OSSTMM Penetration Testing Providers

Open Source Security Testing Methodology Manual · Published by ISECOM

The Open Source Security Testing Methodology Manual (OSSTMM) is a peer-reviewed methodology for performing security tests and metrics, developed and maintained by the Institute for Security and Open Methodologies (ISECOM). Unlike other testing frameworks that focus primarily on finding vulnerabilities, OSSTMM takes a scientific approach to security testing by measuring the actual attack surface and quantifying security through its Risk Assessment Values (RAV) scoring system.

OSSTMM version 3 defines five channels of security testing: Human Security, Physical Security, Wireless Communications, Telecommunications, and Data Networks. Each channel is tested for operational security, controls, and limitations using a consistent set of testing modules. The methodology's emphasis on measurable security outcomes rather than subjective risk ratings makes it particularly valuable for organisations that need to demonstrate security improvements over time or compare security posture across different systems and environments.

OSSTMM's comprehensive scope — covering physical, human, and technical dimensions — makes it well-suited for organisations seeking a holistic security assessment rather than purely technical testing. The methodology is freely available under a Creative Commons licence, and its structured approach to quantifying security helps organisations move beyond checkbox compliance toward genuine security improvement.

Key Features

  • Five-channel security testing model
  • RAV quantitative scoring system
  • Covers human and physical security
  • Scientific measurement approach
  • Peer-reviewed methodology

Best For

  • Holistic security assessments
  • Quantitative security measurement
  • Physical security testing
  • Telecommunications security
  • Security posture benchmarking

Providers using OSSTMM (6)

6 providers
Top UK ProviderElite TestersResearch-Driven
SECFORCE logo

SECFORCE

Leading UK offensive security consultancy based in Canary Wharf, delivering CREST-accredited penetration testing and adversary simulation to organisations with the most demanding security requirements.

95
Score
LOCLondon, United Kingdom
Web ApplicationNetworkMobile App+9
CRESTISO 27001Cyber Essentials
Best UK ProviderBest for EnterpriseResearch Leaders
NCC Group logo

NCC Group

Global cybersecurity consultancy with CREST, CHECK, and CBEST accreditation, renowned for deep technical research and comprehensive penetration testing services.

75
Score
LOCManchester, United Kingdom
Web ApplicationNetworkMobile App+13
CRESTCHECKCBEST+6
Best OverallElite TestersResearch Pioneers
Bishop Fox logo

Bishop Fox

Premier US-based offensive security firm known for elite penetration testers, cutting-edge research, and the Cosmos continuous attack surface management platform.

50
Score
LOCTempe, Arizona, United States
Web ApplicationNetworkMobile App+8
SOC 2OSCP Employer
SEC Consult logo

SEC Consult

Leading European cybersecurity consultancy from Vienna with a prolific vulnerability research program and deep expertise in IoT and embedded systems security.

43
Score
LOCVienna, Austria
Web ApplicationNetworkMobile App+7
ISO 27001
IOActive logo

IOActive

Elite boutique security consultancy specializing in IoT, SCADA/ICS, embedded systems, and hardware security research with world-renowned researchers.

42
Score
LOCSeattle, Washington, United States
Web ApplicationNetworkIoT+7
OSCP Employer
Offensive Security logo

Offensive Security

Creators of OSCP, Kali Linux, and Exploit-DB, offering elite penetration testing services from the team that trains the world's ethical hackers.

40
Score
LOCNew York, New York, United States
Web ApplicationNetworkRed Teaming+5
OSCP Employer

OSSTMM FAQs

What makes OSSTMM different from other methodologies?+

OSSTMM uniquely focuses on measuring security quantitatively through its RAV scoring system, rather than simply finding vulnerabilities. It also covers physical and human security channels alongside technical testing.

Is OSSTMM free to use?+

Yes, OSSTMM is available under a Creative Commons licence from ISECOM. The full methodology manual can be downloaded freely from their website.

What is the RAV score?+

The Risk Assessment Value (RAV) is OSSTMM's quantitative scoring system that measures the relationship between operational controls and the attack surface to produce a numerical security score, enabling objective comparison over time.