The web application security industry is booming. As web applications have become an integral part of our everyday lives, so has the need to keep them secure. This article reviews web application security fundamentals and provides a guide for web application security testing tools. What is Web Application Security Testing? Web application security testing is the process of looking for vulnerabilities and security loopholes in websites or web applications. Potential security flaws could allow attackers to compromise the web application, which can lead to technical problems (i.e., transaction loss) or worse... data theft! Why is Web App Security Testing Important? There are many reasons why web security testing is important, here are some them: Companies need their websites and apps up 24\/24; if not, customers will find other viable options easily. If a website goes down because of an attack on its servers, this means big revenue losses every day it isn't running as intended. It is therefore essential web applications are kept secure.Security should be a priority for web applications, but unfortunately many web application development companies don't fully understand the importance of it or simply choose not to prioritize web app security testing. This can lead to data theft, which can decrease their reputation and cause them legal problems in the future. Is security testing for APIs and web services the same? APIs and web app security testing aren't the same thing \u2014 or are they? What are the differences between web services and API security testing, and what does each type of test try to achieve? APIs and web services are two different ways for apps to share data. API and web services testing, on the other hand, are two distinct tasks. How does Web Application Security Work? When you visit any website (e.g., Google), your browser requests information from that site's servers by sending an "IP packet" containing what you're looking for through multiple routers connected to different networks like ISP (Internet Service Providers) and WANs (Wide Area Networks). The router responsible for handling traffic to a specific domain name will then forward the request to the web server, which has a web application installed. Once the web application receives your request it will process and return information from its data stores (e.g., databases) via HTML pages that you can see in your browser. How do I Test My Web Apps? There are several ways to go about testing web application security, web app security testing tools are a great option for web developers. Web app pentesting tools can be used to find vulnerabilities in web apps and point out issues you may not have been aware of before. Types of Attacks on Web Applications Now that we've familiarize ourselves with how web apps work, let's take a look at some common types of attacks: XSS Attacks : Cross Site Scripting is an injection technique where malicious scripts are injected into legitimate sites or web applications in order to steal user information such as session cookies or login credentials when they visit these compromised websites using infected browsers. These types of vulnerabilities are very dangerous because attackers can launch them remotely by tricking users who visit web pages that have already been compromised.SQL Injection Attacks : These attacks are aimed at web applications' databases and consist of injecting malicious code (e.g., MySQL) to extract information from them, like user credentials or credit card details for example... which is obviously something you don't want happening!Session Fixation Attack: This attack allows an attacker to hijack valid sessions via session IDs cookies set by web servers after legitimate users log in to the web app. The intruder then takes over these hijacked sessions using his own username & password combination, allowing him access even though he may not be authorized on the system. Conclusion Web application security testing is a complex process, but web app testers can make it simple by keeping up-to-date with web app penetration testing industry trends and applying this knowledge to web applications they are responsible for. Web application security testing is a must if web applications are to be reliable and secure. New vulnerabilities such as cross-site scripting (XSS) and broken authentication appear every day so web app testers have their work cut out for them! However, web application security testing tools can help web app testers find flaws in web apps quickly and efficiently.