How to Conduct a Penetration Test on a Corporate Network

November 28, 20234 min read

Conducting a penetration test on a corporate network is a systematic process aimed at identifying and exploiting security vulnerabilities. Below are detailed steps spread across several key phases:

Phase 1: Planning and Preparation

Define the Scope

  • Determine Target Systems: Agree on which network elements are to be tested (servers, applications, devices, etc.).
  • Establish Boundaries: Specify the limits of the penetration test, such as no disruption to production systems.

Legal and Regulatory Compliance

  • Authorization: Obtain written permission to perform the penetration test to avoid legal repercussions.
  • Compliance Standards: Understand and adhere to applicable laws and industry standards such as GDPR, HIPAA, or PCI-DSS.

Information Gathering

  • Open Source Intelligence (OSINT): Collect publicly available information to map the target organization’s digital footprint.
  • Technical Reconnaissance: Identify the network range, domain names, and IP addresses of the target.

Phase 2: Reconnaissance

Passive Reconnaissance

  • Non-intrusive Techniques: Gather information using tools like SHODAN, Censys, or passive DNS analysis without directly interacting with the target’s network.

Active Reconnaissance

  • Direct Interaction: Use network scanning tools like Nmap to discover devices, services, or open ports on the network.

Phase 3: Vulnerability Assessment

Network and Service Scanning

  • Network Mapping: Identify live systems and open ports.
  • Service Identification: Determine the versions and configurations of running services to map potential vulnerabilities.

Vulnerability Scanning

  • Automated Scans: Use tools such as Nessus, OpenVAS, or Qualys to identify known vulnerabilities.
  • Manual Validation: Verify identified vulnerabilities to ensure accuracy and reduce false positives.

Phase 4: Exploitation

Exploiting Vulnerabilities

  • Leveragate Tools: Employ automated exploitation tools like Metasploit or manual techniques to compromise vulnerable systems.
  • Document Exploitation: Maintain detailed records of all exploited vulnerabilities and the associated risks.

Credential Assessment

  • Credential Harvesting: Attempt to acquire credentials via methods like dumping password hashes, phishing, or keylogging.

Lateral Movement and Privilege Escalation

  • Access Expansion: Attempt to move laterally within the network to identify more systems and data.
  • Elevate Privileges: Try to gain higher-level access to systems and the network.

Phase 5: Post-Exploitation

Establishing Persistence

  • Maintain Access: Use methods like adding accounts or deploying backdoors for continued access.

Data Harvesting

  • Sensitive Data Identification: Locate and potentially exfiltrate sensitive data to demonstrate risk.

Phase 6: Analysis and Reporting

Data Analysis

  • Vulnerability Categorization: Arrange the vulnerabilities in terms of risk, impact, and ease of exploitation.


  • Comprehensive Report: Draft a report outlining vulnerabilities, exploits, compromised systems, and sensitive data accessed.
  • Risk Analysis: Include an assessment of the potential business and operational impacts.


  • Remediation Strategies: Provide a timeline and methodology for remediating vulnerabilities.


  • Stakeholder Meeting: Present findings and discuss the implications with stakeholders.

Phase 7: Cleanup

Removing Access

  • Reversal of Changes: Remove any backdoors, accounts, or tools introduced during testing.

Phase 8: Retest

Verify Fixes

  • Re-Examine: After remediation efforts, re-test systems to confirm that vulnerabilities are properly fixed.

Throughout all phases, it’s critical to maintain a clear line of communication with the client, adhere strictly to the scoped boundaries, meticulously document all findings and actions, and operate within the legal and ethical confines of the cybersecurity industry.