External Attack Surface Management, or EASM, is the practice of discovering and continuously tracking an organization’s internet-facing assets and exposures. These assets can include domains, subdomains, IP addresses, cloud services, web applications, APIs, certificates, and forgotten infrastructure that is still reachable from the public internet.
EASM matters because attackers usually start with what they can see from outside. A missed server, exposed database, or unmanaged cloud endpoint can become an entry point for scanning, credential attacks, exploit attempts, or data theft. Defenders use EASM to build an outside-in inventory, correlate assets to owners, and identify what should be patched, restricted, monitored, or removed. The most effective programs connect discovery to remediation, turning visibility into reduced exposure rather than just a longer list of findings.