SQL Injection – Fundamentals

26

September, 2022

Days 55 – 57
SQL Injection – Fundamentals
100 Days of Hacking

Photo Cred –> Caspar_Rubin

SQL Injections

In this Days of Hacking session, we covered SQL and SQL Injections.

To learn more about the subject in depth, please have a look at the following – HTB’s Bug Bounty Hunter Job Role Path

Here’s a summary of what was covered:

 

  • Basics of databases and their different types
  • Basics of SQL and MySQL
  • Basic statements and operators in MySQL and how to use them
  • What are SQL injections, and how can we use them
  • Use SQL injections to subvert the web application logic and bypass authentication
  • Use UNION SQL injections to dump data from different tables and databases within the DMBS
  • Use SQL injections to read files of the back-end server
  • Use SQL injections to write a web shell on the back-end server and gain remote control over it
  • How to mitigate such SQL injections and patch your code

Subverting Query Logic

Here we were to try logging in as the user ‘tom’ and obtaining the flag value.

flat screen computer monitor displaying white and black screen
flat screen computer monitor displaying white and black screen

Day 56

Using comments

Here we were to login as the user with the id 5 to get the flag.

flat screen computer monitor displaying white and black screen

Day 57

Database Enumeration

Here we were to find the password hash for ‘newuser’ stored in the ‘users’ table in the ‘ilfreight’ database?

Reading Files

We see in the above PHP code that ‘$conn’ is not defined, so it must be imported using the PHP include command. Check the imported page to obtain the database password.

Writing Files

Here we were to find the flag by using a webshell.

Now that we’ve covered the basics of SQL and know what SQL Injections are, how to find and exploit them, next we’ll look at tool that can help us automate some of the heavy lifting.

As always thanks for reading if you’ve made it this far. You’re sincerely appreciated.

Hack On, Ladz & Gentz!

Many people who have been called hackers, especially by the media, or who have gotten in trouble for “hacking” were not, in fact, hackers. – Lesson 1: Being a Hacker

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