Conducting an advanced penetration test on a corporate network involves a series of systematic steps designed to identify and exploit vulnerabilities, measure the level of security, and assess the effectiveness of defenses. Penetration testing should be done carefully and ethically, with permissions and defined scope, to avoid unintended disruptions or legal issues.

Pre-Engagement and Planning

• Define the Scope of Engagement: Clearly outline the boundaries of the test. Define the IP ranges, systems, and network segments that are in scope.
• Get Legal Authorization: Ensure you have written consent from the company’s senior management to perform the penetration test.
• Engagement Rules: Agree on rules of engagement which may include testing windows, outage allowances, and critical systems that should not be tested.
• Gather Intelligence: Collect as much information as possible about the target environment through public records, social media, and other open-source intelligence (OSINT).

Reconnaissance

• Passive Information Gathering: Perform non-intrusive gathering of information to avoid detection, using tools like Shodan, search engines, DNS reconnaissance, and social media platforms.
• Active Information Gathering: Conduct DNS enumeration, network scanning, and service identification with tools like Nmap and Nessus, always cautious not to cause disruptions.
• Identify Targets: Based on the gathered information, identify potential targets such as outdated software, misconfigurations, and exposed services.

Threat Modeling and Vulnerability Assessment

• Threat Modeling: Analyze the potential threat actors and their capabilities, intentions, and goals in context with the business.
• Vulnerability Scanning: Use automated tools like OpenVAS, Nexpose, or Qualys to find known vulnerabilities in the specified targets.
• Manual Identification: Manually inspect configurations and architecture designs to pinpoint weaknesses that automated tools may overlook.
• Verification and Prioritization: Verify the findings and prioritize the vulnerabilities based on their severity, impact, and exploitability.

Exploitation

• Develop Exploit Strategy: Based on the vulnerabilities identified and prioritized, craft an approach to exploit these weaknesses.
  • Ensure your methods align with the agreed rules of engagement.
• Tooling: Choose appropriate tools and write or customize exploits to match the target systems. Tools like Metasploit, Burp Suite, and custom scripts are commonly used.
• Gain Access: Execute the planned exploits to compromise systems, gain unauthorized access, or escalate privileges while minimizing disturbances.
• Maintain Documented Evidence: Keep a record of each step taken and evidence of successful exploits which will be crucial for the report.

Post-Exploitation

• Explore the Network: With the gained access, explore the network to understand the level of access obtained and to find more targets.
• Data Exfiltration Testing: Test the ability to remove data from the network undetected, simulating an attacker’s actions.
• Persistence: In some tests, establish ways to maintain access through backdoors or other methods, but only if within the agreed rules.

Analysis and Reporting

• Data Analysis: Analyze the data obtained from the exploitation phase to understand the security gaps.
• Risk Assessment: Assess the risks associated with each vulnerability exploited and potential business impacts.
• Compile the Report: Create a detailed report documenting:
  • Methodology
  • Findings
  • Exploited vulnerabilities
  • Evidence of exploitation
  • Business impact analysis
  • Recommendations for mitigation and security improvements.

Debrief and Knowledge Transfer

• Present Findings: Conduct a meeting with the stakeholders to present the findings and discuss the risks and recommendations.
• Transfer Knowledge: Ensure that the in-house security team understands the vulnerabilities, the means of exploitation, and the recommended countermeasures.

Remediation and Retest

• Support Remediation Efforts: Assist the organization in addressing the highlighted issues by providing technical guidance on the remediation steps.
• Validation Testing: Once the organization has patched the vulnerabilities, perform a retest to ensure that the changes have mitigated the risks effectively.

Continuous Improvement

• Lessons Learned: Evaluate the penetration testing process to identify improvements for future tests.
• Security Posture Enhancement: Work with the organization to implement a strategy for continuous monitoring and improvement of their security posture.