The F5 BIG-IP appliance that provides intermediary services for HTTP must inspect inbound and outbound HTTP traffic for protocol compliance and protocol anomalies.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-266149	SRG-NET-000512-ALG-000066	F5BI-AP-300043	SV-266149r1024844_rule	2024-09-20	1

Description
Application protocol anomaly detection examines application layer protocols such as HTTP to identify attacks based on observed deviations in the normal RFC behavior of a protocol or service. This type of monitoring allows for the detection of known and unknown exploits which exploit weaknesses of commonly used protocols. Since protocol anomaly analysis examines the application payload for patterns or anomalies, an HTTP proxy must be included in the ALG. This ALG will be configured to inspect inbound and outbound HTTP communications traffic to detect protocol anomalies such as malformed message and command insertion attacks. All inbound and outbound traffic, including HTTPS, must be inspected. However, the intention of this policy is not to mandate HTTPS inspection by the ALG. Typically, HTTPS traffic is inspected either at the source, destination and/or is directed for inspection by organizationally-defined network termination point.

Description

Application protocol anomaly detection examines application layer protocols such as HTTP to identify attacks based on observed deviations in the normal RFC behavior of a protocol or service. This type of monitoring allows for the detection of known and unknown exploits which exploit weaknesses of commonly used protocols. Since protocol anomaly analysis examines the application payload for patterns or anomalies, an HTTP proxy must be included in the ALG. This ALG will be configured to inspect inbound and outbound HTTP communications traffic to detect protocol anomalies such as malformed message and command insertion attacks. All inbound and outbound traffic, including HTTPS, must be inspected. However, the intention of this policy is not to mandate HTTPS inspection by the ALG. Typically, HTTPS traffic is inspected either at the source, destination and/or is directed for inspection by organizationally-defined network termination point.

ℹ️ Check
If the BIG-IP appliance does not provide intermediary/proxy services for HTTP communications traffic, this is not applicable. Application Security Policy: From the BIG-IP GUI: 1. Security. 2. Application Security. 3. Policy Building. 4. Learning and Blocking Settings. 5. Verify the correct policy is selected from the drop-down in the upper left. 6. Expand "HTTP protocol compliance failed". 7. Verify the proper inspection criteria are selected. HTTP Virtual Server: From the BIG-IP GUI: 1. Local Traffic. 2. Virtual Servers. 3. Virtual Server List. 4. Click the name of the HTTP Virtual Server. 5. Security >> Policies tab. 6. Verify the correct policy is selected for "Application Security Policy". If the BIG-IP appliance is not configured to inspect inbound and outbound HTTP communications traffic for protocol compliance and protocol anomalies, this is a finding.

ℹ️ Check

If the BIG-IP appliance does not provide intermediary/proxy services for HTTP communications traffic, this is not applicable. Application Security Policy: From the BIG-IP GUI: 1. Security. 2. Application Security. 3. Policy Building. 4. Learning and Blocking Settings. 5. Verify the correct policy is selected from the drop-down in the upper left. 6. Expand "HTTP protocol compliance failed". 7. Verify the proper inspection criteria are selected. HTTP Virtual Server: From the BIG-IP GUI: 1. Local Traffic. 2. Virtual Servers. 3. Virtual Server List. 4. Click the name of the HTTP Virtual Server. 5. Security >> Policies tab. 6. Verify the correct policy is selected for "Application Security Policy". If the BIG-IP appliance is not configured to inspect inbound and outbound HTTP communications traffic for protocol compliance and protocol anomalies, this is a finding.

✔️ Fix
Application Security Policy: From the BIG-IP GUI: 1. Security. 2. Application Security. 3. Policy Building. 4. Learning and Blocking Settings. 5. Select the correct policy from the drop-down in the upper left. 6. Expand "HTTP protocol compliance failed". 7. Select the proper inspection criteria. 8. Click "Save". 9. Click "Apply Policy". HTTP Virtual Server: From the BIG-IP GUI: 1. Local Traffic. 2. Virtual Servers. 3. Virtual Server List. 4. Click the name of the HTTP virtual server. 5. Security >> Policies tab. 6. Set "Application Security Policy" to "Enabled". 7. Select the correct policy from the drop-down. 8. Click "Update". Refer to vendor documentation for more information.

✔️ Fix

Application Security Policy: From the BIG-IP GUI: 1. Security. 2. Application Security. 3. Policy Building. 4. Learning and Blocking Settings. 5. Select the correct policy from the drop-down in the upper left. 6. Expand "HTTP protocol compliance failed". 7. Select the proper inspection criteria. 8. Click "Save". 9. Click "Apply Policy". HTTP Virtual Server: From the BIG-IP GUI: 1. Local Traffic. 2. Virtual Servers. 3. Virtual Server List. 4. Click the name of the HTTP virtual server. 5. Security >> Policies tab. 6. Set "Application Security Policy" to "Enabled". 7. Select the correct policy from the drop-down. 8. Click "Update". Refer to vendor documentation for more information.