An Introduction To SQL Injection

In this lesson, we will introduce you to the SQL injection, its issues impact and of course teach you how to fix it. Besides that, we will take a look how such attacks seems like and also the examples of the issue, because in that case, you will be better introduced to it in total. You will know how to recognize it once it appears, or even better-to prevent it! Let’s see what we need to know about this issue!

SQL Injection Description

This issue could be best described as a type of the security exploit that the attacker can add to the Structured Query Language. That is why it is called SQL. The attacker actually adds injects sql code on to a Web form input’s box. Once he or she does such an action, it is available for that person to gain the access to the resources or even to make some changes to the data.


What is a SQL query? I can explain you this term the best if you try to understand it as a request which is sent to the server which needs to be performed on the targeted database. Most of the times it happens this way-let’s say the user has entered its name and also a password on a Web form for its authentication. The user used his personal information with a purpose to gain the access through the text boxes. What happens then is that those values are inserted automatically into a SELECTION query section. So, it is logical that if they fit, the access is gained, and if not, it is denied.

But, it is not all that simple. Many of the Web forms don’t have the mechanisms in place to have the power to block the input other than the names and passwords. It is obvious that if the precautions are not taken, the attacker will easily use those text boxes and then send its own request to the wanted database. It will allow him/her to download the whole database and also to interact with it in various illicit ways.



SQL Injection Impact

As you can easily understand the description of this issue, its main goal is to have the impact of the database’s security. Those attacks are also known under a name SQLIA and can be easily detected in a great amount of the web apps which lack the input’s variable filtering. There have been so many web developers who neglected the strength of the SQL injection attacks and haven’t protected the apps in a proper way. That encouraged the attackers to ruin the security and also the confidentiality of the data stored in a database. The malicious injection easily passes to those and then the server may damage the total database or the data which has been stolen. So, with a SQL the attacker is able to:

  • use it with a purpose to bypass the authentication or to impersonate some targeted users;
  • to select the data which is based on a query and to get the output results of it;
  • use it to alter the data which is stored in the database and in that case to affect the integrity causing the repudiation issues;
  • for deleting targeted records from the database;
  • for allowing the arbitrary execution on the database’s server.


Example Of SQL Injection

We will now show how this issue looks like in the example. I will show you the normal requests to the same data, and later how to recognize the difference when the SQL injection appears. So, let’s see and recognize the difference! Stay concentrated!

The first example I will show now is the normal HTTP request which some legitimate user would send.



Does this request look normal to you? At the first sight, but, the artist parameter here which is located in the GET’s request query string is actually vulnerable to the SQL injection. That is because the value of the string is -1.

So, the injected query then joins to the result which is coming to the original query and allows the attacker to exfiltrate the data from the database.



If you understood that it wasn’t the safe request from the first example! If not, now you know how to recognize it!

Recent Attacks Of SQL Injection And Impact

The risk of these exploits is on the rise. It isn’t surprising because of so many automated tools which we have more and more. The recent attacks are happening in a way through the SQL automated programs. Such technology has been publicly released. Logically, it was done by some black hat. It gives the script-kiddies the possibility to pick a freeware tool and then it is easy to download the whole database without any knowledge needed.


How To Fix SQL Injection

We will now learn how to prevent such an issue to happen or how to fix it. First of all, before you want to process the SQL query, you need to be sure that user’s input is validated. Those SQL queries that have the user input need to be dealt with by using the parameterized queries. With it, you will be able to recognize where the SQL injection lays and then to solve it. It is also very important to remember that you should never display the SQL errors to the users. If you need to do it, always use a generic error message, because it won’t relieve any of the sensitive information. And the last thing, be sure that you are using the stored procedures in a safe manner.

Hope that you have enjoyed this article and also that you have learned so much from it! We met you with the SQL injection in total. Now, when you understand, you can also know how to fight against it!

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