Description: A Cross-Site Scripting (XSS) attack is an exploitation technique that takes advantage of vulnerabilities in web applications to inject malicious scripts into the user’s browser. These scripts can be used to steal sensitive information, such as session cookies, user credentials, or personal data. The attack occurs when a web application does not properly validate user input, allowing an attacker to insert JavaScript, HTML, or other code that executes in the victim’s browser context. This can lead to manipulation of the user interface, redirection to malicious sites, or execution of unauthorized actions on behalf of the user. XSS attacks are classified into three main types: reflected, stored, and DOM-based, each with different execution methods and consequences. Preventing these attacks involves implementing security measures such as input validation and sanitization, using Content Security Policies (CSP), and properly encoding data before it is sent to the browser. The increasing reliance on web applications in everyday life has made protection against XSS a priority in web security.
History: The concept of XSS was first identified in the late 1990s when developers began to notice that web applications were vulnerable to script injection. In 2000, the term ‘Cross-Site Scripting’ was coined by security researcher Jeremiah Grossman. Over the years, the security community has documented numerous XSS incidents, leading to increased awareness of the need to protect web applications. In 2007, OWASP (Open Web Application Security Project) included XSS in its list of the top ten web security vulnerabilities, highlighting its relevance and the need for mitigation.
Uses: XSS attacks are primarily used to steal sensitive user information, such as login credentials, credit card data, and other personal information. They can also be used to carry out phishing attacks, where attackers trick users into revealing confidential information. Additionally, attackers may use XSS to propagate malware, redirect users to malicious sites, or manipulate the content of the web pages users visit.
Examples: A notable example of an XSS attack occurred in 2010 when an attacker exploited a vulnerability on Twitter’s website, allowing a script to be injected that redirected users to a phishing site. Another famous case was the MySpace attack in 2005, where a malicious script was used to modify user profiles and send unsolicited messages to other users. These incidents highlight the importance of implementing adequate security measures to prevent XSS attacks.
