🛡️ Internal Network Penetration Testing

📌 Introduction

Internal Network Penetration Testing is a security assessment performed from within an organization’s internal environment.
It simulates insider threats or attackers who have already gained access to the internal network, aiming to identify and exploit vulnerabilities.

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🎯 Objectives

• Assess security posture of internal systems and services.
• Identify misconfigurations, weak credentials, and unpatched systems.
• Evaluate exposure to insider threats.
• Test effectiveness of internal monitoring and defenses.
• Provide actionable remediation recommendations.

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🔍 Methodology (Step-by-Step)

1. Footprinting – Identify active hosts and devices.
2. Network Scanning – Scan IPs, open ports, and running services.
3. OS & Service Fingerprinting – Detect OS and versions.
4. Enumeration – Extract detailed system and service information.
5. Vulnerability Assessment – Identify and map vulnerabilities.
6. Exploitation – Attempt to exploit identified weaknesses.
7. Privilege Escalation – Gain higher-level access on compromised systems.
8. Post-Exploitation – Persistence, data exfiltration, and lateral movement.
9. Reporting – Document findings, severity, and mitigation.

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⚔️ Key Attack Vectors in Internal Testing

• Weak or default passwords.
• Unpatched systems and applications.
• Misconfigured network services.
• SMB, RDP, FTP, and SNMP exploitation.
• DNS poisoning and MITM attacks.
• Session hijacking and credential theft.

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🧰 Tools Commonly Used

• Nmap / Zenmap – Network scanning & fingerprinting
• Wireshark – Packet capturing & analysis
• Hydra / Medusa – Password brute force attacks
• CrackMapExec – Post-exploitation and lateral movement
• Responder – LLMNR, NBT-NS poisoning
• Metasploit Framework – Exploitation and privilege escalation
• Mimikatz – Credential extraction
• Netcat – Remote connections and backdoors

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✅ Best Practices for Internal Pentesting

• Define a clear scope with the client.
• Perform in a controlled environment.
• Maintain logs of activities.
• Respect data sensitivity (avoid unnecessary damage).
• Always provide remediation and defensive recommendations.

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📄 Reporting Deliverables

• Executive summary (non-technical).
• Technical findings with proof-of-concept.
• Risk ratings and CVSS scores.
• Exploitation steps and screenshots.
• Mitigation and hardening recommendations.

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🛡️ Defensive Countermeasures to Expect

• Network segmentation and VLANs.
• IDS/IPS (Intrusion Detection/Prevention Systems).
• SIEM monitoring (Splunk, ELK).
• Endpoint Detection & Response (EDR).
• Strong patch management and hardening policies.
• Principle of Least Privilege (PoLP).

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🧪 Practical Hands-On Steps

Step-1: Footprinting

• Identify hosts using ping sweep, ARP scan, or Nmap.

Step-2: Network Scanning

• Scan single IPs, multiple IPs, or entire subnets for open ports.

Step-3: OS & Service Fingerprinting

• Detect OS versions and services running.

Step-4: Enumeration

• NetBIOS, SMB, SMTP, SNMP, Telnet, HTTP enumeration.
• Capture traffic with sniffers.

Step-5: Vulnerability Assessment

• Scan with Nmap scripts, Nessus, or OpenVAS.

Step-6: Exploitation

• Attempt MAC flooding, DNS poisoning, MITM, brute-forcing, etc.

Step-7: Post-Exploitation

• Extract password hashes, escalate privileges, reset accounts.
• Plant keyloggers, spyware, trojans, or backdoors.
• Perform data exfiltration or persistence methods.

Step-8: Cleanup

• Reset target to original state.
• Remove created accounts, malware, and logs.

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⚠️ Disclaimer

This repository is for educational and authorized penetration testing only.
Performing internal penetration testing without permission is illegal and may cause severe consequences.
Always conduct assessments in a controlled lab or with written authorization.

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