UBTU-16-030050 - An application firewall must employ a deny-all, allow-by-exception policy for allowing connections to other systems.

Information

Failure to restrict network connectivity only to authorized systems permits inbound connections from malicious systems. It also permits outbound connections that may facilitate exfiltration of DoD data.

Satisfies: SRG-OS-000297-GPOS-00115, SRG-OS-000480-GPOS-00231

NOTE: Nessus has provided the target output to assist in reviewing the benchmark to ensure target compliance.

Solution

Configure the Uncomplicated Firewall to employ a deny-all, allow-by-exception policy for allowing connections to other systems.

Remove any service that is not needed or documented by the organization with the following command (replace [NUMBER] with the rule number):

# sudo ufw delete [NUMBER]

Another option would be to set the Uncomplicated Firewall back to default with the following commands:

# sudo ufw default deny incoming
# sudo ufw default allow outgoing

Note: UFW's defaults are to deny all incoming connections and allow all outgoing connections.

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_CAN_Ubuntu_16-04_LTS_V2R3_STIG.zip

Item Details

Category: ACCESS CONTROL, SECURITY ASSESSMENT AND AUTHORIZATION, CONFIGURATION MANAGEMENT

References: 800-53|AC-17(1), 800-53|CA-3(5), 800-53|CM-6b., CAT|II, CCI|CCI-000366, CCI|CCI-002080, CCI|CCI-002314, Rule-ID|SV-215113r610931_rule, STIG-ID|UBTU-16-030050, STIG-Legacy|SV-90487, STIG-Legacy|V-75807, Vuln-ID|V-215113

Plugin: Unix

Control ID: 06fc55e5232d95ea9cece6c30be95088781ab292baba75c93e32e4e080268df1