External IT Infrastructure Penetration Testing
93% of cyberattacks start from the internet. We test everything visible externally: websites, applications, VPN, email, public APIs. Find vulnerabilities before attackers get inside.
What is external penetration testing of IT infrastructure?
External penetration testing simulates a real internet-based attack on everything visible from outside your organization — public IPs, web applications, VPN, email servers, APIs — using OSINT reconnaissance followed by active exploitation attempts with working Proof-of-Concept. nFlo OSCP-, OSWE-, and OSCE-certified pentesters work according to PTES, OWASP, and NIST SP 800-115 standards, delivering both a technical IT report and an executive business risk report required for NIS2 and DORA compliance.
Attacker needs only one vulnerability to get in
Comprehensive external attack simulation
Reconnaissance
Information gathering like a real attacker
Exploitation
Vulnerability verification through exploits
Risk Assessment
Real business risk evaluation
Ransomware Attack via Public RDP - Case Study
A mid-sized manufacturing company lost 3 days of production due to ransomware attack. Entry point? RDP server exposed to internet on default port 3389 with weak password. Attacker found it via Shodan in 15 minutes. Incident cost: €110K (downtime, ransom, system rebuild).
Without external penetration testing:
- Don’t know what attacker sees from internet
- Public services with vulnerabilities (VPN, RDP, portals)
- Data leaks in public repositories (GitHub, Pastebin)
- No awareness of real attack surface
We Think Like Attackers, Act Like Pentesters
We simulate real attack - from Google reconnaissance to exploitation. We don’t just scan for vulnerabilities, we actually try to get inside.
What you get:
- Full OSINT reconnaissance (domains, subdomains, IPs, employee data)
- Identification of all public services and applications
- Vulnerability testing per OWASP, PTES, NIST
- Exploitation attempts with working Proof-of-Concept
- Real risk assessment for each vulnerability
- Technical report for IT team
- Executive report for management with business impact
- Recommendations prioritized by risk
Reconnaissance Tools and Techniques
We employ a multi-phase approach to external testing, combining automation with manual expert analysis.
OSINT and Passive Reconnaissance
- Subfinder, Amass, and Assetfinder for subdomain enumeration (DNS brute-force, certificate transparency, web scraping)
- Shodan, Censys, and FOFA for identifying exposed services and technologies
- theHarvester for collecting email addresses, hosts, and subdomains from public sources
- Google Dorking and GitHub dorking to uncover leaks (API keys, credentials, internal documentation)
- SpiderFoot for automated OSINT data correlation
Active Scanning and Vulnerability Assessment
- Nmap with dedicated NSE scripts for port scanning and service fingerprinting
- Nuclei with a library of 8,000+ templates for detecting known vulnerabilities, misconfigurations, and exposed panels
- Burp Suite Professional for web application and API testing (OWASP Top 10)
- testssl.sh for TLS/SSL configuration verification (cipher suites, certificates, protocols)
- Email configuration checks: SPF, DKIM, DMARC — protection against spoofing
Compliance-Ready Reporting The technical report classifies vulnerabilities using CVSS v3.1 with attack vector descriptions, exploitation conditions, and business impact. The executive report for management presents results in business risk context — no technical jargon, with recommendations prioritized by criticality. Both reports meet documentation requirements for NIS2 (Article 21 — vulnerability management), DORA (Article 24 — resilience testing), and ISO 27001 (A.18.2 — information security reviews). Upon request, we provide an attestation letter confirming test completion — useful for auditors and business partners.
Who Is It For?
This service is for you if:
- You have public services accessible from internet (websites, apps, VPN)
- You must meet regulatory requirements (NIS2, DORA, ISO 27001)
- You want to know how your company looks to an attacker
- You need external validation of perimeter security
Test Scope
What We Test
1. Reconnaissance
- Subdomains and DNS infrastructure
- Public IP addresses and open ports
- Technologies and software versions
- Employee information (LinkedIn, OSINT)
- Data leaks (GitHub, Pastebin, Shodan)
2. Vulnerability Assessment
- Web applications and APIs
- Email servers (SMTP, anti-spoofing)
- VPN and remote access (RDP, SSH, VNC)
- Network services (FTP, DNS, SMB)
- SSL/TLS certificates and configuration
3. Exploitation
- SQL Injection, XSS, RCE
- Password attacks (brute-force, credential stuffing)
- CVE exploitation (known vulnerabilities)
- Configuration weaknesses
- Business logic flaws
4. Post-Exploitation
- Lateral movement (if in scope)
- Data exfiltration simulation
- Persistence techniques
- Privilege escalation
Methodology
We work according to recognized standards:
- PTES (Penetration Testing Execution Standard)
- OWASP Testing Guide for web applications
- NIST SP 800-115 for infrastructure testing
Contact your account manager
Discuss External IT Infrastructure Penetration Testing with your dedicated account manager.
How we work
Our proven service delivery process.
Scoping
Define scope: domains, IPs, applications
Reconnaissance
Open source information gathering
Vulnerability Assessment
Scanning and vulnerability identification
Exploitation
Attempts to exploit found vulnerabilities
Reporting
Report with PoC and prioritized actions
Benefits for your business
What you gain by choosing this service.
Peace Before Attack
Know your perimeter is secure
Regulatory Compliance
Meet NIS2, DORA, ISO 27001 requirements
Avoid Costly Incidents
Detect vulnerabilities before attackers exploit them
Lower Insurance Premiums
Insurers value proactive testing
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Read more →Frequently Asked Questions
Common questions about External IT Infrastructure Penetration Testing.
What exactly do you test during an external pentest?
Everything visible from the internet: public IPs and open ports, web applications, VPN, email servers, APIs, SSL/TLS certificates. We also check for data leaks in public repositories (GitHub, Shodan) and employee information (OSINT).
How long does an external penetration test take?
Typically 3-7 business days, depending on the number of public IP addresses and applications. For a small company (1-5 public IPs) 3 days is sufficient. For a large organization with many applications and subdomains, 5-7 days are needed.
Can the tests cause downtime of our services?
No. We use controlled techniques and avoid DoS attacks. Before testing, we agree on scope and testing hours. If a critical vulnerability is discovered (e.g., RCE), we immediately notify the IT team.
What certifications do your pentesters hold?
Our pentesters hold OSCP, OSWE, and OSCE certifications. We work according to PTES, OWASP Testing Guide, and NIST SP 800-115 methodologies.
Will the report help us meet NIS2 or DORA requirements?
Yes. An external pentest report is one of the required compliance elements for NIS2 and DORA. We deliver a technical report for IT and an executive report for management with business risk assessment.