WordPress Google Analytics Counter Tracker 3.1.5 PHP Object Injection

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Google Analytics Counter Tracker WordPress Plugin unauthenticed PHP  
Object injection vulnerability  
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Remco Vermeulen, July 2016  
  
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Abstract  
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A PHP Object injection vulnerability was found in Google Analytics  
Counter Tracker, which can be used by an unautenthicated user to  
instantiated arbitrary PHP Objects. Using this vulnerability it is  
possible to execute arbitrary PHP code.  
  
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OVE ID  
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OVE-20160712-0035  
  
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Tested versions  
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This issue was succesfully tested on the Google Analytics Counter  
Tracker WordPress Plugin version 3.1.5.  
  
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Fix  
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This issue has been addressed in Google Analytics Counter Tracker  
version 3.5.1.  
  
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Details  
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https://sumofpwn.nl/advisory/2016/google_analytics_counter_tracker_wordpress_plugin_unauthenticed_php_object_injection_vulnerability.html  
  
This issue is possible due to an unsafe call to unserialize() in the proccessRequest() method. The input is taken directly from the wpadm_ga_request cookie as can be seen in the following code fragment:  
  
class.wpadm-ga.php:  
  
protected static function proccessRequest() {  
$request_name = self::REQUEST_PARAM_NAME;  
$params = unserialize(base64_decode($_POST[$request_name]));  
  
$v = self::verifySignature($params['sign'], get_option('wpadm_ga_pub_key'), md5(serialize($params['data'])));  
  
It has been confirmed that this issues can be used to execute arbitrary PHP code.  
  
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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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