The F5 BIG-IP appliance providing user authentication intermediary services using PKI-based user authentication must implement a local cache of revocation data to support path discovery and validation in case of the inability to access revocation information via the network.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-266154	SRG-NET-000345-ALG-000099	F5BI-AP-300054	SV-266154r1024381_rule	2024-09-20	1

Description
Without configuring a local cache of revocation data, there is the potential to allow access to users who are no longer authorized (users with revoked certificates). The intent of this requirement is to require support for a secondary certificate validation method using a locally cached revocation data, such as Certificate Revocation List (CRL), in case access to OCSP (required by CCI-000185) is not available. Based on a risk assessment, an alternate mitigation is to configure the system to deny access when revocation data is unavailable. This requirement applies to ALGs that provide user authentication intermediary services (e.g., authentication gateway or TLS gateway). This does not apply to authentication for the purpose of configuring the device itself (device management).

Description

Without configuring a local cache of revocation data, there is the potential to allow access to users who are no longer authorized (users with revoked certificates). The intent of this requirement is to require support for a secondary certificate validation method using a locally cached revocation data, such as Certificate Revocation List (CRL), in case access to OCSP (required by CCI-000185) is not available. Based on a risk assessment, an alternate mitigation is to configure the system to deny access when revocation data is unavailable. This requirement applies to ALGs that provide user authentication intermediary services (e.g., authentication gateway or TLS gateway). This does not apply to authentication for the purpose of configuring the device itself (device management).

ℹ️ Check
If the BIG-IP appliance does not provide PKI-based user authentication intermediary services, this is not applicable. From the BIG-IP GUI: 1. Access. 2. Profiles/Policies. 3. Access Profiles. 4. Click "Edit" under "Per-Session Policy" for the Access Profile. 5. Verify an "OSCP Auth" and/or "CRLDP" object is configured in the Access Profile VPE AND that the fallback branch of these objects leads to a "Deny" ending. If the BIG-IP appliance is not configured to deny access when revocation data is unavailable, this is a finding.

ℹ️ Check

If the BIG-IP appliance does not provide PKI-based user authentication intermediary services, this is not applicable. From the BIG-IP GUI: 1. Access. 2. Profiles/Policies. 3. Access Profiles. 4. Click "Edit" under "Per-Session Policy" for the Access Profile. 5. Verify an "OSCP Auth" and/or "CRLDP" object is configured in the Access Profile VPE AND that the fallback branch of these objects leads to a "Deny" ending. If the BIG-IP appliance is not configured to deny access when revocation data is unavailable, this is a finding.

✔️ Fix
From the BIG-IP GUI: 1. Access. 2. Profiles/Policies. 3. Access Profiles. 4. Click "Edit" under "Per-Session Policy" for the Access Profile. 5. Add "OCSP Auth" and/or "CRLDP" object in the Access Profile. Note: To create an OCSP Responder, go to Access >> Authentication >> OCSP Responder. Note: To create a CRLDP object, go to Access >> Authentication >> CRLDP. 6. Ensure the fallback branch of these objects goes to a "Deny" ending. 7. Click "Apply Access Policy".

✔️ Fix

From the BIG-IP GUI: 1. Access. 2. Profiles/Policies. 3. Access Profiles. 4. Click "Edit" under "Per-Session Policy" for the Access Profile. 5. Add "OCSP Auth" and/or "CRLDP" object in the Access Profile. Note: To create an OCSP Responder, go to Access >> Authentication >> OCSP Responder. Note: To create a CRLDP object, go to Access >> Authentication >> CRLDP. 6. Ensure the fallback branch of these objects goes to a "Deny" ending. 7. Click "Apply Access Policy".