IT Center Blog

SQL Injection: Databases Attacks

March 23rd, 2022 | by
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Database systems are essential in many aspects. They allow large amounts of data to be organized, read and stored for the long term. The field of application of database systems is vast and so is the amount of personal data stored in them. For example, banks and insurance companies use databases to structure and store account information and information relating to accounting transactions. Every time we search for a product in a web store, we access a specific database, and our user data, such as login information, is also stored in databases. At best, these sensitive data are encrypted. The effort required to build and maintain these electronic databases is great – but the biggest challenge is to ensure their security. One of the greatest threats to these databases and the data they contain are so-called code injections.

What is Code Injection?

In simple terms, code injection is the insertion of malicious code into software which negatively affects the functioning of that application. This code introduced into the software can disrupt the security, integrity, and functionality of the application.

One of the best-known forms of code injection is so-called SQL injection (SQLI), in which the input is made via the SQL (=Structured Query Language) language. SQL has become the standard language used for database management. Database entries can be entered, read and deleted via so-called SQL queries. For example, if a website accesses its database to find or edit information, SQL is used to process this query. In practice, this can happen as follows: Users visit a web store. They communicate with a server using a product search mask in this web store. The server then queries a database and ultimately returns the results as search results to the web store.

This is exactly how databases can be vulnerable to code injections. Instead of entering a conventional search term in the input field, attackers enter SQL commands.

How does SQL Injection work?

Many websites gather user input via input fields in the web interface and forward it to their servers. This happens, for example, when users use a search field on a website, register, enter profile information or their e-mail address in a field. Comment fields, web form fields, or customer review fields are also such input fields. Hackers might try to enter various SQL codes into these input fields and attempt to penetrate the website’s database using this method. Specific examples show how SQLI can be used to create superusers and read or reset passwords, for example.

Any application that does not validate these inputs is vulnerable to code injection. Without validation, SQL code could be passed directly as a command and injected into the actual code. Once injected, this code could affect the commands executed by the system. For example, it would be possible to read, modify, or delete information without further authorization.

What are the Impacts of SQL Injection?

Injection attacks target servers and applications with free access for any Internet user. This makes companies and organizations in particular a prime target for cybercriminals. For affected companies and organizations, a wide range of threats can be identified. In many SQLI attacks, data is stolen. This data can include not only customer information, but also corporate secrets or intellectual property. In some cases, this data can then even be used to infiltrate other areas of the IT infrastructure.

Altering or deleting data in a database can also cause a lot of chaos and easily destabilize a company or organization. Image damage for companies and organizations should also not be underestimated. Once security breaches and personal data are made public, it can be very difficult to regain the trust of customers and the public.

The impact of such an attack can also have serious repercussions for private individuals. If users use a website that has been the target of such an attack, their personal data is no longer safe. In the worst case, data theft can lead to financial damage and identity theft for those affected.

How can Code Injections be prevented?

Since injection attacks target servers and applications, users themselves cannot prevent these attacks. As a general rule, users should be sparing and careful when sharing personal data on the Internet. The more data we disclose on the Internet, the more vulnerable we become. First and foremost, application developers should be aware of the risks and protect their applications accordingly. Every developer or server administrator should regularly check their systems for vulnerabilities and correct them as quickly as possible.

Ideally, every input into the web interface should be validated by the system and cleaned up if necessary. Special measures can be taken to ensure that inputs are not taken over as commands. This means, for example, that special characters that indicate manipulation are blocked. The allowed inputs can also be checked for their format and length and narrowed down. If the format of the input is too similar to the format of an SQL command, the input will not be forwarded. Also the amount of allowed characters can be limited. A well-known example of this are input fields for user names, where the use of certain special characters is restricted. One of the reasons for this is that these special characters have special functions in SQL.

Code injections can cause a lot of trouble. If an application is not sufficiently protected against injection attacks, these attacks can run in a completely automated way. Every single input field of an application can be scanned and tested for vulnerabilities by cybercriminals. If the attack is successful, the consequences can be severe. Unfortunately, users are powerless against SQLI attacks. Application developers should always be aware of the threat of SQLI attacks and protect their systems from attacks. Scans and vulnerability assessments are also essential as a preventive measure. This allows vulnerabilities to be detected and fixed immediately.


Responsible for the content of this article is Stéphanie Bauens.

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