The Photon operating system must use a reverse-path filter for IPv4 network traffic.

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The Photon operating system must use a reverse-path filter for IPv4 network traffic.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-258892	PHTN-40-000229	SV-258892r933737_rule		Medium

Description
Enabling reverse path filtering drops packets with source addresses that should not have been able to be received on the interface they were received on. It should not be used on systems that are routers for complicated networks but is helpful for end hosts and routers serving small networks.

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

Details

Check Text ( C-62632r933735_chk )
At the command line, run the following command to verify IPv4 traffic is using a reverse path filter: # /sbin/sysctl -a --pattern "net.ipv4.conf.(all\|default).rp_filter" Expected result: net.ipv4.conf.all.rp_filter = 1 net.ipv4.conf.default.rp_filter = 1 If the "rp_filter" kernel parameters are not set to "1", this is a finding.

Fix Text (F-62541r933736_fix)
Navigate to and open: /etc/sysctl.d/zz-stig-hardening.conf Add or update the following lines: net.ipv4.conf.all.rp_filter = 1 net.ipv4.conf.default.rp_filter = 1 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.