Which of the following systems would be at the GREATEST risk of compromise if found to have an open vulnerability associated with perfect forward secrecy?

Endpoints initiate connections but do not aggregate encrypted traffic from many sessions, reducing their exposure compared to VPN concentrators.

VPN concentrators terminate a high volume of encrypted tunnels and depend on perfect forward secrecy to ensure that compromise of a long-term private key cannot expose previously recorded session traffic. A vulnerability undermining PFS on a VPN concentrator allows an attacker who has captured bulk encrypted VPN traffic to retroactively decrypt those sessions once the private key is obtained. This aggregation of sensitive traffic makes VPN concentrators the highest-value target for PFS-related vulnerabilities.

Virtual hosts serve application workloads and do not primarily depend on PFS for their core encryption function in the way dedicated VPN infrastructure does.

SIEMs collect and correlate log data and do not manage encrypted key-exchange sessions where PFS is a relevant protection mechanism.

Layer 2 switches operate at the data link layer and perform no encryption or key exchange, making PFS entirely inapplicable to them.