HackproofHacks
Perimeter security

External Network Penetration Testing

Everything your organization exposes to the internet is a door an attacker can try, and most organizations expose more than they realize: forgotten subdomains, old servers, management interfaces, and services that were meant to be temporary. An external network penetration test maps that perimeter and tests it the way an outside attacker with no prior access would.

This engagement models the internet-facing threat: reconnaissance, discovery of exposed services, and exploitation of the weaknesses that would give an outsider a foothold, delivered with a clear report of what is exposed and what to close.

Why the perimeter still matters

Attackers begin where you cannot hide: your public footprint. Before touching anything, a capable attacker enumerates your domains, IP ranges, and exposed services, and this reconnaissance regularly surfaces assets the organization forgot it had. A test that starts the same way finds those forgotten doors before someone else does.

The perimeter accumulates risk quietly. A staging server left online, a database exposed during a migration, an admin panel reachable from anywhere, or a service running an outdated version with a public exploit. None of these announce themselves, and any one can be the entry point for a full compromise.

External testing also underpins compliance and supplier assurance. PCI DSS requires it, many frameworks expect it, and customers assessing you as a supplier want evidence that your internet-facing systems have been independently probed. One engagement satisfies the security need and the paperwork.

What we test

Attack-surface discovery

Enumeration of your domains, subdomains, IP ranges, and exposed services using the same reconnaissance an attacker performs, to build a complete picture of what is reachable.

Exposed services and interfaces

Management panels, remote-access services, and applications that should not be internet-facing, or that are but lack adequate protection.

Vulnerable and outdated components

Internet-facing software running versions with known, exploitable vulnerabilities, and misconfigurations that weaken otherwise sound services.

Transport and email security

Weak or deprecated TLS, plaintext services, and email-security gaps that enable spoofing, checked as part of the outward-facing posture.

The report you receive

The report gives you a clear view of your perimeter. It contains:

  • An executive summary of your internet-facing exposure and its risk.
  • An inventory of the exposed assets discovered, including any you may not have expected.
  • Findings rated by severity with reproduction steps, impact, and remediation.
  • A methodology statement suitable for compliance and supplier assurance.
  • A retest and updated report once exposures are closed.

Findings we commonly report in this category

Forgotten or unmanaged assets

Subdomains, staging systems, or services exposed to the internet that the organization was not actively tracking, and therefore not patching.

Exposed management interfaces

Admin panels, remote-access services, or dashboards reachable from anywhere, offering an attacker a direct target for brute-forcing or exploitation.

Unpatched internet-facing software

Public-facing services running versions with published exploits, a common route to initial compromise.

Weak transport and email security

Deprecated TLS, plaintext services, and missing email-authentication records that enable interception or spoofing.

Frequently asked questions

What is the difference between external and internal network testing?

External testing models an attacker on the internet with no prior access, focusing on your public perimeter. Internal testing models an attacker who already has a foothold inside your network. Both are valuable, and PCI, for example, requires each.

Will you find assets we do not know about?

Often, yes. Reconnaissance regularly surfaces forgotten subdomains and exposed services, and those unmanaged assets are frequently the weakest points because nobody was maintaining them.

Is external testing safe for our live systems?

Yes. We agree clear rules of engagement, avoid destructive techniques, and coordinate timing so testing does not disrupt your operations.

How often should we run an external test?

At least annually and after significant changes to your internet-facing infrastructure. Perimeters drift over time, so a regular cadence keeps your exposure understood.

Related services

Ready to scope your external network penetration testing?

Book a free 30-minute scoping call. We agree the scope, timeline, and a fixed price up front — no obligation, and no surprises for your deadline.