This section describes the OWASP web application security testing methodology and explains how to test for evidence of vulnerabilities within the application due to deficiencies with identified security controls.
A security test is a method of evaluating the security of a computer system or network by methodically validating and verifying the effectiveness of application security controls. A web application security test focuses only on evaluating the security of a web application. The process involves an active analysis of the application for any weaknesses, technical flaws, or vulnerabilities. Any security issues that are found will be presented to the system owner, together with an assessment of the impact, a proposal for mitigation or a technical solution.
A vulnerability is a flaw or weakness in a system's design, implementation, operation or management that could be exploited to compromise the system's security objectives.
A threat is anything (a malicious external attacker, an internal user, a system instability, etc) that may harm the assets owned by an application (resources of value, such as the data in a database or in the file system) by exploiting a vulnerability.
A test is an action to demonstrate that an application meets the security requirements of its stakeholders.
The OWASP approach is open and collaborative:
This approach tends to create a defined Testing Methodology that will be:
The problems to be addressed are fully documented and tested. It is important to use a method to test all known vulnerabilities and document all the security test activities.
Security testing will never be an exact science where a complete list of all possible issues that should be tested can be defined. Indeed, security testing is only an appropriate technique for testing the security of web applications under certain circumstances. The goal of this project is to collect all the possible testing techniques, explain these techniques, and keep the guide updated. The OWASP Web Application Security Testing method is based on the black box approach. The tester knows nothing or has very little information about the application to be tested.
The testing model consists of:
The test is divided into 2 phases:
In the passive mode the tester tries to understand the application's logic and plays with the application. Tools can be used for information gathering.For example, an HTTP proxy can be used to observe all the HTTP requests and responses. At the end of this phase, the tester should understand all the access points (''gates'') of the application (e.g., HTTP headers, parameters, and cookies). The Information Gathering section explains how to perform a passive mode test.
For example the tester could find the following:
This may indicate an authentication form where the application requests a username and a password.
The following parameters represent two access points (gates) to the application:
In this case, the application shows two gates (parameters a and b). All the gates found in this phase represent a point of testing. A spreadsheet with the directory tree of the application and all the access points would be useful for the second phase.
In this phase the tester begins to test using the methodology described in the follow sections.
The set of active tests have been split into 11 sub-categories for a total of 91 controls: