Nutanix AOS must be configured to use syncookies to limit denial-of-service (DoS) attacks.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-254228	NUTX-OS-001510	SV-254228r846772_rule		Medium

Description
DoS is a condition when a resource is not available for legitimate users. When this occurs, the organization either cannot accomplish its mission or must operate at degraded capacity. Managing excess capacity ensures that sufficient capacity is available to counter flooding attacks. Employing increased capacity and service redundancy may reduce the susceptibility to some DoS attacks. Managing excess capacity may include, for example, establishing selected usage priorities, quotas, or partitioning.

Description

DoS is a condition when a resource is not available for legitimate users. When this occurs, the organization either cannot accomplish its mission or must operate at degraded capacity. Managing excess capacity ensures that sufficient capacity is available to counter flooding attacks. Employing increased capacity and service redundancy may reduce the susceptibility to some DoS attacks. Managing excess capacity may include, for example, establishing selected usage priorities, quotas, or partitioning.

STIG	Date
Nutanix AOS 5.20.x OS Security Technical Implementation Guide	2022-08-24

Details

Check Text ( C-57713r846770_chk )
Confirm Nutanix AOS is configured to use syncookies. $ sysctl net.ipv4.tcp_syncookies net.ipv4.tcp_syncookies = 1 If the value is not "1", this is a finding. Check the saved value of TCP syncookies with the following command: $ sudo grep -i net.ipv4.tcp_syncookies /etc/sysctl.conf /etc/sysctl.d/* \| grep -v '#' If no output is returned, this is a finding.

Fix Text (F-57664r846771_fix)
Configure Nutanix AOS to use TCP syncookies by running the following command: $ sudo sysctl -w net.ipv4.tcp_syncookies=1 If "1" is not the system's default value, add or update the following line in "/etc/sysctl.conf": net.ipv4.tcp_syncookies = 1