Add check function

Author: jvazquez-r7

modules/exploits/unix/webapp/php_wordpress_total_cache.rb

@@ -217,4 +217,31 @@ def exploit
 			fail_with(Exploit::Failure::Unknown, "#{peer} - Unexpected redirection, maybe comments are moderated")
 		end
 	end
+
+	def check
+		res = send_request_cgi ({
+			'uri' => normalize_uri(target_uri.path),
+			'method' => 'POST'
+		})
+
+		if res.nil?
+			return Exploit::CheckCode::Unknown
+		end
+
+		if res.headers['X-Powered-By'] and res.headers['X-Powered-By'] =~ /W3 Total Cache\/([0-9\.]*)/
+			version = $1
+			if version <= "0.9.2.3"
+				return Exploit::CheckCode::Vulnerable
+			else
+				return Exploit::CheckCode::Safe
+			end
+		end
+
+		if res.body and res.body =~ /Performance optimized by W3 Total Cache/
+			return Exploit::CheckCode::Detected
+		end
+
+		return Exploit::CheckCode::Unknown
+
+	end
 end