DISA STIGS Viewer

NixOS must manage excess capacity, bandwidth, or other redundancy to limit the effects of information flooding types of denial-of-service (DoS) attacks.

Overview

Finding ID Version Rule ID IA Controls Severity
V-268141 ANIX-00-000980 SV-268141r1039311_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.
STIG Date
Anduril NixOS Security Technical Implementation Guide 2024-10-25

Details

Check Text (C-72065r1039309_chk)
Verify NixOS is configured to use IPv4 TCP syncookies with the following command:

$ sudo sysctl net.ipv4.tcp_syncookies

net.ipv4.tcp_syncookies = 1

If the network parameter "ipv4.tcp_syncookies" is not equal to "1" or nothing is returned, this is a finding.
Fix Text (F-71968r1039310_fix)
Configure NixOS to use IPv4 TCP syncookies by editing the following in the NixOS configuration /etc/nixos/configuration.nix:

boot.kernel.sysctl = {
"net.ipv4.tcp_syncookies"=1;
};

Rebuild the NixOS configuration with the following command:

$ sudo nixos-rebuild switch