-----Original Message-----
From: full-disclosure-bounces () lists grok org uk
[mailto:full-disclosure- bounces () lists grok org uk] On Behalf Of
George Carlson
Sent: Friday, December 10, 2010 10:12 AM
To: bugtraq () securityfocus com; full-disclosure () lists grok org uk
Subject: Re: [Full-disclosure] Flaw in Microsoft Domain Account
Caching Allows Local Workstation Admins to Temporarily Escalate
Privileges and Login as Cached Domain Admin Accounts (2010-M$-002)
Your objections are mostly true in a normal sense. However, it is not
true when Group Policy is taken into account. Group Policies
differentiate between local and Domain administrators and so this
vulnerability is problematic for shops that differentiate between
desktop support and AD support.
George Carlson
Sr. Network Engineer
(804) 423-7430
-----Original Message-----
From: Stefan Kanthak [mailto:stefan.kanthak () nexgo de]
Sent: Friday, December 10, 2010 11:30 AM
To: bugtraq () securityfocus com; full-disclosure () lists grok org uk
Cc: stenoplasma () exploitdevelopment com
Subject: Re: Flaw in Microsoft Domain Account Caching Allows Local
Workstation Admins to Temporarily Escalate Privileges and Login as
Cached Domain Admin Accounts (2010-M$-002)
"StenoPlasma @ www.ExploitDevelopment.com" wrote:
Much ado about nothing!
TITLE:
Flaw in Microsoft Domain Account Caching Allows Local Workstation
Admins to Temporarily Escalate Privileges and Login as Cached Domain
Admin Accounts
There is NO privilege escalation. A local administrator is an
admistrator is an administrator...
SUMMARY AND IMPACT:
All versions of Microsoft Windows operating systems allow real-time
modifications to the Active Directory cached accounts listing stored
on all Active Directory domain workstations and servers. This allows
domain users that have local administrator privileges on domain
assets to modify their cached accounts to masquerade as other domain
users that have logged in to those domain assets. This will allow
local administrators to temporarily escalate their domain privileges
on domain workstations or servers.
Wrong. The local administrator is already local administrator. There's
nothing the elevate any more.
If the local administrator masquerades as an Active Directory Domain
Admin account, the modified cached account is now free to modify
system files and user account profiles using the identity of the
Domain Admin's account.
There is no need to masquerade: the local administrator can perform
all these modifications, and if s/he wishes, hide the tracks: turn off
auditing before, clear audit/event logs afterwards, change the SID in
the ACEs of all objects touched (SubInACL.Exe comes handy), ...
Or: just change the "NoDefaultAdminOwner" setting. After that, all
"Administrators" masquerade as "Administrators". uh-oh.
This includes
creating scripts to run as the Domain Admin account the next time
that they log in.
Ridiculous.
A local administrator can add any script/executable s/he wants to any
"autostart" (scheduled task, registry, logon script, userinit, shell, ...).
There's ABSOLUTELY no need to masquerade.
All files created will not be linked to your domain account in file
and folder access lists.
ACEs can always be edited by a local administrator, see SubInACL.Exe,
or TakeOwn.Exe.
All security access lists
will only show the Domain Admin's account once you log out of the
modified cached account. This leads to a number of security issues
that I will not attempt to identify in the article. One major issue
is the lack of non-repudiation. Editing files and other actions will
be completed as another user account. Event log entries for object
access will only be created if administrators are auditing
successful access to files (This will lead to enormous event log sizes).
A local administrator can turn audit/event logs off, clear or modify them.
Stefan
_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/
