Sometimes the methods for dealing with hostile or infected systems on the network are drastic, resulting in lost productivity, time, and energy. In one example the IT staff would physically shut down the user's main network port, sealing off all production systems, test systems, etc, until the hostile machine could be dealt with. Phone calls results, requiring the user to deal personally with the affected system. Now take Intel AMT's System Defense. Remotely quarantine a hostile system and use Altiris to remediate it. System Defense, it puts the power in the hands of the administrator remotely.



System Defense (formerly known as Circuit Breaker) allows network filtering at the level of AMT. Systems that have been compromised and are a threat to the network can be remotely quarantined, with certain ports and IP addresses available for remediation. For example the entire network can be filtered out except to the NS, and only those ports required for the Notification Server to remediate the client (install anti-virus, patches, remove harmful software, etc).


Note that testing is vital when using a mechanism that can potentially cut off a system from the network. The ease of remediating compromised systems remotely while quarantining from the main network will remain as long as the filters are properly configured. If not, the system may require a desk-side visit to bring back on the network.

System Defense

System Defense shows as Circuit Breaker in some versions of the Altiris Manageability Toolkit for Intel® vPro Technology. This feature allows a network filter to be placed at the hardware level via AMT. AMT will hijack the operating system's hold on the network connection and apply a secure filter based on a configuration file provided by the administrator.


See the following diagram for a representation of how System Defense (Network filtering) works:



This filter becomes a complete block that disallows any network communication in OR out, save those sources that are configured. Note that the parameters for allowing network communication are those of Sending IP Address and Port. This means that not only to systems have to be explicitly defined to be allowed through, but the ports they are using as well.



Use Cases

The following use cases will find real value with System Defense network filtering:


  • Virus attack from an infected vPro client - This cuts off the ability of that virus to send packets out on the network

  • Vulnerable vPro clients without anti-virus - Close off the ability of a virus from getting through to the vulnerable system

  • Vulnerable vPro clients without critical patches or updates - Quarantine systems, but allow NS to remediate to bring the system up to corporate security standards

  • Unauthorized Network use - plug a system that is found participating in unauthorized network use, whether it be unauthorized content, gross use of bandwidth for non-approved purposes, etc...

  • For fun - Drive a fellow administrator crazy by applying and removing filters randomly from his computer (Just kidding, don't try this at home, or at work for that matter)

Task Server Integration

As of Real Time Console Infrastructure release 6.3 the Task Server now has a Task type of Network Filter. This exclusively uses Intel AMT System Defense to apply a comprehensive filter that only allows strict communication to and from the NIC. Because of Task Server's sequencing engine and collection targeting, jobs using this can be setup to do a large number of things, including patching, critical application install such as anti-virus, and other critical computer maintenance items required by the organization.


Task Server Jobs

As a primer for details in this article, see the following article series on Altiris Juice:


See the Introduction for more information on jobs. There are two major types of a Network Filtering job:

  1. Apply a System Defense network filter, either the default filter allowing communication to the NS for remediation or a custom filter allowing access to necessary resources

  2. Remove a System Defense network filter to open back up general network communication


See the following screenshot for the option when this Task type is created:


  • The first radial button allows the application of a filter, either a custom or the default, with the added option of enabling anti-spoofing filter

  • The second radial button simply applies a PING filter to the target systems

  • The third and final radial button removes any filters previous applied to the system

Job Targeting

Because of the significance of System Defense and what it does to client computers, I'm going to cover how Task Server Jobs target systems. With a Task Server job you can add individual systems or whole collections of computers. Collections are either manually or dynamically defined and can have few or many systems therein. Multiple systems and collections can be attached to the running of a job, either on demand or by a schedule.


Since System Defense is essentially quarantining vPro Systems, any Task or Job should be tested in a lab environment to ensure workability. If a custom filter is used, the potential to decapitate vPro systems from the network becomes a very real, very severe consequence of improper filters. Take the scenario of having a custom filter that does not allow proper communication back to the Notification Server or another critical resource (like Task Server) in the remediation process. Once the trigger is pulled and the System Defense network filter has been applied, those systems now have insufficient network access to remediate, which may mean that a remote Task to remove the filter is unavailable. IF the job contained half the computers in the environment, the impact is huge.


I say again: Test every filter within every job to ensure everything works properly!


Filter Configuration

Real-Time System Manager allows you to create your own filter configuration files to use with a System Defense Task. In some instances it may be required to open additional ports or destination IPs for full remediation to occur. If you use Package Servers to deliver software you may need to allow communication to these systems.


Edit Network Filters Utility

A utility is provided to create, edit, or otherwise revise any filter file to be used by a System Defense Task. This filter is provided via the Altiris Knowledgebase.


Installation The ENF Utility

See the following article for both the guide in using the utility and to download the utility directly:


The attached file is a zip. The file included Altiris_ENF_6_2.exe will install the utility on the computer it is executed on. The prerequisites for this utility include:


  1. Windows 2000 Server or Windows 2003 Server

  2. .NET 1.1

  3. Notification Server 6.0 Sp3

  4. At least Real-Time Console Infrastructure 6.2

Using the ENF Utility

Once the installation has run, the Altiris Console can now be used to edit the filters. It's found in the Altiris Console under View > Solutions > Real Time Console Infrastructure > Configuration > and click on ‘Edit Network Filters'. The console provided a spreadsheet of the current filters for the default filter file, as shown:



When you click the Edit pencil icon, a subsequent window will appear. This wizard will walk through editing of the filters. This same wizard is used to add new filters to the list. This wizard is robust and allows minute tuning of what ports are allowed, both for sending and receiving from the NS and from the host AMT computer. The wizard appears as follows:




The default file is called CBFilters.xml and is found at \Program Files\Altiris\RTSM\UIData\. Other files can be created and used in the System Defense Filtering Tasks. It is configurable per Task or Job instance.



NOTE: If you plan on making changes to the default filter file, it is recommended to browsing to the file and making a copy of it. The copy will be a backup to use in case the default file becomes corrupt through editing or for related recovery options.



The best way to know how to open which ports to enable the access you require is to consult the documentation for the application or mechanism you are trying to work with. For example the Task Server uses ports 50120 through 50124, and these ports need to be opened between the Task Server to be used and the client computer.




As previously indicated, make sure you test every system defense task and job you plan to use out in your environment. It's one thing to test against one or two systems where you can manually resolve any unforeseen problems, but if a targeted collection contains many systems and the job or task as an unforeseen issue, this can cut off all these systems from the necessary access to restore network functionality. So test, test, test, and test again before deploying large jobs using System Defense network filtering.


When used properly, this tool enables administrators to remotely deal with vulnerable or infected systems remotely, and stop unauthorized network use. With System Defense enable your administrators to more quickly deal with threats, and remediate in much less time.