Cross Site Scripting: Definition, Examples


Cross Site Scripting, often abbreviated as XSS, is a type of security vulnerability typically found in web applications. It allows attackers to inject malicious scripts into websites viewed by other users. These attacks can lead to a variety of problems, including identity theft, data theft, and defacement of websites.


The phonetic pronunciation of “Cross Site Scripting” is: Kross Syt Skrip-ting.

Key Takeaways

Cross Site Scripting Takeaways

Main Takeaways about Cross Site Scripting

  1. Cross Site Scripting (XSS) is a type of security vulnerability typically found in web applications. It enables attackers to inject malicious scripts into web pages viewed by other users.
  2. XSS vulnerabilities can have serious implications including theft of session cookies, defacement of websites, or redirecting the user to malicious sites.
  3. Best practices to prevent XSS include validating, sanitizing, and escaping user input, implementing Content Security Policy (CSP), and using secure coding practices like parameterized queries and encoding data.


Cross Site Scripting (XSS) is a significant term in the realm of technology as it refers to a prevalent type of security vulnerability in web applications. XSS allows attackers to inject malicious scripts into web pages viewed by other users, potentially compromising their data. This form of a security loophole is seen frequently in applications that use user input to generate output without proper validation and encoding. Understanding XSS is crucial for both developers and users since it heightens awareness about implementing secure coding practices and ensuring robust cybersecurity measures, respectively. It’s a vital step towards creating safer digital environments and protecting valuable data from potential threats.


Cross-Site Scripting, commonly referred to as XSS, is a type of security vulnerability that primarily affects web applications. The main purpose of utilizing Cross-Site Scripting techniques is for attackers to inject malicious scripts into websites or web applications that are viewed by other users. By exploiting these security loopholes, hackers can bypass access controls and manipulate the behaviors of web browsers to desired effect.From a malicious actor’s perspective, XSS is used to steal sensitive data, such as login credentials, manipulate web content, or distribute malware to unsuspecting users. These actions are often achieved by tricking a victim’s browser into executing a script that appears to be originating from a trusted site. While it poses significant security risks, understanding and rectifying XSS vulnerabilities is part of ensuring robust web application security.


1. MySpace Worm: Probably the most famous example of Cross-Site Scripting (XSS) was the MySpace Worm in 2005. A coder by the name of Samy Kamkar created a self-replicating XSS worm that added him as a friend and displayed a message saying, “Samy is my hero.” Within 24 hours, Samy was added to over a million profiles and MySpace had to temporarily shut down to stop the spread of the worm. 2. TweetDeck XSS Attack: In 2014, TweetDeck, a popular social media dashboard application for management of Twitter accounts, was hit by an XSS attack. An attacker was able to exploit an XSS vulnerability to execute arbitrary JavaScript code on the user’s browser making thousands of pop-up alerts appear on people’s screens.3. Yahoo Mail XSS Vulnerability: In 2013, an XSS vulnerability was discovered in Yahoo Mail which could be exploited by attackers to read the victim’s emails or inject malicious code into their browser. The vulnerability was subsequently patched by Yahoo after it was disclosed.

Frequently Asked Questions(FAQ)

**Q1: What is Cross Site Scripting?**A1: Cross Site Scripting (XSS) is a type of security vulnerability typically found in web applications. XSS attacks enable attackers to inject client-side scripts into web pages viewed by other users, which could lead to various types of harmful activities such as stealing user data, credentials, or altering the website content.**Q2: What are the different types of Cross-Site Scripting?**A2: There are primarily three types of XSS attacks: Stored (or Persistent) XSS, Reflected XSS, and DOM (Document Object Model)-based XSS.**Q3: What is the difference between Stored XSS and Reflected XSS?**A3: In a Stored XSS attack, the malicious script is stored on the server and then run when the user accesses the website. In contrast, a Reflected XSS attack involves the malicious script being part of the website’s request, and it only affects the users who open the malicious link.**Q4: How can Cross-Site Scripting be prevented?**A4: One common tactic for preventing XSS attacks is by sanitizing user input, which essentially involves disallowing or filtering out potentially harmful data. Additionally, encoding user input and employing Content Security Policy (CSP) are other effective strategies for combating XSS attacks.**Q5: What is the impact of Cross-Site Scripting attacks?**A5: The consequences of XSS attacks can be quite serious. They can lead to the theft of login credentials and personal information, defacement of web pages, distribution of malware, and many other malicious activities.**Q6: Can Cross-Site Scripting attacks be detected and reported?**A6: Yes, XSS attacks can often be identified by unusual activity on the website, such as unexpected pop-ups or changes in website behavior. Additionally, there are various tools and software available that can help detect and report potential XSS vulnerabilities.**Q7: Who is most at risk of Cross-Site Scripting attacks?**A7: Any website or web application that allows user input without properly validating, sanitizing, or escaping it can be at risk of an XSS attack. This includes but is not limited to banks, online retailers, social media sites, and forums.

Related Finance Terms

  • Injection Attack
  • Script Vulnerability
  • Web Application Security
  • Malicious Script
  • Web Browser Exploitation

Sources for More Information

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