完美扫描PHP特殊一句话后门脚本

作者 Spider
网上公布的各种PHP后门全军覆没
针对一些特殊变形的后门需要自己添加特征
误报率不到百分之一

代码如下保存为*.php

error_reporting(E_ERROR);
ini_set('max_execution_time',20000);
ini_set('memory_limit','512M');
header("content-Type: text/html; charset=gb2312");

$matches = array(
'/function\_exists\s*\(\s*[\'|\"](popen|exec|proc\_open|system|passthru)+[\'|\"]\s*\)/i',
'/(exec|shell\_exec|system|passthru)+\s*\(\s*\$\_(\w+)\[(.*)\]\s*\)/i',
'/((udp|tcp)\:\/\/(.*)\;)+/i',
'/preg\_replace\s*\((.*)\/e(.*)\,\s*\$\_(.*)\,(.*)\)/i',
'/preg\_replace\s*\((.*)\(base64\_decode\(\$/i',
'/(eval|assert|include|require|include\_once|require\_once)+\s*\(\s*(base64\_decode|str\_rot13|gz(\w+)|file\_(\w+)\_contents|(.*)php\:\/\/input)+/i',
'/(eval|assert|include|require|include\_once|require\_once|array\_map|array\_walk)+\s*\(\s*\$\_(GET|POST|REQUEST|COOKIE|SERVER|SESSION)+\[(.*)\]\s*\)/i',
'/eval\s*\(\s*\(\s*\$\$(\w+)/i',
'/(include|require|include\_once|require\_once)+\s*\(\s*[\'|\"](\w+)\.(jpg|gif|ico|bmp|png|txt|zip|rar|htm|css|js)+[\'|\"]\s*\)/i',
'/\$\_(\w+)(.*)(eval|assert|include|require|include\_once|require\_once)+\s*\(\s*\$(\w+)\s*\)/i',
'/\(\s*\$\_FILES\[(.*)\]\[(.*)\]\s*\,\s*\$\_(GET|POST|REQUEST|FILES)+\[(.*)\]\[(.*)\]\s*\)/i',
'/(fopen|fwrite|fputs|file\_put\_contents)+\s*\((.*)\$\_(GET|POST|REQUEST|COOKIE|SERVER)+\[(.*)\](.*)\)/i',
'/echo\s*curl\_exec\s*\(\s*\$(\w+)\s*\)/i',
'/new com\s*\(\s*[\'|\"]shell(.*)[\'|\"]\s*\)/i',
'/\$(.*)\s*\((.*)\/e(.*)\,\s*\$\_(.*)\,(.*)\)/i',
'/\$\_\=(.*)\$\_/i',
'/\$\_(GET|POST|REQUEST|COOKIE|SERVER)+\[(.*)\]\(\s*\$(.*)\)/i',
'/\$(\w+)\s*\(\s*\$\_(GET|POST|REQUEST|COOKIE|SERVER)+\[(.*)\]\s*\)/i',
'/\$(\w+)\s*\(\s*\$\{(.*)\}/i',
'/\$(\w+)\s*\(\s*chr\(\d+\)/i'
);

function antivirus($dir,$exs,$matches) {
if(($handle = @opendir($dir)) == NULL) return false;
while(false !== ($name = readdir($handle))) {
if($name == '.' || $name == '..') continue;
$path = $dir.$name;
if(is_dir($path)) {
//chmod($path,0777);/*主要针对一些0111的目录*/
if(is_readable($path)) antivirus($path.'/',$exs,$matches);
} elseif(strpos($name,';') > -1 || strpos($name,'%00') > -1 || strpos($name,'/') > -1) {
echo '特征  '.$path.'
'; flush(); ob_flush();
} else {
if(!preg_match($exs,$name)) continue;
if(filesize($path) > 10000000) continue;
$fp = fopen($path,'r');
$code = fread($fp,filesize($path));
fclose($fp);
if(empty($code)) continue;
foreach($matches as $matche) {
$array = array();
preg_match($matche,$code,$array);
if(!$array) continue;
if(strpos($array[0],"\x24\x74\x68\x69\x73\x2d\x3e")) continue;
$len = strlen($array[0]);
if($len > 6 && $len < 200) {
echo '特征  '.$path.'
';
flush(); ob_flush(); break;
}
}
unset($code,$array);
}
}
closedir($handle);
return true;
}

function strdir($str) { return str_replace(array('\\','//','//'),array('/','/','/'),chop($str)); }

echo '
';
echo '路径: 
';
echo '后缀: 
';
echo '操作: 
';
echo '
';

if(file_exists($_POST['dir']) && $_POST['exs']) {
$dir = strdir($_POST['dir'].'/');
$exs = '/('.str_replace('.','\\.',$_POST['exs']).')/i';
echo antivirus($dir,$exs,$matches) ? '
扫描完毕' : '
扫描中断';
}