The Photon operating system must use TCP syncookies.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-239109	PHTN-67-000037	SV-239109r816622_rule		Medium

Description
A TCP SYN flood attack can cause a denial of service by filling a system's TCP connection table with connections in the SYN_RCVD state. Syncookies can be used to track a connection when a subsequent ACK is received, verifying the initiator is attempting a valid connection and is not a flood source. This feature is activated when a flood condition is detected and enables the system to continue servicing valid connection requests. Satisfies: SRG-OS-000142-GPOS-00071, SRG-OS-000420-GPOS-00186

Description

A TCP SYN flood attack can cause a denial of service by filling a system's TCP connection table with connections in the SYN_RCVD state. Syncookies can be used to track a connection when a subsequent ACK is received, verifying the initiator is attempting a valid connection and is not a flood source. This feature is activated when a flood condition is detected and enables the system to continue servicing valid connection requests. Satisfies: SRG-OS-000142-GPOS-00071, SRG-OS-000420-GPOS-00186

STIG	Date
VMware vSphere 6.7 Photon OS Security Technical Implementation Guide	2022-01-03

Details

Check Text ( C-42320r816620_chk )
At the command line, execute the following command: # /sbin/sysctl -a --pattern tcp_syncookies Expected result: net.ipv4.tcp_syncookies = 1 If the output does not match the expected result, this is a finding.

Fix Text (F-42279r816621_fix)
Open /etc/sysctl.conf with a text editor. Add or update the following line: net.ipv4.tcp_syncookies=1 Run the following command to load the new setting: # /sbin/sysctl --load