Ethical hackers and security professionals use attackers’ techniques to find the entry points into a company’s infrastructure. They simulate attacks under controlled conditions to uncover weak spots, using software for attacks such as brute force and SQL injection, and sometimes hardware built for testing. When the test ends, they share their findings with the company’s security team, explain each vulnerability and recommend fixes.<\/p>\n\n\n\n
Penetration testing supports risk assessment, security awareness, reputation protection and compliance. It is usually done by an outside firm, so the evaluation is unbiased and reflects how a real attacker sees you. Regular tests are recommended because attacks keep increasing. Depending on scope, a test can also cover physical security and the people in the organization, which is known as social engineering testing.<\/p>\n\n\n\n
External penetration testing: scope and methodology<\/h2>\n\n\n\n
An external penetration test protects your internet-facing assets. The tester plays the part of a real attacker with no access, trying to exploit vulnerabilities from the outside.<\/p>\n\n\n\n
How an external test runs:<\/p>\n\n\n\n
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- Planning and reconnaissance.<\/strong> First we define the scope: IP addresses and ranges, domains, subdomains and cloud assets. We also agree the rules of engagement, which set the objectives, timelines and how we communicate during the test.<\/li>\n\n\n\n
- Execution.<\/strong> We gather information about the target through passive and active reconnaissance, run vulnerability scans with tools such as Nessus, then test by hand to confirm and exploit what we find.<\/li>\n\n\n\n
- Post-execution.<\/strong> The test ends with a full report and a debrief covering the findings, the vulnerabilities we exploited and our recommendations. You get clear steps to strengthen your defenses.<\/li>\n<\/ol>\n\n\n\n
Internal penetration testing: scope and methodology<\/h2>\n\n\n\n
An internal penetration test protects your internal network from threats that are already inside it.<\/p>\n\n\n\n
How an internal test runs:<\/p>\n\n\n\n
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- Initial phase<\/strong>\n\n
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- Information gathering:<\/strong> identifying targets such as servers, workstations and network equipment.<\/li>\n\n\n\n
- Scope definition:<\/strong> based on the number of live hosts on the internal network.<\/li>\n<\/ul>\n<\/li>\n\n\n\n
- Testing<\/strong>\n\n
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- Internal network scans:<\/strong> detecting known trojans and checking the security configuration of third-party systems.<\/li>\n\n\n\n
- Finding and exploiting vulnerabilities:<\/strong> port scanning, system fingerprinting and manual vulnerability testing.<\/li>\n\n\n\n
- Assessing security controls:<\/strong> firewalls, IDS and IPS, and database security.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n
What an internal test sets out to show:<\/p>\n\n\n\n
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- Insider threats.<\/strong> Vulnerabilities that malicious insiders or insecure third-party vendors could use.<\/li>\n\n\n\n
- Lateral movement.<\/strong> How far an attacker can move through the network, which exposes gaps in policy enforcement and system maintenance.<\/li>\n\n\n\n
- Savings.<\/strong> Internal weaknesses found before they turn into a costly data breach.<\/li>\n<\/ul>\n\n\n\n
Internal testing complements external testing. Together they protect you against threats from both directions.<\/p>\n\n\n\n
Key differences: external vs internal penetration testing<\/h2>\n\n\n\n
![\"External](\"https:\/\/krylosecurity.com\/blog\/wp-content\/uploads\/2026\/10\/external-vs-internal-pentesting-compare-2.jpg\")
<\/figure>\n\n\n\nThe attacker’s position.<\/strong> An external test simulates an attacker with no prior access and looks for weaknesses an outsider could exploit. An internal test assumes the attacker already has access, perhaps a disgruntled employee or a stolen laptop, and measures the damage they could do from inside.<\/p>\n\n\n\n
Areas of focus.<\/strong> External tests target public networks and internet-facing assets such as web applications, with attention to admin features and any system that could expose sensitive data. Internal tests concentrate on the internal network: insider threats, privilege escalation and credential theft.<\/p>\n\n\n\n
Frequency and cost.<\/strong> External tests are usually bought from an outside firm, often once or twice a year, and focus on the common threats that change fastest. Internal tests can be run by an in-house security team or an outside firm. Insider attacks are less common than external ones, but when they happen they tend to do more damage, because insiders know where the important systems are.<\/p>\n\n\n\n
Most organizations need both kinds of test to cover vulnerabilities from outside and from within. If you are not sure where to start, our network penetration testing<\/a> covers external and internal testing in one engagement, scoped to your environment.<\/p>\n\n\n\n
Why you need both<\/h2>\n\n\n\n
They limit the impact of an attack and speed up recovery.<\/strong> Regular internal and external testing means your team has practised reporting, cleanup and getting the business running again. Together, the two tests show every weak link and route to unauthorized access.<\/p>\n\n\n\n
They support compliance and data protection.<\/strong> Testing helps you meet industry regulations, such as PCI DSS, which requires both internal and external penetration tests. Regular testing also keeps your security measures effective as threats change. See penetration testing for compliance<\/a> for what each standard asks for.<\/p>\n\n\n\n
They give you a realistic picture.<\/strong> Both tests simulate real attacks, so you see your security as an attacker would. The reports list each vulnerability, its risk, how hard it was to exploit and how to fix it. Annual internal and external tests keep your policies current and your defenses ahead of attackers.<\/p>\n\n\n\n
Conclusion<\/h2>\n\n\n\n
External and internal penetration tests answer different questions: how someone gets in, and how far they get once inside. Running both gives you a complete assessment and reduces your exposure to outside attackers and insiders alike. Threats keep changing, so keep testing, fix what the reports find, and use the results to meet the regulations that apply to you.<\/p>\n\n\n\n
To strengthen your security with professional external and internal penetration testing, contact us<\/a>.<\/p>\n\n\n\n
- Lateral movement.<\/strong> How far an attacker can move through the network, which exposes gaps in policy enforcement and system maintenance.<\/li>\n\n\n\n
- Finding and exploiting vulnerabilities:<\/strong> port scanning, system fingerprinting and manual vulnerability testing.<\/li>\n\n\n\n
- Scope definition:<\/strong> based on the number of live hosts on the internal network.<\/li>\n<\/ul>\n<\/li>\n\n\n\n
- Information gathering:<\/strong> identifying targets such as servers, workstations and network equipment.<\/li>\n\n\n\n
- Execution.<\/strong> We gather information about the target through passive and active reconnaissance, run vulnerability scans with tools such as Nessus, then test by hand to confirm and exploit what we find.<\/li>\n\n\n\n