Book Image

Web Penetration Testing with Kali Linux - Third Edition

By : Gilberto Najera-Gutierrez, Juned Ahmed Ansari
Book Image

Web Penetration Testing with Kali Linux - Third Edition

By: Gilberto Najera-Gutierrez, Juned Ahmed Ansari

Overview of this book

Web Penetration Testing with Kali Linux - Third Edition shows you how to set up a lab, helps you understand the nature and mechanics of attacking websites, and explains classical attacks in great depth. This edition is heavily updated for the latest Kali Linux changes and the most recent attacks. Kali Linux shines when it comes to client-side attacks and fuzzing in particular. From the start of the book, you'll be given a thorough grounding in the concepts of hacking and penetration testing, and you'll see the tools used in Kali Linux that relate to web application hacking. You'll gain a deep understanding of classicalSQL, command-injection flaws, and the many ways to exploit these flaws. Web penetration testing also needs a general overview of client-side attacks, which is rounded out by a long discussion of scripting and input validation flaws. There is also an important chapter on cryptographic implementation flaws, where we discuss the most recent problems with cryptographic layers in the networking stack. The importance of these attacks cannot be overstated, and defending against them is relevant to most internet users and, of course, penetration testers. At the end of the book, you'll use an automated technique called fuzzing to identify flaws in a web application. Finally, you'll gain an understanding of web application vulnerabilities and the ways they can be exploited using the tools in Kali Linux.
Table of Contents (19 chapters)
Title Page
Copyright and Credits
Packt Upsell

Mitigation and prevention of injection vulnerabilities

The key aspect of preventing injection vulnerabilities is validation. The user-provided input should never be trusted and should always be validated and rejected or sanitized if it contains invalid or dangerous characters such as the following:

  • Quotes (' and ")
  • Parentheses and brackets
  • Reserved special characters ('!', '%', '&', and ';')
  • Comments combinations ('--', '/*', '*/', '#', and '(:', ':)')
  • Other characters specific to language and implementation

The recommended approach for validation is the whitelist. This means having a list of allowed characters for each input field or group of fields and comparing the submitted strings to that list. All characters in the submitted string must be in the allowed list for it to be validated.

For SQL injection prevention, parameterized or prepared statements should be used instead of concatenating inputs to query strings. The implementation of prepared statements varies from one language to another...