A site-to-site VPN is an encrypted connection between networks in separate locations, such as a company office and a data center. It lets devices on each network communicate over an untrusted network, typically the internet, as though they were connected through a private link.
These connections often rely on gateways and configuration that specify network ranges, routes, encryption, and authentication. If those details are exposed, attackers may learn how internal networks are connected or identify important trust paths; exposure alone does not prove that a VPN was accessed or compromised. Defenders should restrict access to VPN documentation and configurations, use strong authentication and encryption, and review connected networks and routes regularly.