hdweGUEST <= 2.1.1 Cross Site Scripting Vulnerabilities

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  Advisory: hdweGUEST <= 2.1.1 Cross Site Scripting Vulnerabilities

Release Date: 2006/07/18
Last Modified: 2006/07/18
Author: Tamriel [tamriel at gmx dot net]
Application: hdweGUEST 2.1.1
Risk: Low
Vendor Status: contacted | no reply | no patch available
Vendor Site: www.huttenlocher-webdesign.de

Overview:

Quote from www.huttenlocher-webdesign.de

"hwdeGUEST ist ein Gaestebuch geschrieben in PHP. Es bietet dem
Betreiber eine Vielzahl von Moeglichkeiten"

Details:

  In the new_entry.php are some possible cross site scripting
  vulnerabilities.

  This can be used to insert malicious code that will be executed
  on the client's machine.

  All user inputs are not checked by the script, only in this lines
  (arround line 250-255)

  ...

  $username=trim($username);
  $usernachricht=trim($usernachricht);
  if($GLOBALS[html_allowed]==0)
    {$usernachricht=strip_tags($usernachricht);}

  ...

  and the mail input is checked by this function:
  (arround line 70-80)

  ...

  if(strstr($adresse,"@"))
     {
        $temp_adresse=explode("@",$adresse);
        if(strstr($temp_adresse[1],"."))
           {
              if(strlen($adresse)<8)
                 {return false;}
                 else
                    {return true;}
           }
            else
               {return false;}
     }

  ...

Proof of Concept:

  Insert HTML/JS Code like "<u>name</u>" into the name input field 
  on "new entry" page.

Solution/Note:

  It is strongly recommended to update your script by yourself.
  Use the htmlentities() function and replace some insecure functions
  like the checke_email()'s one with proper code.

Greets:

  Greets fly out to all people at bluegeek.de

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