Open Source Security Testing Methodology Manual (OSSTMM)

The Open Source Security Testing Methodology Manual (OSSTMM) is a peer-reviewed methodology for conducting penetration testing and security assessments. It offers a comprehensive and structured approach to identify, exploit, and document vulnerabilities in computer systems and networks.

Here are some key characteristics of OSSTMM:

• Open Source: The methodology itself is freely available and not tied to a specific vendor or product.

• Focus on Process: OSSTMM emphasizes a structured testing process with clearly defined phases, activities, and deliverables.

• Multiple Channels: It considers various attack vectors, including network security, wireless security, physical security, and social engineering.

• Metrics and Measurement: OSSTMM incorporates methods for measuring the effectiveness of security controls and the overall attack surface of a system.

• Compliance Alignment: The methodology can be used to assess compliance with relevant security regulations and standards.

Benefits of using OSSTMM:

• Standardization: Provides a consistent framework for conducting pen tests, ensuring a repeatable and reliable process.

• Comprehensiveness: Addresses a broad range of security concerns, not just limited to network vulnerabilities.

• Customization: The methodology can be adapted to specific engagement needs and target environments.

• Transparency: The open-source nature promotes knowledge sharing and continuous improvement of the methodology.

Who uses OSSTMM?

• Penetration testers: Provides a structured approach to guide their testing activities.

• Security professionals: Helps assess the overall security posture of an organization.

• Organizations: Can use it to benchmark their security practices and identify areas for improvement.

Here's a comparison of OSSTMM with another popular methodology, PTES (Penetration Testing Execution Standard):

Feature	OSSTMM	PTES
Focus	Methodology for security testing	Standard for conducting pen tests
Scope	Broader, encompassing various security testing aspects	More specific to pen testing execution
Availability	Open-source and freely available	Paid standard developed by PCI SSC

The Open Source Security Testing Methodology Manual (OSSTMM) outlines a phased approach to penetration testing and security assessments. Here's a breakdown of the four key stages:

1. Induction Phase:

• Goal: Establish the foundation for the assessment by gathering information and defining the scope.

• Activities:

  • Review engagement contract and client requirements.

  • Conduct initial reconnaissance to understand the target environment (e.g., network topology, operating systems, applications).

  • Define the scope of the assessment, including authorized targets, attack methods, and exclusions.

  • Identify relevant security policies and procedures.

  • Obtain necessary legal permissions for testing activities.

2. Interaction Phase:

• Goal: Identify vulnerabilities and assess the security posture of the target systems and network.

• Activities:

  • Use various testing techniques like vulnerability scanning, social engineering, and manual exploitation to identify weaknesses.

  • Document discovered vulnerabilities, including details like exploitability and potential impact.

  • Assess the effectiveness of existing security controls in mitigating identified risks.

OSSTMM emphasizes five key testing channels during this phase:

* **Data Networks:** Focuses on network security assessments, including network scanning, service identification, and protocol analysis.
* **Human Security:** Evaluates the security awareness of personnel and their susceptibility to social engineering attacks.
* **Physical Security:** Assesses the physical security measures in place to protect systems and data (e.g., access controls, environmental controls).
* **Telecommunications:** Examines the security of telecommunication channels, including phone lines and network connections.
* **Wireless Security:** Evaluates the security of wireless networks, focusing on encryption strength and access control mechanisms.

3. Inquest Phase:

• Goal: Analyze the findings from the interaction phase and draw conclusions.

• Activities:

  • Evaluate the overall security posture of the target environment based on identified vulnerabilities.

  • Prioritize vulnerabilities based on their severity, exploitability, and potential impact.

  • Analyze the root causes of vulnerabilities to identify underlying weaknesses in security controls or processes.

  • Develop recommendations for remediation strategies to address the identified vulnerabilities.

4. Intervention Phase:

• Goal: Communicate the findings, recommendations, and next steps to the client.

• Activities:

  • Prepare a comprehensive report documenting the assessment methodology, findings, recommendations, and risk assessments.

  • Present the report to the client, explaining the vulnerabilities, their potential impact, and proposed remediation strategies.

  • Address any client questions or concerns.

  • Participate in a post-engagement review to discuss lessons learned and identify areas for improvement in future assessments.

Additional Considerations:

• The specific activities within each stage can be customized based on the engagement scope and client requirements.

• OSSTMM emphasizes the importance of documenting the entire process, from initial planning to reporting and post-engagement review.

By following these stages, penetration testers can conduct a thorough and structured security assessment, providing valuable insights into an organization's security posture and actionable recommendations for improvement.

Reference:

1. https://www.isecom.org/OSSTMM.3.pdf