Penetration testing is the practice of checking the security weaknesses of application software, networks, computers and devices, wireless systems, and employees. Penetration tests can be either external or internal depending on the goal of the project.
An external penetration test researches and attempts to exploit vulnerabilities that could be performed by an external user without access and permissions. An internal penetration test, or assumed breach test, assesses the risk of a threat actor who also already achieved initial access into your systems to determine what level of information can be exposed.
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What Is An External Penetration Test?
External penetration testing consists of testing vulnerabilities to review the chances of being attacked by any remote attacker. By exploiting the found vulnerabilities it identifies the information being exposed to outsiders.
The main objective of this test is to simulate an attack on the external network by mimicking the actions of an actual threat actor.
This type of penetration testing attempts to find and exploit vulnerabilities in a system to gain initial access to the internal network.
As a result, the test will show whether the implemented security measures are enough to secure an organization and assess its capability to defend against any external attack.
Examples Of An External Penetration Test
- Configuration & Deployment Management Testing.
- Identity Management Testing.
- Authentication Testing.
- Authorization Testing.
- Session Management Testing, Input Validation Testing.
- Testing for weak Cryptography.
- Business Logic Testing.
- Client Side Testing.
- Testing for Error Handling.
External Penetration Testing Methods
- Footprinting.
- Checking for public information and other information leakages.
- System Scanning/Port Scanning/Service Scanning for vulnerabilities.
- Manual testing identified vulnerabilities.
- IDS/IPS Testing.
- Password Strength Testing.
When Should You Choose An External Penetration Test?
- External Threat Focus: External pen tests focus on threats originating from outside the organization’s network. These are often the most common types of threats, as they can come from any location worldwide.
- Internet-facing Assets: External pen tests specifically target your internet-facing assets, such as your website, email server, and remote access portals. These are often the first targets of an attack.
- Preventing Unauthorized Access: By identifying vulnerabilities, you can prevent attackers from gaining unauthorized access to your internal network.
- Real-world Attack Simulation: External pen tests simulate real-world attacks from a hacker’s perspective. This can give you a better understanding of your vulnerabilities as they would appear to a potential attacker.
- Unbiased Perspective: An external pen test provides an unbiased perspective of your network security, as the testers are not familiar with your internal network architecture.
What Is An Internal Penetration Test?
An internal penetration test uses a different way of dealing with the attacks and typically comes into the picture after the completion of an external penetration test.
In this test, the main focus is to identify what could be accomplished by an attacker who has internal access to your network or applications.
Before engaging with a vendor consider having the following checklist of items available:
- Your goals for performing a pen test.
- The number of internal workstations on the network.
- The number of servers.
- The total number of internal and external IPs.
Once those vulnerabilities are identified, testers may exploit them, or document them in the final report to discover the impact of an attack and show the weakness/entry points to the organization.
Internal penetration testing is not just limited to exploiting internal network vulnerabilities, but it also includes privilege escalation, malware spreading, man-in-the-middle attacks (MITM), credential stealing, monitoring, information leakage, or any other malicious activity.
You might be wondering why you would conduct an internal penetration test, to begin with, given your systems are supposedly secure from any external threats.
However, internal tests provide the results to an organization that should an attacker manage to gain access equivalent to an insider.
Or if any malicious internal user tries to break the security, what impact it could have in terms of disclosure, misuse, alteration, or destruction of the organization’s confidential information.
Examples Of An Internal Penetration Test
- White Box Testing.
- Gray Box Testing.
- Black Box Testing.
- Social Engineering.
- Physical Penetration Testing.
- Wireless Penetration Testing.
- Network Service Testing.
- Client Side Testing.
- Web Application Testing.
- Database Testing.
- Mobile Application Testing.
- Cloud Testing.
- IoT Testing.
Internal Penetration Testing Methods
- Internal Network Scanning,
- Port Scanning and System Fingerprinting,
- Finding And Exploiting Vulnerabilities.
- Manual Vulnerability Testing and Verification,
- Administrator Privileges Escalation Testing.
- Password Strength Testing.
- Network Equipment Security Controls Testing.
- Database Security Controls Testing.
- Internal Network Scan for Known Trojans.
- Third-Party/Vendor Security Configuration Testing.
When Should You Choose An Internal Penetration Test?
- Insider Threats: Internal pen tests focus on threats originating from inside the organization’s network. These can come from disgruntled and unaware employees, contractors, or attackers who have already gained access to your network.
- Access Control: Internal pen tests can help you understand if your access controls are working as expected and if privileges can be escalated.
- Post-Breach Analysis: If an attacker has breached your external defenses, an internal pen test can help identify what resources the attacker can access.
- Insider Threat Simulation: Internal pen tests simulate attacks from an insider’s perspective, providing insight into what an insider could accomplish.
- Network Security: An internal pen test provides a detailed view of your network security from within, which can be different from how it appears from the outside.
- Sensitive Data Access: Internal pen tests can help identify if an attacker with initial access can reach sensitive data within your web applications.
- Session Management: It can test the robustness of session management and authentication mechanisms of your web applications.
- Privilege Escalation: It can reveal if an attacker can escalate privileges within the web application.
Conclusion
For every organization, it’s best practice to perform an external and internal penetration test along with regular security audits to ensure the security of their IT system and determine what information can be exposed to the attackers.
It is also necessary because of IT security rules & regulations and guidelines like GLBA, FFIEC, NCUA, HIPAA, PCI, and other compliance standards.
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