Home > Article > Backend Development > Detailed explanation of how webshell scans files for Trojans in PHP
这篇文章主要介绍了PHP实现webshell扫描文件木马的方法,涉及php针对数值传输的过滤操作与文件识别等相关安全操作技巧,需要的朋友可以参考下
具体如下:
可扫描 weevelyshell 生成 或加密的shell 及各种变异webshell
目前仅支持php
支持扫描 weevelyshell 生成 或加密的shell
支持扫描callback一句话shell
支持各种php大马
代码如下:
<!DOCTYPE html> <html> <head> <meta charset='gb2312'> <title>PHP web shell scan</title> </head> <body> </body> <?php define("SELF",php_self()); error_reporting(E_ERROR); ini_set('max_execution_time',20000); ini_set('memory_limit','512M'); header("content-Type: text/html; charset=gb2312"); function weevelyshell($file){ $content=file_get_contents($file); if( ( preg_match('#(\$\w{2,4}\s?=\s?str_replace\("\w+","","[\w_]+"\);\s?)+#s',$content)&& preg_match('#(\$\w{2,4}\s?=\s?"[\w\d\+\/\=]+";\s?)+#',$content)&& preg_match('#\$[\w]{2,4}\s?=\s\$[\w]{2,4}\(\'\',\s?\$\w{2,4}\(\$\w{2,4}\("\w{1,4}",\s?"",\s?\$\w{2,4}\.\$\w{2,4}\.\$\w{2,4}\.\$\w{2,4}\)\)\);\s+?\$\w{2,4}\(\)\;#',$content)) || (preg_match('#\$\w+\d\s?=\s?str_replace\(\"[\w\d]+\",\"\",\"[\w\d]+\"\);#s',$content)&& preg_match('#\$\w+\s?=\s?\$[\w\d]+\(\'\',\s?\$[\w\d]+\(\$\w+\(\$\w+\(\"[[:punct:]]+\",\s?\"\",\s?\$\w+\.\$\w+\.\$\w+\.\$\w+\)\)\)\);\s?\$\w+\(\);#s',$content)) ){ return true; } } function callbackshell($file){ $content=file_get_contents($file); if( preg_match('#\$\w+\s?=\s?\$_(?:GET|POST|REQUEST|COOKIE|SERVER)\[.*?\]#is',$content)&& preg_match('#\$\w+\s?=\s?(?:new)?\s?array\w*\s?\(.*?_(?:GET|POST|REQUEST|COOKIE|SERVER)\[.*?\].*?\)+#is',$content)&& preg_match('#(?:array_(?:reduce|map|udiff|walk|walk_recursive|filter)|u[ak]sort)\s?\(.*?\)+?#is',$content) ) return true; } function php_self(){ $php_self=substr($_SERVER['PHP_SELF'],strrpos($_SERVER['PHP_SELF'],'/')+1); return $php_self; } $matches = array( '/mb_ereg_replace\([\'\*\s\,\.\"]+\$_(?:GET|POST|REQUEST|COOKIE|SERVER)\[[\'\"].*?[\'\"][\]][\,\s\'\"]+e[\'\"]'/is, '/preg_filter\([\'\"\|\.\*e]+.*\$_(?:GET|POST|REQUEST|COOKIE|SERVER)/is', '/create_function\s?\(.*assert\(/is', '/ini_get\(\'safe_mode\'\)/i', '/get_current_user\(.*?\)/i', '/@?assert\s?\(\$.*?\)/i', '/proc_open\s?\(.*?pipe\',\s?\'w\'\)/is', '/sTr_RepLaCe\s?\([\'\"].*?[\'\"],[\'\"].*?[\'\"]\s?,\s?\'a[[:alnum:][:punct:]]+?s[[:alnum:][:punct:]]+?s[[:alnum:][:punct:]]+?e[[:alnum:][:punct:]]+?r[[:alnum:][:punct:]]+?t[[:alnum:][:punct:]]+?\)/i', '/preg_replace_callback\(.*?create_function\(/is', '/filter_var(?:_array)?\s?.*?\$_(?:GET|POST|REQUEST|COOKIE|SERVER)\[[\'\"][[:punct:][:alnum:]]+[\'\"]\][[:punct:][:alnum:][:space:]]+?assert[\'\"]\)/is', '/ob_start\([\'\"]+assert[\'\"]+\)/is', '/new\s?ReflectionFunction\(.*?->invoke\(/is', '/PDO::FETCH_FUNC/', '/\$\w+.*\s?(?:=|->)\s?.*?[\'\"]assert[\'\"]\)?/i', '/\$\w+->(?:sqlite)?createFunction\(.*?\)/i', '/eval\([\"\']?\\\?\$\w+\s?=\s?.*?\)/i', '/eval\(.*?gzinflate\(base64_decode\(/i', '/copy\(\$HTTP_POST_FILES\[\'\w+\'\]\s?