WordPress Store Locator Plus 4.5.09 Cross Site Scripting

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Cross-Site Scripting in Store Locator Plus for WordPress  
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Yorick Koster, July 2016  
  
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Abstract  
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A Cross-Site Scripting vulnerability was found in Store Locator Plus for  
WordPress. This issue allows an attacker to perform a wide variety of  
actions, such as stealing Administrators' session tokens, or performing  
arbitrary actions on their behalf. In order to exploit this issue, 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-20160724-0025  
  
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Tested versions  
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This issue was successfully tested on Store Locator Plus for WordPress  
version 4.5.09.  
  
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Fix  
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This issue has been addressed in Store Locator Plus for WordPress  
version 4.5.12.  
  
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Details  
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https://sumofpwn.nl/advisory/2016/cross_site_scripting_in_store_locator_plus_for_wordpress.html  
  
This issue exists in the file include/class.admin.locations.add.php and is caused due to the lack of output encoding on the start request parameter.  
  
$this->section_params['opening_html'] =  
"<form id='manualAddForm' name='manualAddForm' method='post'>" .  
( $this->adding ? '<input type="hidden" id="act" name="act" value="add" />' : '<input type="hidden" id="act" name="act" value="edit" />' ) .  
"<input type='hidden' name='id' " .  
"id='id' value='{$this->slplus->currentLocation->id}' />" .  
"<input type='hidden' name='locationID' " .  
"id='locationID' value='{$this->slplus->currentLocation->id}' />" .  
"<input type='hidden' name='linked_postid-{$this->slplus->currentLocation->id}' " .  
"id='linked_postid-{$this->slplus->currentLocation->id}' value='" .  
$this->slplus->currentLocation->linked_postid .  
"' />" .  
( isset( $_REQUEST['start'] ) ? "<input type='hidden' name='start' id='start' value='{$_REQUEST['start']}' />" : '' ) .  
"<a name='a{$this->slplus->currentLocation->id}'></a>";  
  
  
  
In order to exploit this issue, the attacker has to lure/force a logged on WordPress Administrator into opening a malicious website.  
  
Proof of concept  
  
http://<target>/wp-admin/admin.php?page=slp_manage_locations&start=%27%3E%3Cscript%3Ealert%281%29%3C%2Fscript%3E  
  
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Summer of Pwnage (https://sumofpwn.nl) is a Dutch community project. Its  
goal is to contribute to the security of popular, widely used OSS  
projects in a fun and educational way.  
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