[Reference: https://www.sciencedirect.com/topics/computer-science/revoke-certificate, OCSP (Online Certificate Status Protocol) is a protocol that allows clients to check the revocation status of certificates in real time by querying an OCSP responder server. This would enable theorganization to determine whether it is vulnerable to the active campaign utilizing a specific vulnerability, as it would show if any certificates have been compromised or revoked. Deploying an RA (registration authority) on each branch office may not help with checking the revocation status of certificates, as an RA is responsible for verifying the identity of certificate applicants, not issuing or revoking certificates. Using Delta CRLs (certificate revocation lists) at the branches may not provide timely or accurate information on certificate revocation status, as CRLs are updated periodically and may not reflect the latest changes. Implementing an inbound BGP (Border Gateway Protocol) prefix list may not help with checking the revocation status of certificates, as BGP is a protocol for routing network traffic between autonomous systems, not verifying certificates. Verified References: https://www.comptia.org/blog/what-is-ocsp https://partners.comptia.org/docs/default-source/resources/casp-content-guide, , , , ]