Your perimeter is what an attacker sees first. We test every internet-facing service the way an external adversary would — finding misconfigurations, weak authentication, and forgotten infrastructure that turn a quiet recon scan into a real breach.
What is External Network Penetration Testing?
External network penetration testing simulates an attacker on the public internet probing your organization’s externally-facing infrastructure — web servers, VPNs, email gateways, cloud APIs, exposed admin interfaces, and anything else with a publicly routable IP.
The goal is to find the path from “anonymous attacker on the internet” to “foothold inside your environment.” That path almost always exists. The question is whether you find it first or your adversary does.
Why your perimeter needs hands-on testing
Public-facing infrastructure changes constantly. Cloud workloads spin up. Marketing teams stand up new subdomains. Old admin panels get forgotten. SSL certificates expire and get reissued in ways that change the exposed service. Every change is a potential opening — and your perimeter is the first thing an attacker sees.
Automated scans catch the obvious: unpatched CVEs, default credentials, expired certs. They miss the things that actually let attackers in:
- Forgotten infrastructure — that test environment from 2022 still responding on a residential IP
- Misconfigured authentication — SSO portals that leak valid usernames, password reset flows that disclose account existence
- Chained vulnerabilities — three medium-severity findings that combine into a critical breach path no single scanner would flag
- Logic flaws — endpoints that work as designed but expose data through intended functionality used in unintended ways
A manual external pentest finds these. A scan does not.
CyberBullet’s methodology
1. Scoping & Authorization
We define the engagement boundary precisely before testing starts: in-scope IP ranges and domains, explicit out-of-bounds targets (third-party hosted services, customer environments), testing windows, and emergency-stop procedures. Authorization letters are exchanged in writing.
2. Passive Reconnaissance & OSINT
Before sending a single packet, we map your external footprint using public sources only — DNS records, certificate transparency logs, search engines, code repositories, and internet-wide scan data. This phase typically discovers 15-30% more attack surface than the client originally provided.
3. Active Discovery & Service Enumeration
We then enumerate live services across your in-scope assets — open ports, running software versions, authentication mechanisms, and protocol-level configurations. Every result is correlated against known vulnerability data.
4. Vulnerability Identification & Validation
We combine targeted scanning (for breadth) with manual inspection (for the findings that matter). Every potential issue is validated by hand before it makes the report — no false positives.
5. Exploitation
For confirmed vulnerabilities with attacker value, we attempt exploitation to prove impact. This is what separates a pentest from a scan: we don’t just say “this CVE applies” — we demonstrate what an attacker would actually achieve with it.
6. Reporting & Remediation Guidance
The deliverable is the report. Every finding is paired with: severity rated on real exploitability (not just CVSS), reproducible proof of exploit, and specific remediation guidance your team can act on this week.
Frameworks we map findings to
- CIS Critical Security Controls (v8) — perimeter and asset management
- NIST Cybersecurity Framework (CSF 2.0) — Identify and Protect functions
- PCI DSS (4.0) Requirement 11.4 — external pentest mandate
- OWASP for web-facing services
- SOC 2 Trust Services Criteria — change management and monitoring
Who this is for
- Compliance-bound organizations (PCI, SOC 2, HIPAA, NAIC) with annual external pentest requirements
- Companies with significant public-facing infrastructure — SaaS, e-commerce, fintech, public sector
- Organizations that recently shipped infrastructure changes — migrations, new product launches, M&A integrations
- Security teams that already scan but want to know what scanners miss
Our methodology
Every engagement runs through the same six phases. Manual validation isn't a finishing step — it's the product.
Scope & Authorize
We define the engagement boundary precisely before testing starts — in-scope assets, out-of-bounds targets, testing windows, and emergency-stop procedures.
- Written authorization letters exchanged before any packet leaves our infrastructure
- Signal / Slack channel established for real-time findings during the engagement
- Explicit rules of engagement reviewed with legal, IT, and business stakeholders
Passive Reconnaissance
Before a single packet touches your infrastructure, we map your external footprint using public sources only — DNS, CT logs, code repos, internet-wide scan data.
- Typically discovers 15-30% more attack surface than the client originally provided
- Certificate transparency, BGP, and GitHub exposure reporting
- OSINT profile for social engineering vectors if in scope
Active Discovery
We enumerate live services across in-scope assets — ports, software versions, auth mechanisms, and protocol configurations — correlated against current vuln data.
- Hand-tuned scanning profiles — not the default Nessus run
- Protocol-level inspection for TLS, SSH, SMB, Kerberos, LDAP
- Service fingerprinting to ground truth before any exploitation
Manual Validation
Every potential issue is validated by hand before it makes the report. No CVE-dumping. No false positives. This is what separates the engagement from a scan.
- Manual exploitation attempts for any finding of High severity or above
- Business-logic testing on top of the technical layer
- Chained vulnerabilities analyzed as a single attack path
Exploitation & Impact
For confirmed vulnerabilities with attacker value, we attempt exploitation to prove impact — not just that a CVE applies, but what it gets you.
- Proof-of-exploit captured for every confirmed critical finding
- Pivot paths mapped to the actual crown-jewel data
- Interim notification inside 24 hours for anything critical
Report & Remediate
Every finding is paired with severity rated on real exploitability, reproducible proof-of-exploit, and remediation guidance your team can ship this sprint.
- Executive summary and technical deep-dive in a single report
- Findings mapped to CIS, NIST CSF, and relevant compliance families
- Retest included — we confirm the fix before we close the finding
What you walk away with
Frameworks we map to
Findings ship mapped to the control families your regulators and auditors actually check. Governance clients use these crosswalks directly in their program documentation.
- CIS Controls v8
- NIST CSF 2.0 / 800-53
- PCI DSS 4.0
- HIPAA Security Rule
- SOC 2 Type II
- OWASP ASVS
Questions we get asked
What's the difference between an external pentest and a vulnerability scan of our public IPs?
A scan tells you which CVEs apply to your services. An external pentest answers what an attacker would actually do with what's exposed. We chain misconfigurations, abuse exposed admin panels, exploit weak SSL/TLS deployments, and pivot through DMZ services to internal trust zones — the way a real adversary would.
Do you need our IP ranges in advance, or do you discover them?
Both. We start with the IPs you provide, then expand discovery using OSINT — DNS records, certificate transparency logs, internet scan data, and BGP records — to find systems you didn't know were exposed. Shadow IT discoveries are common; one client had a forgotten test environment with production credentials hosted on a residential ISP IP from a former employee.
Will the test affect our public services or users?
Properly scoped, no. We coordinate testing windows with your team, run intrusive checks during agreed times, and use techniques that minimize service impact. Anything risky to availability requires an explicit go-ahead before execution. We've never caused a customer-facing outage.
How often should we run an external pentest?
At least annually for compliance-driven environments (PCI, HIPAA, SOC 2), and after every significant change to your perimeter — new product launches, infrastructure migrations, M&A activity, or major architectural shifts. Quarterly for high-risk environments (fintech, healthcare, public sector).
What if you find something serious mid-test?
We immediately notify your designated contact through the agreed channel — usually a Signal or dedicated Slack channel set up at kickoff. Critical findings get an interim report inside 24 hours so you can start remediation before the engagement ends, not after.