Web Application Attack: What Is It and How to Defend Against It?

Web application attacks are an increasing cybersecurity threat in the past couple of years. There are billions of recorded web application attacks in 2018 and 2019, and it is estimated that 46% of websites have security vulnerabilities at the application level. 

So, there’s a high likelihood that your website might be vulnerable to this type of attack, and this is why you must learn about web application attacks and what you can do to prevent it. 

Here, we will learn all you need to know about a web application attack and how to defend against it. Let us begin, however, by discussing the basic concept of web application attack. 

What is a Web Application Attack

To truly understand the concept of web application attack, we have to understand what is really meant by “web application”. 

In layman’s terms, a web application or web app is a program/software that runs on a web server and is accessed just like accessing a website. Most modern websites nowadays consist of two different aspects: a web browser and at least one web application. 

The web browser, as we know, is an app that allows users to interact with web pages and consume the content. The web applications, on the other hand, are computer programs allowing website visitors to submit and retrieve data via this web browser. 

A website can either use a brand new web application that is created from scratch, or it might be purchased from a third-party vendor. What’s important is that during a web application attack, the cybersecurity threat specifically targets this web app. 

Web Application Attack

A web application attack, as discussed, specifically targets the web app. The web application is often the bridge between the web servers and database servers. So, when a web application is compromised, both the web servers and database servers might also be compromised. 

More often than not, a web application attack is launched to target the database servers, which might contain valuable information (user’s banking information and personal data). 

A typical web application attack can be described as the following: 

• A perpetrator finds a vulnerability in the web application and sends an attack to the web server via port 80 (HTTP) and 443 (HTTPS)
• The web server receives the malicious packet but fails to detect is as an attack, so the server passes the packet to the web application server
• The web application server receives the malicious code from the web server, and again, fails to detect it as a malicious attack and sends it to the database server
• Finally, the malicious code is executed when it reaches the database server. The code, for example, instructs the database to returns data containing users’ financial information
• The web application server follows the instruction of the database server and generates a page containing the banking information from the database
• The web server then displays this page containing banking information to the attacker

However, web application attacks can come in various forms, and each of them might require different prevention methods. 

Common Types of Web Application Attacks and How To Prevent Them

1. Cross-Site Scripting (XSS)

Cross-site scripting or XSS is one of the most common types of web application attacks. In an XSS attack, the attacker hides malicious JavaScript in client-side codes. Whenever the web page is loaded, this JavaScript snippet is loaded. 

Preventing XSS: 

• Input validation: validate inputs coming from the web application to keep away untrusted snippets. We can blacklist known sources of attacks and only allow trusted websites or sources. 
• Sanitizing and escaping user input: sanitizing is modifying inputs from a web application to ensure it is valid while escaping is securing the data before passing it to the database server or web server. 

2. Local File Inclusion (LFI)

File inclusion is a technique to include scripts in server-side codes. Thus, LFI is used by the attacker to trick the web application to expose sensitive files on a web server. A successful LFI can be followed by a cross-site scripting and other web application attacks. 

LFI exploits the fact that when a web app uses a file path as an input, it is always treated as trusted. The LFI can then be injected via this file path when the code is vulnerable. 

Preventing LFI: 

• ID assignation: make sure to save your file paths in a secure database and ID every file path. So, users (and attackers) can only see the ID and can’t view the path
• Optimize server instruction: make sure the server can automatically send download headers instead of automatically executing files in a specified directory
• Whitelisting: only use the verified and whitelisted files 

3. Directory Traversal

Directory traversal or path traversal is when the attacker can gain access to the restricted directories on the web beyond the web root directory. The attacker can then launch other web application attacks by accessing system files, run OS commands, and so on. 

Preventing directory traversal: 

• The web application should always validate user input before processing any instruction
• After validating the input, the web application should append the input to the base directory and check the file path. The API should verify that the file path starts with the right base directory

Automated Application-Level DDoS

DDoS (Distributed Denial of Service) attack might be performed on a web application level and is mainly done by sending repetitive instructions with the help of bots and botnet. 

Prevention:

• A proper web application firewall, as well as CAPTCHA, might help in defending against basic bot activities. However, sophisticated bots, as well as the existence of CAPTCHA farm services might render these approaches useless 
• You can check web application security solutions and services by DataDome that also offers real-time bot detection solutions with behavior detection capabilities.

End Words

In today’s ever-evolving web application attacks, it’s increasingly important for every business and online entity to consider and adopt a clear protection strategy. Be proactive in figuring out the best approach in protecting your web application side, and make sure to always validate inputs coming from the web application server.

 A real-time bot detection solution can significantly help in defending against today’s sophisticated web application attacks and is a worthy investment if you are looking for ways to protect your system from incoming cybersecurity threats.