The Photon operating system must log IPv4 packets with impossible addresses.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-239180	PHTN-67-000109	SV-239180r675348_rule		Medium

Description
The presence of "martian" packets (which have impossible addresses) as well as spoofed packets, source-routed packets, and redirects could be a sign of nefarious network activity. Logging these packets enables this activity to be detected.

STIG	Date
VMware vSphere 6.7 Photon OS Security Technical Implementation Guide	2021-04-15

Details

Check Text ( C-42391r675346_chk )
At the command line, execute the following command: # /sbin/sysctl -a --pattern "net.ipv4.conf.(all\|default\|eth.*).log_martians" Expected result: net.ipv4.conf.all.log_martians = 1 net.ipv4.conf.default.log_martians = 1 net.ipv4.conf.eth0.log_martians = 1 If the output does not match the expected result, this is a finding. Note: The number of "ethx" lines returned is dependent on the number of interfaces. Every "ethx" entry must be set to "1".

Check Text ( C-42391r675346_chk )

At the command line, execute the following command:

# /sbin/sysctl -a --pattern "net.ipv4.conf.(all|default|eth.*).log_martians"

Expected result:

net.ipv4.conf.all.log_martians = 1
net.ipv4.conf.default.log_martians = 1
net.ipv4.conf.eth0.log_martians = 1

If the output does not match the expected result, this is a finding.

Note: The number of "ethx" lines returned is dependent on the number of interfaces. Every "ethx" entry must be set to "1".

Fix Text (F-42350r675347_fix)
At the command line, execute the following command: # for SETTING in $(/sbin/sysctl -aN --pattern "net.ipv4.conf.(all\|default\|eth.*).log_martians"); do sed -i -e "/^${SETTING}/d" /etc/sysctl.conf;echo $SETTING=1>>/etc/sysctl.conf; done