Nutanix AOS must protect against or limit the effects of denial-of-service (DoS) attacks by ensuring the operating system is implementing rate-limiting measures on impacted network interfaces.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-254227	NUTX-OS-001500	SV-254227r958902_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. This requirement addresses the configuration of the operating system to mitigate the impact of DoS attacks that have occurred or are ongoing on system availability. For each system, known and potential DoS attacks must be identified and solutions for each type implemented. A variety of technologies exist to limit or, in some cases, eliminate the effects of DoS attacks (e.g., limiting processes or establishing memory partitions). Employing increased capacity and bandwidth, combined with service redundancy, may reduce the susceptibility to some DoS attacks.

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. This requirement addresses the configuration of the operating system to mitigate the impact of DoS attacks that have occurred or are ongoing on system availability. For each system, known and potential DoS attacks must be identified and solutions for each type implemented. A variety of technologies exist to limit or, in some cases, eliminate the effects of DoS attacks (e.g., limiting processes or establishing memory partitions). Employing increased capacity and bandwidth, combined with service redundancy, may reduce the susceptibility to some DoS attacks.

STIG	Date
Nutanix AOS 5.20.x OS Security Technical Implementation Guide	2024-06-18

Details

Check Text ( C-57712r846767_chk )
Confirm Nutanix AOS protects against or limits the effects of DoS attacks by ensuring that a rate-limiting measures are enabled. $ /sbin/sysctl -a \| grep 'net.ipv4.tcp_invalid_ratelimit' net.ipv4.tcp_invalid_ratelimit = 500 If "net.ipv4.tcp_invalid_ratelimit" has a value of "0", this is a finding. If "net.ipv4.tcp_invalid_ratelimit" has a value greater than "1000" and is not documented with the Information System Security Officer (ISSO), this is a finding.

Check Text ( C-57712r846767_chk )

Confirm Nutanix AOS protects against or limits the effects of DoS attacks by ensuring that a rate-limiting measures are enabled.

$ /sbin/sysctl -a | grep 'net.ipv4.tcp_invalid_ratelimit'
net.ipv4.tcp_invalid_ratelimit = 500

If "net.ipv4.tcp_invalid_ratelimit" has a value of "0", this is a finding.

If "net.ipv4.tcp_invalid_ratelimit" has a value greater than "1000" and is not documented with the Information System Security Officer (ISSO), this is a finding.

Fix Text (F-57663r846768_fix)
Configure Nutanix AOS firewall services by running the following command: $ sudo salt-call state.sls security/CVM/iptables/init