36 lines
1.9 KiB
Markdown
36 lines
1.9 KiB
Markdown
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## Stored XSS
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As the name infers, the XSS payload is stored on the web application (in a database, for example) and then gets run when other users visit the site or web page.
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- **Potential Impact:**
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The malicious JavaScript could redirect users to another site, steal the user's session cookie, or perform other website actions while acting as the visiting user.
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**How to test for Stored XSS:**
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You'll need to test every possible point of entry where it seems data is stored and then shown back in areas that other users have access to; a small example of these could be:
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- Comments on a blog
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- User profile information
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- Website Listings
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- Button (Bypass filter that dont allow code) `<button onclick=alert(‘xss’)>click</button>`
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Sometimes developers think limiting input values on the client-side is good enough protection, so changing values to something the web application wouldn't be expecting is a good source of discovering stored XSS, for example, an age field that is expecting an integer from a dropdown menu, but instead, you manually send the request rather than using the form allowing you to try malicious payloads.
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Once you've found some data which is being stored in the web application, you'll then need to confirm that you can successfully run your JavaScript payload; your payload will be dependent on where in the application your code is reflected
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- **Example Scenario:**
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A blog website that allows users to post comments. Unfortunately, these comments aren't checked for whether they contain JavaScript or filter out any malicious code. If we now post a comment containing JavaScript, this will be stored in the database, and every other user now visiting the article will have the JavaScript run in their browser.
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