Web applications are everywhere. You use them for banking, shopping, and social media. But they’re also a major target for hackers. A lot of the time, the attacks aren’t coming from a fancy network hack. They’re coming from a very simple concept: the web app’s failure to properly handle user input.
You can’t trust what a user puts into a form field. An attacker can use that input to gain access to a database, run malicious code on a user’s browser, or even take over a server.
The Most Common Web App Attacks
- SQL Injection (SQLi): This is a very common attack. A hacker puts a piece of SQL code into a form field. If the web app isn’t configured correctly, it will run that code on its database. The attacker can use this to get a list of all the users in the database, steal all the data, or even delete the entire database.
- Cross-Site Scripting (XSS): This is a client-side attack. An attacker injects a piece of malicious code into a web page. When another user visits that page, the code runs in their browser. The attacker can use this to steal a user’s session cookies, hijack their account, or even log their keystrokes.
- Cross-Site Request Forgery (CSRF): This attack tricks a user into performing an action they didn’t intend to do. For example, a hacker can send a user a malicious link. When the user clicks the link, it can send a request to a web app that they’re already logged into and perform an action on their behalf, like changing their password or making a purchase.
- Broken Authentication: This is when a web app has a flaw in its login or session management. An attacker can use this to take over a user’s account without having their password.
How to Build a More Secure Web App
- Input Validation: You need to validate and sanitize all user input. You can’t just trust that a user is going to type in a name. You have to check that the input is in the correct format and doesn’t contain any malicious code.
- Web Application Firewalls (WAFs): A WAF is a firewall that’s specifically designed to protect web applications. It can block a lot of these attacks before they even get to your application.
- Secure Coding: Developers need to be trained on how to write secure code. They need to know about these attacks and how to defend against them.
Web applications are a huge attack vector. A secure web app starts with the assumption that the user can’t be trusted. You have to build your defenses to handle the worst-case scenario.