Darren Reed wrote:
> David Chieu wrote:
>
>> Darren Reed wrote:
>> ...
>>
>>> How does it defend against being brute forced?
>>
>> I don't understand the question. Can you give an example of brute 
>> forced?
>
>
> I use a dictionary as a source of usernames and passwords
> and send correctly formatted data at the NIC (using a combination
> of usernames and passwords) until it respods with a message
> indicating a successful authentication attempt.
>
> Darren
>
I see. A stronger password (w/ symbols e.g. !,@, etc.) reduces 
vulnerability of a dictionary attack. I image that an AMD engineer could 
explore the like :-) If stronger security model is needed, AMT supports 
certificate-based authentication as well. I'm not an expert in this 
field, so I quote the following excerpt from the Intel website.

http://softwarecommunity.intel.com/articles/eng/1004.htm
...
"Authentication and Authorization

Network communications with an Intel AMT-enabled platform should be 
performed in the most secure way available. An IT administrator can 
configure for certificate-based authentication and optionally select 
mutual authentication. Intel AMT has an Access Control List used to 
authorize all access requests. Intel AMT can use the Kerberos option of 
Microsoft Active Directory to simplify the authorization process. A 
remote setup and configuration server is required to prepare Intel AMT 
for secure operations.

Configuring the Intel AMT Security Model

Both the Intel AMT platform and the Setup and Configuration (S&C) Server 
start with two pieces of shared information ? a platform ID and a 
pre-shared key (PSK). The first communication between Intel AMT and the 
setup and configuration server is an unencrypted ?hello? message from 
Intel AMT to the server that contains the platform identifier. The S&C 
Server then performs the setup and configuration process using the PSK 
and the TLS-PSK protocol for authentication and encryption of the 
configuration traffic. The S&C Server downloads Certificates to the 
Intel AMT platform, which stores them in non-volatile memory. The 
certificates trace to an enterprise certificate authority and are used 
by Intel AMT to authenticate to Management Console applications. If 
Intel AMT is configured for mutual authentication, the S&C Server must 
provide a client certificate for each application that will communicate 
with Intel AMT.

The S&C server also establishes an Access Control List, enables certain 
Intel AMT features, and configures device settings. At the end of the 
setup and configuration process, the keys generated and used during the 
process are deleted. All subsequent communications use the certificates 
and Transport Layer Security (TLS) for authentication, confidentiality 
(encryption), and integrity (mutual authentication). Intel AMT performs 
authorization using the Access Control List, as described in the 
following section. HTTP Digest authentication is used for the SOAP over 
HTTP communications. The Redirection feature uses secure sockets layer 
(SSL) to establish a secure connection between the remote console and 
the Intel AMT platform. See the User?s Guide to the Sample Setup and 
Configuration Application for additional information.

Access Control Lists and Realms

The Intel AMT Access Control List (ACL) manages who has access to which 
capabilities within the device. An ACL entry has a user ID and a list of 
realms to which a user has access. This access is required to use the 
functionality associated with a realm. In the table above, each 
interface or service is listed with its realm. A user can be granted 
access to one or more realms.

The single default user is named ?admin? and has ?PTAdministrationRealm? 
privileges, which includes privileges for all Intel AMT realms. The 
admin user can use the commands in the Security Administration interface 
to create additional ACL entries for additional users. As part of the 
setup and configuration process, create the users necessary for an ISV 
application, subject to the limits on the number of available ACL entries.

There are two kinds of ACL entries: Kerberos and non-Kerberos. The main 
difference between them is that Kerberos entries have an Active 
Directory SID to identify a user or group of users. Non-Kerberos entries 
have a username and password for user identification. See Intel AMT 
Integration with Active Directory for a description of the difference 
between these entries."



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