Description: XSS exploitation (Cross-Site Scripting) is the act of exploiting a vulnerability in a web application to execute malicious scripts in a user’s browser. This technique relies on injecting JavaScript, HTML, or Flash code into web pages viewed by other users. XSS exploitation can have various consequences, such as stealing session cookies, identity theft, redirecting to malicious sites, or executing unauthorized actions on behalf of the affected user. XSS vulnerabilities are generally classified into three types: reflected, stored, and DOM-based. Reflected XSS occurs when the malicious script is sent as part of a request and is reflected in the server’s response. Stored XSS, on the other hand, involves the script being stored on the server and delivered to users on future visits. Finally, DOM-based XSS occurs when the script executes in the client’s browser, manipulating the Document Object Model (DOM) of the page. XSS exploitation is one of the most common vulnerabilities in web applications and poses a significant risk to user security and the integrity of online data.
History: XSS exploitation was first identified in the late 1990s when developers began to notice that scripts could be injected into web applications. In 1999, the term ‘Cross-Site Scripting’ was coined by security researcher Jeremiah Grossman. Since then, the technique has evolved, and XSS vulnerabilities have been documented in various security databases, such as the OWASP Top Ten, which highlights the most critical threats to web application security.
Uses: XSS exploitation is primarily used in penetration testing to assess the security of web applications. Security professionals employ this technique to identify and demonstrate vulnerabilities in systems, allowing organizations to fix flaws before they are exploited by malicious attackers. Additionally, attackers may use XSS to commit fraud, steal sensitive information, or compromise user accounts.
Examples: An example of reflected XSS exploitation is when an attacker sends a malicious link to a user, which, when clicked, executes a script that steals their session cookies. In the case of stored XSS, an attacker could inject a script into a forum that, when viewed by other users, executes unauthorized actions on their accounts. An example of DOM-based XSS could be a script that modifies the content of a web page in the user’s browser, redirecting them to a phishing site.
