STIGQter: STIG Summary: Canonical Ubuntu 22.04 LTS Security Technical Implementation Guide Version: 2 Release: 9 Benchmark Date: 01 Jul 2026:

Ubuntu 22.04 LTS must configure the Uncomplicated Firewall (ufw) to rate-limit impacted network interfaces.

DISA Rule

SV-260517r958902_rule

Vulnerability Number

V-260517

Group Title

SRG-OS-000420-GPOS-00186

Rule Version

UBTU-22-251025

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 the application firewall to protect against or limit the effects of DoS attacks by ensuring Ubuntu 22.04 LTS is implementing rate-limiting measures on impacted network interfaces.

For each service with a port listening to connections, run the following command, replacing "<service_name>" with the service that needs to be rate limited.

$ sudo ufw limit <service_name>

Rate-limiting can also be done on an interface. An example of adding a rate limit on the "ens160" interface follows:

$ sudo ufw limit in on ens160

Check Contents

Verify an application firewall is configured to rate limit any connection to the system.

Check all the services listening to the ports by using the following command:

$ ss -l46ut
Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port Process
tcp LISTEN 0 511 *:http *:*
tcp LISTEN 0 128 [::]:ssh [::]:*
tcp LISTEN 0 128 [::]:ipp [::]:*
tcp LISTEN 0 128 [::]:smtp [::]:*


For each entry, verify that the ufw is configured to rate limit the service ports by using the following command:

$ sudo ufw status
Status: active

To Action From
-- ------ ----
80/tcp LIMIT Anywhere
25/tcp LIMIT Anywhere
Anywhere DENY 240.9.19.81
443 LIMIT Anywhere
22/tcp LIMIT Anywhere
80/tcp (v6) LIMIT Anywhere
25/tcp (v6) LIMIT Anywhere
22/tcp (v6) LIMIT Anywhere (v6)

25 DENY OUT Anywhere
25 (v6) DENY OUT Anywhere (v6)

If any port with a state of "LISTEN" that does not have an action of "DENY", is not marked with the "LIMIT" action, this is a finding.

Vulnerability Number

V-260517

Documentable

False

Rule Version

UBTU-22-251025

Severity Override Guidance

Verify an application firewall is configured to rate limit any connection to the system.

Check all the services listening to the ports by using the following command:

$ ss -l46ut
Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port Process
tcp LISTEN 0 511 *:http *:*
tcp LISTEN 0 128 [::]:ssh [::]:*
tcp LISTEN 0 128 [::]:ipp [::]:*
tcp LISTEN 0 128 [::]:smtp [::]:*


For each entry, verify that the ufw is configured to rate limit the service ports by using the following command:

$ sudo ufw status
Status: active

To Action From
-- ------ ----
80/tcp LIMIT Anywhere
25/tcp LIMIT Anywhere
Anywhere DENY 240.9.19.81
443 LIMIT Anywhere
22/tcp LIMIT Anywhere
80/tcp (v6) LIMIT Anywhere
25/tcp (v6) LIMIT Anywhere
22/tcp (v6) LIMIT Anywhere (v6)

25 DENY OUT Anywhere
25 (v6) DENY OUT Anywhere (v6)

If any port with a state of "LISTEN" that does not have an action of "DENY", is not marked with the "LIMIT" action, this is a finding.

Check Content Reference

M

Target Key

5594