirect messages using the following command:

$ sudo sysctl net.ipv4.conf.all.send_redirects

net.ipv4.conf.all.send_redirects = 0

If the returned line does not have a value of "0", or a line is not returned, this is a finding.

Fix Text

Configure TOSS 5 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 using the following command:

$ sudo sysctl --system