Penetration Testing

Black box vs. white box

Penetration tests can be conducted in several ways. The most common difference is the amount of knowledge of the implementation details of the system being tested that are available to the testers. Black box testing assumes no prior knowledge of the infrastructure to be tested, and the testers must first determine the location and extent of the systems before commencing their analysis. At the other end of the spectrum, white box testing provides the testers with complete knowledge of the infrastructure to be tested, often including network diagrams, source code and IP addressing information. There are also several variations in between, often known as gray box tests.

The relative merits of these approaches are debatable. It is argued that black box testing most closely simulates the actions of a real hacker, however this ignores the fact that any targeted attack on a system most probably requires some knowledge of the system, and any insider attacker would be in possession of as much information as the system owners. In most cases it is preferable to assume a worst-case scenario and provide the testers with as much information as they require, assuming that any determined attacker would already have acquired this.

In practice, the services offered by penetration testing firms range from a simple scan of an organisation's IP address space for open ports and identification banners to a full audit of source code for an application.

Rationale

A penetration test should be carried out on any computer system that is to be deployed in a hostile environment, in particular any Internet facing site, before it is deployed. This provides a level of practical assurance that any script kiddie or other more determined attacker will not be able to penetrate the system.

Methodology

The Open Source Security Testing Methodology Manual by Pete Herzog is a peer-reviewed methodology for performing penetration testing and obtaining security metrics. The OSSTMM covers the whole process of risk assessment involved in a penetration test, from initial requirements analysis to report generation. The six areas of testing methodology covered are:

Information Security
Process Security
Internet Technology Security
Communications Security
Wireless Security
Physical Security

The OSSTMM focuses on the technical details of exactly which items need to be tested, what to do before, during, and after a security test, and how to measure the results. New tests for international best practices, laws, regulations, and ethical concerns are regularly added and updated. The latest version of the manual is 2.1 with version 3.0 available soon.

The National Institute of Standards and Technology (NIST) discusses penetration testing in Special Publication 800-42, Guideline on Network Security Testing. NIST's methodology is less comprehensive than the OSSTMM however it is more likely to be accepted by regulatory agencies.

The fundamental concept for any penetration test is to simulate the attack vectors available to a malicious user.

Standards

If you are hiring a company to provide penetration testing services for you, it is important to be able to judge their abilities before engaging them. The process of carrying out a penetration test can reveal sensitive information and organisations must be certain they are dealing with professionals. It is for this reason that most security firms are at pains to show that they do not employ ex-hackers and that all employees adhere to a strict ethical code. In addition, there are several professional and government certifications that indicate the firms trustworthiness and conformance to industry best practice.

For example, ISECOM produces and hosts the OSSTMM methodology (see above) and will provide training and certification in its use. In the UK, CESG (the Communications-Electronics Security Group) has traditionally provided IT health check services for HMG and the public sector. It now maintains an accreditation for its IT Health Check Service, or CHECK. Companies belonging to CHECK must have employees that are security cleared and have passed the CESG Hacking Assault Course.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Penetration Testing".

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