\[\'tmp_name\'\]/i', '/register_(?:shutdown|tick)_function\s?\(\$\w+,\s\$_(?:GET|POST|REQUEST|COOKIE|SERVER)\[.*?\]\)/is', '/register_(?:shutdown|tick)_function\s?\(?[\'\"]assert[\"\'].*?\)/i', '/call_user_func.*?\([\"|\']assert[\"|\'],.*\$_(?:GET|POST|REQUEST|COOKIE|SERVER)\[[\'|\"].*\]\)+/is', '/preg_replace\(.*?e.*?\'\s?,\s?.*?\w+\(.*?\)/i', '/function_exists\s*\(\s*[\'|\"](popen|exec|proc_open|system|passthru)+[\'|\"]\s*\)/i', '/(exec|shell_exec|system|passthru)+\s*\(\s*\$_(\w+)\[(.*)\]\s*\)/i', '/(exec|shell_exec|system|passthru)+\s*\(\$\w+\)/i', '/(exec|shell_exec|system|passthru)\s?\(\w+\(\"http_.*\"\)\)/i', '/(?:john\.barker446@gmail\.com|xb5@hotmail\.com|shopen@aventgrup\.net|milw0rm\.com|www\.aventgrup\.net|mgeisler@mgeisler\.net)/i', '/Php\s*?Shell/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*\(.*?\$_(?:GET|POST|REQUEST|COOKIE|SERVER|SESSION)+\[(.*)\]\s*\)/i', '/eval\s*\(\s*\(\s*\$\$(\w+)/i', '/((?:include|require|include_once|require_once)+\s*\(?\s*[\'|\"]\w+\.(?!php).*[\'|\"])/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(strstr($name,SELF)) continue; //$path=iconv("UTF-8","gb2312",$path); if(is_dir($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 <input type="text" style="width:250px;" value="解析漏洞"> '.$path.'<p></p>'; flush(); ob_flush(); } else { if(!preg_match($exs,$name)) continue; if(filesize($path) > 10000000) continue; $fp = fopen($path,'r'); $code = fread($fp,filesize($path)); fclose($fp); if(empty($code)) continue; if(weevelyshell($path)){ echo '特征 <input type="text" style="width:250px;" value="weevely 加密shell"> '.$path.'<p></p>'; flush(); ob_flush(); }elseif(callbackshell($path)){ echo '特征 <input type="text" style="width:250px;" value="Callback shell"> '.$path.'<p></p>'; flush(); ob_flush(); } foreach($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 && $len < 200) { echo '特征 <input type="text" style="width:250px;" value="'.htmlspecialchars($array[0]).'"> '.$path.'<p></p>'; flush(); ob_flush(); break; } } unset($code,$array); } } closedir($handle); return true; } function strdir($str) { return str_replace(array('\\','//','//'),array('/','/','/'),chop($str)); } echo '<form method="POST">'; echo '路径: <input type="text" name="dir" value="'.($_POST['dir'] ? strdir($_POST['dir'].'/') : strdir($_SERVER['DOCUMENT_ROOT'].'/')).'" style="width:398px;"><p></p>'; echo '后缀: <input type="text" name="exs" value="'.($_POST['exs'] ? $_POST['exs'] : '.php|.inc|.phtml').'" style="width:398px;"><p></p>'; echo '操作: <input type="submit" style="width:80px;" value="scan"><p></p>'; echo '</form>'; if(file_exists($_POST['dir']) && $_POST['exs']) { $dir = strdir($_POST['dir'].'/'); $exs = '/('.str_replace('.','\\.',$_POST['exs']).')/i'; echo antivirus($dir,$exs,$matches) ? '</br ><p></p>扫描完毕!' : '</br > <p></p>扫描中断'; } ?> </html>
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