Metasploit Framework 3: the Ruby rewrite and the maturation of open source penetration testing

Metasploit Framework 3 (March 2007) by H.D. Moore: full rewrite in Ruby, modular architecture (exploit, payload, auxiliary, encoder), Meterpreter as in-memory payload. Version 3.2 and the state of the art of pentest at 2008.

Cyber SecurityOpen SourceR&D MetasploitPenetration TestingCyber SecurityRubyHD MooreOpen Source

The framework that standardises pentest

Metasploit Framework was started in 2003 by H.D. Moore in Perl as a structured collection of exploits and penetration testing support tools. The original version (1.x, 2.x) gained increasing use in the security research community, but its Perl architecture did not scale with the exploit and functionality growth pace. The strategic choice was to rewrite the entire framework from scratch in Ruby.

Metasploit Framework 3.0 was released in March 2007. The current version at time of writing is 3.2 (October 2008), with further UI and payload improvements.

The modular architecture

Metasploit 3 introduces a module taxonomy that will remain stable for decades:

  • Exploit — code exploiting a specific vulnerability to gain execution
  • Payload — code executed after the exploit (shell, Meterpreter, reverse connection, bind shell)
  • Encoder — transforms the payload to evade IDS/IPS filters (e.g. shikata_ga_nai)
  • Nopsno-operation instruction generators to make the exploit more resilient
  • Auxiliary — scanning, fuzzing, enumeration modules without necessarily exploiting vulnerabilities
  • Post — post-exploitation execution (privilege escalation, credential harvest, lateral movement)

Exploit/payload separation is the most important conceptual contribution: the same exploit can launch any compatible payload, the tester does not need to rewrite logic for each combination.

Meterpreter

One of the most relevant payloads introduced/matured in the 3.x branch is Meterpreter — payload dynamically loaded that lives in memory without writing to disk, reducing forensic traces. Meterpreter exposes a rich command-response API: filesystem, Windows registry, network, process injection, keylogging, webcam/microphone (where applicable), pivoting towards other networks through the compromised node.

Meterpreter being cross-platform (Windows, Linux, BSD) and extensible with dynamic modules makes it the de facto reference in offensive pentest for over a decade.

Interfaces

Metasploit 3 exposes:

  • msfconsole — interactive CLI, the most used interface, with history, autocompletion, tabbing
  • msfcli — shell script invocation for automation
  • msfweb — web interface (removed in later releases)
  • msfopcode — opcode database useful for building custom payloads

Integration with Nmap for discovery, PostgreSQL for information database during a campaign, and Ruby API for custom extensions, completes the framework as end-to-end platform.

Licence and distribution

Metasploit Framework is distributed under BSD licence (later evolved to Metasploit Framework License, a BSD-based variant). Code is fully open and the exploit base is community-contributed: security researchers publish exploits month after month, reviewed and integrated into the framework.

This model has dual valence: it accelerates exploit availability for defensive researchers and authorised pentesters, but also raises questions on publishing responsibility. The Metasploit community has developed a responsible disclosure ethic: exploits for vulnerabilities published with a delay relative to the vendor’s official patch.

Rapid7 acquisition

In October 2009 the Metasploit Project is acquired by Rapid7 — US security vendor already active with Nexpose for vulnerability management. H.D. Moore remains project CSO. The acquisition marks Metasploit’s shift to an open core model:

  • Metasploit Framework remains open source and free
  • Metasploit Express and Metasploit Pro — commercial versions with graphical interface, reporting, enterprise automation, workflows

This model funds continuous development of the open framework.

Legitimate use

Metasploit is a dual-use tool: usable in malicious attacks or in authorised defensive activities. Typical legitimate use:

  • Penetration tests authorised by written contract with the client
  • Red team internal to an organisation to simulate attacks
  • Training of security personnel (courses, CTF labs)
  • Security research on vulnerabilities before patching
  • Validation of defensive systems (SOC, IDS, EDR) against real scenarios

In Italy use of tools like Metasploit requires formal authorisation from the system’s legitimate owner; unauthorised use falls under the criminal offences of Article 615-ter of the Penal Code (unauthorised access to a computer system) and subsequent.

Competitors and complements

As of 2008 the pentest ecosystem includes:

  • Nessus (Tenable) — commercial vulnerability scanner (6.x), with a large control base
  • OpenVAS — open source fork of Nessus 2.x after Nessus 3.x went closed source (2005)
  • Burp Suite — web intercepting proxy (PortSwigger, Free/Pro)
  • Nmap — port scanner and network discovery (complementary, not competitor)
  • Canvas (Immunity) and Core Impact — commercial frameworks alternative to Metasploit

Metasploit stands out for open source completeness and extensibility.

In the Italian context

As of 2008 Metasploit is used in Italy by:

  • Cyber consulting firms specialised in pentest
  • CERTs and university research groups (Pisa, Milan Politecnico, Rome La Sapienza)
  • SOCs of large companies and public administration for internal testing
  • Italian communities — Italian Security Team, SikurWare, MOCA hackmeeting

Adoption will grow significantly in the next five years, alongside strengthening regulatory frameworks on cybersecurity (Legislative Decree 82/2005 CAD, subsequent Legislative Decree 65/2018 transposing NIS1, then 2022/2024 NIS2).


References: Metasploit Framework 3.x (March 2007 - October 2008), H.D. Moore. BSD-based licence. Rapid7 (acquisition October 2009). Meterpreter payload. Ruby as implementation language. Nmap, PostgreSQL integration.

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