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Subject: RE: {Fraud?} {Disarmed} RE: [ActiveDir] RODC and computer accounts that are allowed to have their creds replicated.
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florianUser is Offline

Posts:87

01/09/2009 9:02 AM  
Mike,



I guess the „client“ part is the reason why LM and NTLM are still accepted.
Although NT4 BDCs have been gone in a 2008-domain, NT4 clients may not. We
have customers on Server 2003 looking at Server 2008 now running legacy CAD
apps or applications controlling plants that are on NT4 that can’t be
updated. “Legacy support” is, I guess, still the reason the setting has this
standard config.



No one stops you from changing it away from the default in your corp net and
your implementation, though.



Cheers,



Florian



From: ActiveDir-owner@mail.activedir.org
[mailto:ActiveDir-owner@mail.activedir.org] On Behalf Of Thommes, Michael M.
Sent: Freitag, 9. Januar 2009 14:03
To: ActiveDir@mail.activedir.org
Subject: RE: {Fraud?} {Disarmed} RE: [ActiveDir] RODC and computer accounts
that are allowed to have their creds replicated.



Hi Susan,

Would you have any idea why the W2K8 default is only level 3 “Send
NTLMv2 authentication only” and not Level 5 “DC refuses LM and NTLM
authentication (accepts only NTLMv2)? It seems to me anyone running a W2K8
domain has long ago gotten rid of any pre-NT4/SP4 clients. Any thoughts are
appreciated. Thanks.



Mike Thommes



_____

From: ActiveDir-owner@mail.activedir.org
[mailto:ActiveDir-owner@mail.activedir.org] On Behalf Of Susan Bradley
Sent: Friday, January 09, 2009 1:48 AM
To: ActiveDir@mail.activedir.org
Subject: Re: {Fraud?} {Disarmed} RE: [ActiveDir] RODC and computer accounts
that are allowed to have their creds replicated.



"NTLMv1 is vulnerable to sniff-an-crack attacks
NTLMv2 is not vulnerable"

http://support.microsoft.com/kb/823659

LAN Manager (LM) authentication is the protocol that is used to authenticate
Windows clients for network operations, including domain joins, accessing
network resources, and user or computer authentication. The LM
authentication level determines which challenge/response authentication
protocol is negotiated between the client and the server computers.
Specifically, the LM authentication level determines which authentication
protocols that the client will try to negotiate or that the server will
accept. The value that is set for LmCompatibilityLevel determines which
challenge/response authentication protocol is used for network logons. This
value affects the level of authentication protocol that clients use, the
level of session security negotiated, and the level of authentication
accepted by servers, according to the following table.

Get rid of those pesky older OSs would be a good start. :-)

It looks like 2k8 is default Network Security: Lan Manager authentication
level: Send NTLM v2 response only

Gabriele Scolaro wrote:

Brrrr I recall Marcus Murray session was one of those who really shocked me!



TechNet Webcast: Why I Can Hack Your Network in a Day! [A live demonstration
of techniques and tools used by hackers to compromise your network] (Level
300) (ID:1032340737)

http://www.microsoft.com/events/series/detail/webcastdetails.aspx?seriesid=9
6
<http://www.microsoft.com/events/series/detail/webcastdetails.aspx?seriesid=
96&webcastid=2783> &webcastid=2783

http://msevents.microsoft.com/cui/WebCastEventDetails.aspx?EventID=103234073
7
<http://msevents.microsoft.com/cui/WebCastEventDetails.aspx?EventID=10323407
37&EventCategory=3&culture=en-US&CountryCode=US>
&EventCategory=3&culture=en-US&CountryCode=US



Before that, I was _ingenuously_ recommending my DAs colleagues to use runas
to manage AD from their workstation…. :-(



is there any countermeasure to address or at least mitigate that security
issue?

what’s the recommended way to manage AD? (e.g. a dedicated hardened VM to
connect to via secure RDP)



Thanks – (yet afraid and worried) Gabriele.



From: ActiveDir-owner@mail.activedir.org
[mailto:ActiveDir-owner@mail.activedir.org] On Behalf Of Crawford, Scott
Sent: lunedì 5 gennaio 2009 22.02
To: ActiveDir@mail.activedir.org
Subject: RE: [ActiveDir] RODC and computer accounts that are allowed to have
their creds replicated.



I think Jorge’s point is that cracking is unnecessary.



Hash injection Attacks in a Windows Network

aka

Why an exposed LM/NTLM Hash is comparable to a clear-text password

aka

Why a 127 character long password is not necessarily stronger than a 4
character long password

aka

Why generating LM/NTLM rainbow tables is a complete waste of time

aka

Passing-the-hash for direct authentication to remote systems

aka

Why one vulnerable system can compromise the entire Active directory forest

aka

One of the scariest Windows authentication hacks you ever saw.......

http://truesecurity.se/blogs/murray/archive/2007/03/16/why-an-exposed-lm-ntl
m-hash-is-comparable-to-a-clear-text-password.aspx



From: ActiveDir-owner@mail.activedir.org
[mailto:ActiveDir-owner@mail.activedir.org] On Behalf Of Michael B. Smith
Sent: Monday, January 05, 2009 2:38 PM
To: ActiveDir@mail.activedir.org
Subject: RE: [ActiveDir] RODC and computer accounts that are allowed to have
their creds replicated.



It’s certainly possible to crack the hash with rainbow tables. My 64 GB
tables get more than 99% of passwords.



