The Open Source tool was implemented in Java and is thus available for a variety of platforms. It uses Java components from the Apache project, Mozilla's Rhino Javascript engine, and the database from the free Nikto scanner.

Grendel Scan can run as a proxy between the browser and the website under investigation to allow the tester to view and manipulate the HTTP traffic. The application covers a wide selection of tests including cross-site scripting (XSS), cross-site request forgery (CSRF), SQL injection, and session management vulnerabilities.

A Powerpoint presentation by the developers provides a useful overview of Grendel Scan's features.

Grendel Scan's makers, David Byrne and Eric Duprey, point to the fact that their software automates tests for trivial vulnerabilities as one of the major benefits. This helps qualified security staff to save time more usefully spent performing more complex manual tests. According to the developers, the tool does not remove the need for individual security tests and code reviews, which are still necessary to guarantee the security of any Web application. For example, a tool like Grendel Scan is unable to detect vulnerabilities in the application's logic or design.

There is no need to resolve any dependencies, apart from Java 5, for the GPLv3 licensed tool. The project's download page offers the Grendel Scan 1.0 source code along with builds for Linux, Windows, and Mac OS X. On top of this, there is a Slax-based live CD with the scanner and a flawed Web application for demonstration purposes. The ISO image still uses Grendel Scan version 0.9, however.