What is cross-site scripting?
Cross-site scripting (also known as XSS) is a web security vulnerability that allows an attacker to compromise the interactions that users have with a vulnerable application. It allows an attacker to circumvent the same origin policy, which is designed to segregate different websites from each other.
What is a postMessage vulnerability?
HTML5 postMessage introduces a new taint source in the form of the message payload (Event. data). A DOM-based Cross-Site Scripting (XSS) vulnerability occurs when the payload of a message event is handled in an unsafe way.
What are the two primary classification of XSS?
There is no single, standardized classification of the types of cross-site scripting attacks, but most experts distinguish between at least two primary types: non-persistent and persistent. Other sources further divide these two groups into traditional (caused by server-side code) and DOM-based (in client-side code).
How is XSS performed?
XSS attacks occur when an attacker uses a web application to send malicious code, generally in the form of a browser side script, to a different end user. An attacker can use XSS to send a malicious script to an unsuspecting user.
What causes cross-site scripting?
Cross-Site Scripting (XSS) attacks occur when: Data enters a Web application through an untrusted source, most frequently a web request. The data is included in dynamic content that is sent to a web user without being validated for malicious content.
Is window postMessage secure?
postMessage is generally considered very secure as long as the programmer is careful to check the origin and source of an arriving message. Acting on a message without verifying its source opens a vector for cross-site scripting attacks. See Zalewski [4].
What is cross site scripting and how can you fix it?
What is Cross-site Scripting and How Can You Fix it? Cross-site Scripting (XSS) is a client-side code injection attack. The attacker aims to execute malicious scripts in a web browser of the victim by including malicious code in a legitimate web page or web application.
Which is the most common cross site scripting attack?
Reflected cross-site scripting. This is the most commonly seen cross-site scripting attack. With a reflected attack, malicious code is added onto the end of the url of a website; often this will be a legitimate, trusted website. When the victim loads this link in their web browser, the browser will execute the code injected into the url.
How to use cross site scripting ( XSS ) in OWASP?
In addition, the OWASP WebGoat Project training application has lessons on Cross-Site Scripting and data encoding. XSS attacks may be conducted without using tags. Other tags will do exactly the same thing, for example: or other attributes like: onmouseover, onerror.
Which is an example of reflected cross site scripting?
Reflected cross-site scripting. Reflected XSS is the simplest variety of cross-site scripting. It arises when an application receives data in an HTTP request and includes that data within the immediate response in an unsafe way. Here is a simple example of a reflected XSS vulnerability:
