01Introduction
Attackers start with what they can reach from the internet. Most organizations can't list all of it: forgotten subdomains, test environments, acquired company assets and SaaS tenants that nobody registered with IT.
02What is EASM?
External attack surface management (EASM) is the continuous discovery, inventory and assessment of an organization's internet-facing assets from an outside-in perspective, without agents or credentials. It is the external subset of attack surface management.
03How EASM works
It works the way an attacker's reconnaissance does, on a loop.
- 1.
Seed and expand
Start from known domains and brand names, then pivot through DNS, certificate transparency logs, WHOIS and ASN data.
- 2.
Fingerprint
Identify what runs on each asset: software, versions, open ports, login pages and APIs.
- 3.
Assess
Check for known CVEs, misconfigurations, expired certificates, exposed admin panels and leaked secrets.
- 4.
Monitor for change
Rescan continuously and alert when a new asset appears or an existing one changes.
04Threats and risks
What EASM catches is what attackers find first.
Shadow IT
Services launched outside the security team's view, with default settings.
Forgotten assets
Old marketing sites, staging servers and dangling DNS records open to subdomain takeover.
Exposed services
Databases, RDP, Kubernetes dashboards and storage buckets reachable from the internet.
Alert volume
Discovery without validation produces long lists of possible issues with no proof of which matter.
05How Parameter helps
Parameter pairs discovery with exploitation, so each exposure comes with proof. See external attack surface management.
Outside-in discovery
Continuously maps domains, services and APIs the way an attacker would.
Validated findings
The pentesting agents test what they find and report only exposures they can exploit.
Cloud context
Cloud Security ties an exposed asset back to the account, identity and data behind it.