Regards,



Michael B. Smith, MCITP:SA,EMA/MCSE/Exchange MVP

My blog: http://TheEssentialExchange.com/blogs/michael

I'll be at TEC'2009! http://www.tec2009.com/vegas/index.php



From: ActiveDir-owner@mail.activedir.org
[mailto:ActiveDir-owner@mail.activedir.org] On Behalf Of Jorge de Almeida
Pinto
Sent: Monday, January 05, 2009 3:00 PM
To: ActiveDir@mail.activedir.org
Subject: RE: [ActiveDir] RODC and computer accounts that are allowed to have
their creds replicated.



Did you know it is possible to misuse an AD account when having: the logon
name and the password hash? (I do not care about the actual password)



Met vriendelijke groeten / Kind regards,



Ing. Jorge de Almeida Pinto

Senior Technical Consultant

MVP Identity & Access - Directory Services



Oxford Computer Group Benelux

(: +31 (0)6 26.26.62.80 | (: +31 (0)70 36.21.045 | 7: +31 (0)70 36.21.677
-: Sweelinckplein 9 - 11 (unit 11), 2517 GK, Den Haag, The Netherlands
(Google
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________________________________________________________________

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MVP Home Site à https://mvp.support.microsoft.com/

MVP Overview à https://mvp.support.microsoft.com/mvpexecsum

BLOG à http://blogs.dirteam.com/blogs/jorge/default.aspx

________________________________________________________________



From: ActiveDir-owner@mail.activedir.org
[mailto:ActiveDir-owner@mail.activedir.org] On Behalf Of Tony Gordon
Sent: Monday, January 05, 2009 20:45
To: ActiveDir@mail.activedir.org
Subject: RE: [ActiveDir] RODC and computer accounts that are allowed to have
their creds replicated.




Appreciate everyone's answers.

member: CN=Domain Controllers,CN=Users,DC=trouble,DC=loc

:). OK, so the Domain Controller's password will not be replicated to the
RODC. Should have looked before asking.

The specific risk is that the password of all computer accounts is still
distributed on all RODCs. I would still use the specific allow group for a
particular RODC and automate the group membership in some way using scripts
or your IdAM solution (e.g. ILM) if you already have such.

IdAM is only managing user accounts not computer accounts. So I guess the
question should have been formulated as:

How much of a risk at this time is if the passwords of the member computers
are replicated to the RODCs?

Computer passwords should be fairly strong and NTLM hash storage is disabled
by the policy (IIRC they are longer then 14 char and not stored anyway).

So how much of a risk it really is?



Thank you, Tony.


Tony Gordon
Windows 2003 & 2000 MCSE, Windows 2003 MCSA, PMP
ITS Infrastructure Engineering
Hewitt Associates | 100 Half Day Road | Lincolnshire, IL 60069 | USA
Tel 847.295.5000 x50526 | Fax 847.554.1574
tony dot gordon at hewitt dot com | www.hewitt.com


From:

joe <mailto:listmail@joeware.net> <listmail@joeware.net>


To:

ActiveDir@mail.activedir.org


Date:

01/02/2009 03:11 PM


Subject:

RE: [ActiveDir] RODC and computer accounts that are allowed to have their
creds replicated.


Sent by:

ActiveDir-owner@mail.activedir.org



_____




Here is the round about answer to your second question. :)

dn:CN=Denied RODC Password Replication Group,CN=Users,DC=trouble,DC=loc
>member: CN=Read-only Domain Controllers,CN=Users,DC=trouble,DC=loc
>member: CN=Group Policy Creator Owners,CN=Users,DC=trouble,DC=loc
>member: CN=Domain Admins,CN=Users,DC=trouble,DC=loc
>member: CN=Cert Publishers,CN=Users,DC=trouble,DC=loc
>member: CN=Enterprise Admins,CN=Users,DC=trouble,DC=loc
>member: CN=Schema Admins,CN=Users,DC=trouble,DC=loc
>member: CN=Domain Controllers,CN=Users,DC=trouble,DC=loc
>member: CN=krbtgt,CN=Users,DC=trouble,DC=loc


--
O'Reilly Active Directory Fourth Edition -
http://www.joeware.net/win/ad4e.htm



_____

From: ActiveDir-owner@mail.activedir.org
[mailto:ActiveDir-owner@mail.activedir.org] On Behalf Of Tony Gordon
Sent: Friday, January 02, 2009 3:36 PM
To: ActiveDir@mail.activedir.org
Subject: [ActiveDir] RODC and computer accounts that are allowed to have
their creds replicated.


We are planning to deploy RODCs to the regional offices. We have a
relatively painless way to automatically populate the groups that allow
"caching" the creds with the user accounts for each RODC. Computer
accounts present more of a challenge. One of the thoughts is to just put
domain computers group into the "Allowed RODC Password Replication" Group.

What are the specific risks we would be incurring in that scenario?

Is there a scenario where another DC (RO or RW) would auth to a particular
RODC and in doing so cause to have its password replicated to an RODC?

How did other people that deployed RODCs dealt with this issue.

Thank you, Tony.


Tony Gordon
Windows 2003 & 2000 MCSE, Windows 2003 MCSA, PMP
ITS Infrastructure Engineering
Hewitt Associates | 100 Half Day Road | Lincolnshire, IL 60069 | USA
Tel 847.295.5000 x50526 | Fax 847.554.1574
tony dot gordon at hewitt dot com | www.hewitt.com

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__________ Information from ESET Smart Security, version of virus signature
database 3739 (20090105) __________

The message was checked by ESET Smart Security.

http://www.eset.com


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