The Photon operating system must prevent IPv4 Internet Control Message Protocol (ICMP) redirect messages from being accepted.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-258888	PHTN-40-000225	SV-258888r933725_rule		Medium

Description
ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack.

STIG	Date
VMware vSphere 8.0 vCenter Appliance Photon OS 4.0 Security Technical Implementation Guide	2023-10-29

Details

Check Text ( C-62628r933723_chk )
At the command line, run the following command to verify ICMP redirects are not accepted: # /sbin/sysctl -a --pattern "net.ipv4.conf.(all|default).accept_redirects" Expected result: net.ipv4.conf.all.accept_redirects = 0 net.ipv4.conf.default.accept_redirects = 0 If the "accept_redirects" kernel parameters are not set to "0", this is a finding.

Fix Text (F-62537r933724_fix)
Navigate to and open: /etc/sysctl.d/zz-stig-hardening.conf Add or update the following lines: net.ipv4.conf.all.accept_redirects = 0 net.ipv4.conf.default.accept_redirects = 0 At the command line, run the following command to load the new configuration: # /sbin/sysctl --load /etc/sysctl.d/zz-stig-hardening.conf Note: If the file zz-stig-hardening.conf does not exist, it must be created.