Testing: Information Gathering
A security testing needs a first phase focused on collect of all the information about an application. Information Gathering is a necessary step of a penetration test.
This task can be carried out by using many different sources.
Using methods such as public tools (search engines), using fictitious requests purposely forged to receive error messages that give back the versions and technologies used by the application or analyzing and discovering the front-end/back-end infrastructure and applications with the purpose to collect many other useful information.
Often it’s possible to gather this information by receiving a response from the application because there are old and backup files or default bad configurations in the application server/web server.
Application discovery is an activity oriented towards the identification of the web applications hosted on a web server /application server.
This analysis is important because many times there isn't a direct link with the main application backend and for this reason a discovery analysis is useful to reveal details such as,web-apps used for administration, old versions of files or artifacts which were never deleted and created during the test/development phase or a result of maintainance.
This phase of the Information Gathering process consists in browsing and capturing resources relating to the application being tested. Browsers such as Google can be used to discover issues related to the web application strucutre or error pages produces by the application that can be found and is exposed to the public domain.
Web applications may divulge information during a penetration test which is not intended to be seen by an end user. Information (such as error codes)can inform the tester about technologies and products being used by the application. Such error codes can be easy to exploit without using any particular skill due to bad error handling strategy
Often an analysis on the infrastructure and topology architecture can reveal a lot of information about a web application such as source code, HTTP methods allowed, administration functionalities, authentication methods and infrastructural configurations.
For this reason focus only on the web application can't be an exhaustive test considering the information that it's possible to obtain during a security assessment by analyzing all the components present in a network.
During the configuration of a database server many DB administrators don't consider the importance of the security about DB Listener component which reveals sensible data as some kinds of configurations and database istances running.
The collection of these information can provide the needful elements to compromise the reservedness, integrity and availability of the data stored.
An accurate security analysis over DB listener configuration problematics permits to acquire these information.
The web applications hide some information which usally not cosidered during the development or the configuration.
These data can be discovered in the source code, in the log files or in default error codes of the web servers so a correct approach on this problematic is fundamental during a security assessment.
Observing the file extension present in a web server and so used for a web-app it's possible to comprehend the technologies which compose the applications (for example jsp and asp extensions in a server-side architecture) and the others systems linked to it.
The files contained in a web server (as old, backup and renamed files), freely readble and downloadble are a big source of information so it's necessary to verify the presence of these data because many times contain parts of source code, installation paths and sometimes also passwords for applications and/or databases.
OWASP Testing Guide v2
Here is the OWASP Testing Guide v2 Table of Contents