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Re: Flaw in Microsoft Domain Account Caching Allows Local Workstation Admins to Temporarily Escalate Privileges and Login as Cached Domain Admin Accounts (2010-M$-002)


From: phil () jabea net
Date: Mon, 13 Dec 2010 09:37:49 -0500

If a bad guy got the local admin password, then the computer is in it's
control at 100%. No need to run script as a domain user, as the local
admin can already format the drive, or remove all security mesure.

The cached credential is a hash of a hash. (kinda long to crack)

Any good network admin would use a account that can only join a computer
in the domain, and use the local admin account to install software or a
helpdesk account that got local admin right.

The only case maybe that case is a security hole that I can think of, I
told maybe because I didn't tested it. It's if the computer got a local
mssql with mixed mode authentification. Does the trick permit the login to
the database if you installed it with a domain user, that is cached on the
computer? (But who care, as the local admin can just copy the data dir
anyway)


My .02 cent



-phil


Correct me if I'm wrong, but here is what I think of that :

A Domain user that is a Local admin of his workstation is different than
a Domain user which is Domain Admin.

Then, a local admin whose account is an AD account can run scripts *on
his local machine* in the name of the domain admin.

This includes the possibility of dumping the Domain Admin password hash
and even *all the domain accounts password hashes* (ie: psexec + pwdump
against the DC, with the privileges of the domain admin).

An exploitation scenario could be the following for an unprivileged
domain user:

- Become local admin of his workstation (bunch of methods out there)
- Run script ad the Domain Admin with this technique)
- Recover Domain admin or Domain Users password hashes.
- Crack the passwords and become Domain Admin (ie: Administrator of all
workstations and servers in the domain).

My two cents !

J-


On 10/12/2010 15:37, Jeffrey Walton wrote:
On Thu, Dec 9, 2010 at 10:07 PM, Thor (Hammer of God)
<thor () hammerofgod com>  wrote:
What do you mean by "regular local administrator"?  You're a local
admin,
or you're not.
I believe the OP's intent was to differentiate between Local
Administrators and Domain (or Enterprise) Administrators. Corrections
from StenoPlasma are welcomed.

There are not degrees of local admin.
But there are different accounts, both domain and local, which have
administrator rights and privileges on the local machine.

[SNIP]

Jeff

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