Introduction

Before running w3af users need to know the basics about how the application works behind the scenes. This will enable users to be more efficient in the process of identifying and exploiting vulnerabilities.

Main plugin types

The framework has three main plugins types: crawl, audit and attack.

Crawl plugins

They have only one responsibility, finding new URLs, forms, and other injection points. A classic example of a discovery plugin is the web spider. This plugin takes a URL as input and returns one or more injection points.

When a user enables more than one plugin of this type, they are run in a loop: If plugin A finds a new URL in the first run, the w3af core will send that URL to plugin B. If plugin B then finds a new URL, it will be sent to plugin A. This process will go on until all plugins have run and no more information about the application can be found.

Audit plugins

Take the injection points found by crawl plugins and send specially crafted data to all in order to identify vulnerabilities. A classic example of an audit plugin is one that searches for SQL injection vulnerabilities by sending a'b"c to all injection points.

Attack plugins

Their objective is to exploit vulnerabilities found by audit plugins. They usually return a shell on the remote server, or a dump of remote tables in the case of SQL injection exploits.

Other plugins

Infrastructure

Identify information about the target system such as installed WAF (web application firewalls), operating system and HTTP daemon.

Grep

Analyze HTTP requests and responses which are sent by other plugins and identify vulnerabilities. For example, a grep plugin will find a comment in the HTML body that has the word “password” and generate a vulnerability.

Output

The way the framework and plugins communicate with the user. Output plugins save the data to a text, xml or html file. Debugging information is also sent to the output plugins and can be saved for analysis.

Messages sent to the output manager are sent to all enabled plugins, so if you have enabled text_file and xml_file output plugins, both will log any vulnerabilities found by an audit plugin.

Note

Ideas:
  • Send vulnerabilities to an internal issue tracker using its REST API
  • Parse w3af‘s XML output and use it as input for other tools

Mangle

Allow modification of requests and responses based on regular expressions, think “sed (stream editor) for the web”.

Bruteforce

Bruteforce logins found during the crawl phase.

Evasion

Evade simple intrusion detection rules by modifying the HTTP traffic generated by other plugins.

Scan configuration

After configuring the crawl and audit plugins, and setting the target URL the user starts the scan and waits for the vulnerabilities to appear in the user interface.

Any vulnerabilities which are found during the scan phase are stored in a knowledge base; which is used as the input for the attack plugins. Once the scan finishes the user will be able to execute the attack plugins on the identified vulnerabilities.

Configuration recommendations

At this point it should be obvious but:

Warning

Scan time will strongly depend on the number of crawl and audit plugins you enable.

In most cases we recommend running w3af with the following configuration:

  • crawl: web_spider
  • audit: Enable all
  • grep: Enable all