Analytics Stats Counter Statistics WordPress Plugin unauthenticated PHP Object injection vulnerability

Abstract

A PHP Object injection vulnerability was found in the Analytics Stats Counter Statistics WordPress Plugin, which can be used by an unauthenticated user to instantiate arbitrary PHP Objects. Using this vulnerability it is possible to execute arbitrary PHP code.

OVE ID

OVE-20160803-0005

Tested versions

This issue was successfully tested on the Analytics Stats Counter Statistics WordPress Plugin version 1.2.2.5.

Fix

There is currently no fix available.

Introduction

The Analytics Stats Counter Statistics WordPress Plugin analyses visitors statistics on a WordPress site. A PHP Object injection vulnerability was found in the Analytics Stats Counter Statistics WordPress Plugin, which can be used by an unauthenticated user to instantiate arbitrary PHP Objects.

Details

This issue is possible due to an unsafe call to unserialize() in the wpadm_unpack() method. The input is taken directly from the POST request as can be seen in the following code fragment:

wpadm.php:

if ( ! function_exists( 'wpadm_run' )) {
	function  wpadm_run($pl, $dir) {
		@set_time_limit(0);
		require_once dirname(__FILE__) . '/class-wpadm-method-class.php';
		$request_name = 'wpadm_'.$pl.'_request';
		if( isset( $_POST[$request_name] ) && ! empty ( $_POST[$request_name] ) ) {
			require_once dirname(__FILE__) . '/class-wpadm-core.php';
			$wpadm = new WPAdm_Core(**wpadm_unpack($_POST[$request_name])**, $pl, $dir);
			echo '<wpadm>'.wpadm_pack($wpadm->getResult()->toArray()).'</wpadm>';
			exit;
		}
	}
}
	
	
if ( ! function_exists( 'wpadm_unpack' )) {
	/**
	 * @param str $str
	 * @return mixed
	 */
	function wpadm_unpack( $str ) {
		return **unserialize( base64_decode( $str ) )**;
	}
}

It has been confirmed that this issues can be used to execute arbitrary PHP code.