Multiple Firewall Products Bypass Vulnerability

From: Ferruh Mavituna (ferruh_at_mavituna.com)
Date: 01/03/05

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    To: <bugtraq@securityfocus.com>
Date: Mon, 3 Jan 2005 22:09:38 +0200

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    Multiple Firewall Products Bypass Vulnerability
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    Online URL : http://ferruh.mavituna.com/article/?769
    Download POC : http://ferruh.mavituna.com/opensource/firewallbypass.zip
    (Also I attached vbs files as txt, one of them is -mousecontrol.txt- vb.net
    source code)

    This is a generic problem of common Personal Firewall products which are
    accept shortcuts or provide an interface that enables to click without
    require a password for controlled actions (acting as server -listening
    ports-, executing another program, connecting to another computer etc.).

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    Problem;
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    Most of personal firewalls allow shortcuts or interface for controlling
    traffic. It's simple to bypass these firewalls by a multithreaded program
    and sending keys or by contolling mouse.

    This flaw enables that any Trojan or similar programs can easily bypass
    firewall and act as a server or access to another computer. Also most of
    these firewalls have a "remember" option so if you bypass firewall and
    successfully exploit it, firewall will never ask again.

    This is a similar threat with shattering attacks, but different method and
    impact.

    Vulnerable Products (Sending Key Method and Mouse Control);
    These products are vulnerable to both of "Sending Key Method" and "Mouse
    Control Method"

    Test Platforms;
    Fully Patched Windows XP Professional and Windows 2003 Enterprise Edition
    (May 19, 2004 - 01.01.2005)

    1. ZoneAlarm / ZoneAlarm Pro (www.zonelabs.com) | Fixed
            I. 4.5.530.000 - Tested
            II. 4.5.538.001 - Tested
            III. 5 and newer versions are not vulnerable...

    2. Kerio (www.kerio.com)
            I. 4.0.14 - Tested
            II. All Versions

    3. Agnitium Outpost Firewall (www.agnitium.com)
            I. 2.1.303.4009 (314) - Tested
            II. 2.5.369.4608 (369) - Tested
            II. All Versions

    4. Kaspersky Anti-Hacker (www.kaspersky.com)
            I. 1.5.119.0 - Tested
            II. All Versions

    5. Look 'n' Stop (www.looknstop.com)
            I. 2.04p2 - Tested
            II. All Versions

    6. Symantec's Norton Personal Firewall (www.norton.com)
            I. 2004 - Tested
            II. All Versions

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    Vulnerable Products (Mouse Control);
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    These products are only vulnerable to "Mouse Control Method", because they
    don't accept shortcuts but still vulnerable to "Mouse Control" attacks.

    1. Panda Platinum Internet Security
            I. 8.03 (tested)
            II. All Versions

    2. Omniquad Personal Firewall
            I. 1.1 (tested)
            II. All Versions

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    Proof of Concept;
    -------------------------------------------------------------------
    2 Proof of Concepts attached to advisory (also some other POCs for some
    firewalls)

    First POC (bypassSendKey.vbs) written in VBScript (.vbs), This POC include
    required samples for ZoneAlarm, Kerio, Agnitium, Kaspersky Anti-Hacker, Look
    'n' Stop and Symantec's Norton Personal Firewall. This script is executing
    an instance of itself for multithreading and send shortcuts to firewall
    while first instance trying to connect internet. I didn't write an auto
    determine firewall function (but it's so easy), so you need to set it by
    yourself.

    Second (bypassMouseControl.txt) simulates an example of bypassing Zone Alarm
    Firewall by with mouse control, code in VB.NET. Program is not using a real
    multithread because some firewalls interrupt executing of program directly.
    So program is executing another instance of itself with an argument.

    Both of them add themselves to secure app list of firewalls and then bypass
    active firewall.

    Also I attached testFirewall.vbs for testing your firewall for application
    control.

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    Solution;
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    All firewalls should ask password for all kind of "Allow" actions. In fact
    passwords can be fooled because of its nature but it is the best user
    friendly / secure solution for protection.

    As a user of these firewalls, if your firewall supports to "deny all
    default" option, enable it, so your firewall deny all connections by
    default. After that you may can manually select programs for allow them.

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    Final Words;
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    This is a methodology for bypassing interacted firewalls so it's possible
    that this advisory affects other firewalls in market. Also it's possible
    that future firewalls will be affected too. I think for now this is a
    serious problem for firewalls, until they imply password/random human need
    text method for "Allow/Deny" actions.

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    History;
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    Discovered: 03.05.2004
    Vendors Informed: 28.08.2004
    Published: 03.01.2005

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    Vendors Status;
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    Special thanks to ZoneLabs Team.

    Ferruh Mavituna
    http://ferruh.mavituna.com
    pgpkey : http://ferruh.mavituna.com/PGPKey.asc

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