STIGQter: STIG Summary: Tri-Lab Operating System Stack (TOSS) 4 Security Technical Implementation Guide Version: 2 Release: 6 Benchmark Date: 01 Jul 2026:

A firewall must be able to protect against or limit the effects of Denial of Service (DoS) attacks by ensuring TOSS can implement rate-limiting measures on impacted network interfaces.

DISA Rule

SV-253092r958902_rule

Vulnerability Number

V-253092

Group Title

SRG-OS-000420-GPOS-00186

Rule Version

TOSS-04-040480

Severity

CAT II

CCI(s)

• CCI-002385 - Protect against or limit the effects of organization-defined types of denial of service events.

Weight

10

Fix Recommendation

Configure "nftables" to be the default "firewallbackend" for "firewalld" by adding or editing the following line in "/etc/firewalld/firewalld.conf":

FirewallBackend=nftables

Establish rate-limiting rules based on organization-defined types of DoS attacks on impacted network interfaces.

Check Contents

Verify "firewalld" has "nftables" set as the default backend:

$ sudo grep -i firewallbackend /etc/firewalld/firewalld.conf

# FirewallBackend
FirewallBackend=nftables

If the "nftables" is not set as the "firewallbackend" default, this is a finding.

Vulnerability Number

V-253092

Documentable

False

Rule Version

TOSS-04-040480

Severity Override Guidance

Verify "firewalld" has "nftables" set as the default backend:

$ sudo grep -i firewallbackend /etc/firewalld/firewalld.conf

# FirewallBackend
FirewallBackend=nftables

If the "nftables" is not set as the "firewallbackend" default, this is a finding.

Check Content Reference

M

Target Key

5469