External Network Penetration Testing: Expose What Attackers See First
Your Perimeter Has More Attack Surface Than You Think
Your firewall is configured. Your VPN is live. Your domains are registered. But does any of that mean your perimeter is actually secure?
External network penetration testing answers that question the way an attacker would — by attempting to get in. We enumerate your internet-facing assets, identify exploitable weaknesses across exposed services, chain low-severity findings into realistic attack paths, and deliver a report that tells you exactly what’s vulnerable and how to fix it. Not a scan. An adversarial simulation conducted by certified pentesters who hold credentials in Communication & Network Security, Ethical Hacking, and ISO/IEC 27001 Information Security.
Engagements start from $4,500. See our pricing page for a full tier breakdown.
What We Test: Your Full External Attack Surface
Most organizations don’t have a complete inventory of their own perimeter. Forgotten subdomains, legacy VPN endpoints, misconfigured mail servers, these are real entry points, and automated scanners routinely miss the exploitability context that matters.
Our external network pentest covers:
Exposed service enumeration
TCP/UDP port scanning across all in-scope IP ranges to identify services that are either internet-accessible when they shouldn’t be or are running software versions with known CVEs.
Subdomain discovery and takeover testing
DNS brute-forcing combined with certificate transparency log analysis and CNAME takeover checks for dangling records pointing to decommissioned cloud resources. A misconfigured DNS record is all it takes to hand an attacker a trusted subdomain on a silver platter.
Unpatched and end-of-life systems
Internet-facing servers and network appliances running software with public exploits, VPN gateways, RDP services, web servers, and management interfaces running unsupported OS versions.
VPN and remote access endpoints
Authentication bypass testing, credential stuffing exposure assessment, split tunneling weaknesses, and deprecated IKE or SSL VPN implementations still listening on external interfaces.
Mail server and webmail configuration
SPF, DKIM, and DMARC misconfiguration; open relay testing; and external Outlook Web Access or Exchange exposure that could facilitate domain spoofing.
Credential exposure on external-facing assets
Login portal brute-force resistance testing, default credential checks on management interfaces, and correlation of publicly available breach data against your domains to identify reused credentials still in active use.
Administrative interface exposure
Router management panels, firewall consoles, and server administration tools reachable directly from the internet, often on non-standard ports that scanners skip.
Cloud perimeter assets (where in scope)
Public cloud storage buckets, misconfigured load balancers, and storage endpoints tied to your IP ranges or domain registrations.
Real-World Attack Scenarios We Replicate
Each scenario below reflects patterns we’ve encountered across 2,500+ engagements with clients across fintech, healthcare, e-commerce, and SaaS.
Subdomain takeover via decommissioned cloud resource. A subdomain still resolves via CNAME to an Azure Static Site or AWS S3 bucket that’s been deleted. An attacker registers the cloud resource, serves phishing content from your trusted domain, or bypasses CORS policies on the parent application. We’ve found this in production environments at companies with mature security teams.
Credential stuffing through an exposed VPN portal. A legacy SSL VPN endpoint lacks multi-factor authentication. Credentials from a public breach dataset match an active employee account. The attacker authenticates without exploiting a single vulnerability. Perimeter breached. This is the most common initial access vector in network intrusions today.
Remote code execution via unpatched perimeter appliance. A firewall management interface or an unpatched Citrix/Pulse Secure gateway is reachable on a non-standard port. A public exploit exists. Compromise takes under 10 minutes. The vector isn’t novel,it’s simply unpatched and exposed.
Sensitive data exposure via misconfigured cloud storage. A public S3 bucket tied to a marketing subdomain contains backup archives, API keys, or database exports with no authentication required. We enumerate storage tied to your registered domains as a standard step.
Domain spoofing via open mail relay. A weak SPF record or missing DMARC policy allows an attacker to spoof your domain in outbound email. Your own clients receive phishing messages that originate from your legitimate domain identity.
How We Conduct the Assessment
Our methodology is manual-led, PTES-aligned, and built around what’s actually exploitable, not just what automated tooling detects. We begin with passive OSINT and active reconnaissance to build a complete picture of your external footprint, including assets you may not know are exposed. From there, we move into service-specific exploitation attempts, chaining low-severity findings into realistic multi-step attack paths wherever the evidence supports it. Every finding is manually validated before it appears in the report, we don’t deliver scanner output dressed up as a pentest.
Compliance Requirements This Engagement Satisfies
External network penetration testing isn’t optional for regulated industries. It’s a named control requirement under several frameworks.
PCI DSS v4.0
Requirement 11.3.2 mandates external penetration testing of the cardholder data environment boundary at least annually and after significant infrastructure changes. Our report documentation is structured to satisfy QSA evidence requests. See our PCI DSS advisory page if you need help clarifying scope before you engage.
SOC 2 Type II (CC6.1, CC6.6)
Common Criteria around logical access controls and network boundary protection regularly require external penetration testing evidence to satisfy auditor inquiries during Type II assessments.
ISO 27001:2022
A.8.8 and A.8.20 address technical vulnerability management and network security controls respectively. Our CEO holds ISO/IEC 27001 Information Security Associate certification, and engagements are scoped with ISMS alignment in mind.
HIPAA §164.308(a)(8)
The technical evaluation requirement under the Security Rule applies to internet-facing systems that process or transmit ePHI. An external pentest directly satisfies this evaluation obligation for your perimeter assets.
What You Receive
Every engagement delivers a structured report package, not just a vulnerability list.
- Executive summary: Risk posture overview written for non-technical leadership and board-level readers who need the business impact framing, not the CVE numbers.
- Technical findings report: Each vulnerability documented with CVE references where applicable, CVSS scoring, proof-of-concept evidence, reproduction steps, and remediation guidance specific to your environment, not copy-pasted from a scanner template.
- Attack path documentation: Where findings chain together into a realistic compromise scenario, we map the full path from initial external access through to potential internal impact.
- Remediation priority matrix: Findings ranked by actual exploitability and business context, not raw CVSS score. A 9.8 CVSS finding on an isolated system ranks lower than a 6.5 that opens a path to your payment infrastructure.
- Letter of attestation: For use with auditors, clients, or procurement teams requiring documented evidence of penetration testing.
Download our sample penetration test report to see the exact format and depth before you commit.
Retest Included at No Extra Cost
Once you’ve remediated, we retest the specific vulnerabilities flagged in the original report at no additional charge within the agreed retest window. We verify fixes are effective, update finding statuses in the report, and issue a final remediated version. For PCI DSS and SOC 2 specifically, this remediated report is often what your auditor actually needs.
Ready to Know What’s Actually Exposed?
Send us your list of external IP ranges and domains, we’ll scope the engagement and return a fixed-price quote within 24 hours.