Testing: Information Gathering
The first phase in security assessment is focused on collecting all the information about a target application. Information Gathering is a necessary step of a penetration test.
This task can be carried out by using many different ways.
Using public tools (search engines), scanners, sending simple HTTP requests, or specially crafted requests, it is possible to force the application to leak information by sending back error messages, revealing the versions and technologies used by the application.
Often it is possible to gather information by receiving a response from the application which, as a consequence of bad default configuration of the application server or web server, could reveal vulnerabilities in the configuration or bad server management.
Application fingerprint is the first step of the Information Gathering process; knowing the version and type of a running web server allows testers to determine known vulnerabilities and the appropriate exploits to use during testing.
Application discovery is an activity oriented to the identification of the web applications hosted on a web server/application server.
This analysis is important because many times there is not a direct link connecting the main application backend so a discovery analysis would be useful to reveal details such as web-apps used for administrative purposes, old versions of files or artifacts (such as scripts not properly deleted after their usage while crafted during the test/development phase or as the result of maintenance).
This phase of the Information Gathering process consists of browsing and capturing resources related to the application being tested. Search engines, such as Google, can be used to discover issues related to the web application structure or error pages produced by the application that are usually found after being 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 analysis of the infrastructure and topology architecture can reveal a lot of information about a web application such as source code, HTTP methods permitted, administrative functionalities, authentication methods and infrastructural configurations.
For those reasons, focusing only on the web application will not be an exhaustive test, considering the fact that the information collected during the security assessment could not be as exhaustive as the information possibly gathered by performing a wider test comprehensible to an infrastructure analysis.
SSL and TLS are two protocols which provide, with the support of the cryptography, a secure channel for the communications to protect the confidentiality & authentication of the information and a secure channel.
Considering the importance of those security implementations it is important to verify the usage of a strong cipher algorithm and its proper implementation has been performed.
During the configuration of a database server, many DB administrators do not consider the importance around the lack of security of the DB Listener component. It could reveal sensible data as well as the configuration settings or database instances running.
The collection of this information could provide some useful hints needed to compromise the reservedness, integrity and availability of the data stored.
An accurate security analysis of the DB listener configuration can allow for the acquisition this information.
The web applications hide some information which is usually are not considered during the development or configuration of the application itself.
This data can be discovered in the source code, in the log files or in the default error codes of the web servers so a correct approach to this topic is fundamental during a security assessment.
By observing the file extensions present in a web server or a web-app, it is possible to identify the technologies which compose the target application (for example jsp and asp extensions in a server-side architecture) and sometimes additional systems connected to the application.
Redundant files which could be present on a web server (such as old, backup and renamed files), which remain freely readable and downloadable, are a big source of information leakage. It is necessary to verify the presence of these files because they may contain parts of source code, installation paths as well as passwords for applications and/or databases.
OWASP Testing Guide v2
Here is the OWASP Testing Guide v2 Table of Contents