STIGQter: STIG Summary: Red Hat Enterprise Linux 9 Security Technical Implementation Guide Version: 2 Release: 9 Benchmark Date: 01 Jul 2026:

RHEL 9 must protect against or limit the effects of denial-of-service (DoS) attacks by ensuring rate-limiting measures on impacted network interfaces are implemented.

DISA Rule

SV-257939r1044997_rule

Vulnerability Number

V-257939

Group Title

SRG-OS-000420-GPOS-00186

Rule Version

RHEL-09-251030

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 "nftables" is configured to allow rate limits on any connection to the system with the following command:

$ 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-257939

Documentable

False

Rule Version

RHEL-09-251030

Severity Override Guidance

Verify "nftables" is configured to allow rate limits on any connection to the system with the following command:

$ 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

5551