Background[ edit ] Security on the web depends on a variety of mechanisms, including an underlying concept of trust known as the same-origin policy. Content from URLs where any of these three attributes are different will have to be granted permissions separately. Exploiting one of these, attackers fold malicious content into the content being delivered from the compromised site. When the resulting combined content arrives at the client-side web browser, it has all been delivered from the trusted source, and thus operates under the permissions granted to that system. By finding ways of injecting malicious scripts into web pages, an attacker can gain elevated access-privileges to sensitive page content, to session cookies, and to a variety of other information maintained by the browser on behalf of the user. Cross-site scripting attacks are a case of code injection.

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They are well know vulnerabilities, with well-known solutions. They are caused by insufficient user input sanitization, and result in malicious code being executed in the browser of the user visiting the site. I believe one of the reason these flaws are still present in new websites is due to the fact that their exploitation and consequences are not fully understood.

Here are few misconceptions I have heard. This is just for demonstration purposes. A successful XSS injection can insert any JavaScript into the page, which can, amongst other things: steal user credentials login, password, session, etc. SQL injection is all about reading data SQL Injection is not only used to dump a database, or to login without valid user credentials. A lot of web applications, like Wordpress, store the site content into a database.

If an attacker get write access to the database, he can insert malicious code which will then be rendered for all users. Since the "bad" content is often shown in the URL the user clicks on, users should simply be more careful.

First, "bad" links can be hidden with a URL shortener, for example and users may not be aware were they will be redirected. Second, all attacks are not necessarily transient. It is the responsibility of the webmaster to protect users. This responsibility should not be placed on each user.

A good blacklist will do the trick User input filtering is often performed by a blacklist: allow anything, except a few dangerous strings.

These 2 lines will make Internet Explorer load and execute JavaScript for evil. It can hide in a link, tag attributes, CSS, etc.

I hope that the high-profile attacks that happened recently will push web developers to pay more attention to the code injection vulnerabilities. Many programming frameworks include libraries and functions to take care of most of these issues.

Hopefully they will be used everywhere user input is received and displayed.


Cross-site scripting (XSS)

All rights reserved. The Exploit Database is a non-profit project that is provided as a public service by Offensive Security. The Exploit Database is a CVE compliant archive of public exploits and corresponding vulnerable software, developed for use by penetration testers and vulnerability researchers. Our aim is to serve the most comprehensive collection of exploits gathered through direct submissions, mailing lists, as well as other public sources, and present them in a freely-available and easy-to-navigate database. The Exploit Database is a repository for exploits and proof-of-concepts rather than advisories, making it a valuable resource for those who need actionable data right away. The Google Hacking Database GHDB is a categorized index of Internet search engine queries designed to uncover interesting, and usually sensitive, information made publicly available on the Internet. In most cases, this information was never meant to be made public but due to any number of factors this information was linked in a web document that was crawled by a search engine that subsequently followed that link and indexed the sensitive information.


Cross-site scripting





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