RE: Threat vector of running a service using a domain account

["Roger A. Grimes" <roger () banneretcs com>]

Yes, I'm confusing my dumps. Service account passwords, which I think
the original poster was inquiring about, dumps from memory using
lsadump.  Cachedumps are for local logon password dumps. 

Lsadumps retrieve the passwords in plaintext (each char. separated by a
. character).

Cachedump, which again, doesn't work so well against the latest versions
of the Windows OS does dump the locally stored logon cached passwords.
However, they are far from plaintext. The retrieved hashes are even
stronger than the normally "hard to crack" NT hashes. I can retrieve the
hashes fairly easily (logged in as local admin on an older version of
Windows), but converting them from their hashed form is difficult. If
the password is longer than 8 characters, a brute force method most
likely won't work anytime soon. And there aren't any Rainbow tables for
password hash cache dumps as far as I know.

So, unless your admin logon passwords are weak, extracting the logon
hashes alone isn't that helpful, whereas, using lsadump has helped me
privilege escalate from local admin to Enterprise Admin in a few minutes
many times.

Of course the far bigger threat to any environment is nearly any other
sort of client-side attack you can randomly think of.

Roger

*****************************************************************
*Roger A. Grimes, InfoWorld, Security Columnist 
*CPA, CISSP, CISA, MCSE: Security (2000/2003), CEH, yada...yada...
*email: roger_grimes () infoworld com or roger () banneretcs com
*Author of Windows Vista Security: Securing Vista Against Malicious
Attacks (Wiley)
*http://www.amazon.com/Windows-Vista-Security-Securing-Malicious/dp/0470
101555
*****************************************************************


-----Original Message-----
From: listbounce () securityfocus com [mailto:listbounce () securityfocus com]
On Behalf Of Ramsdell, Scott
Sent: Friday, September 14, 2007 3:35 PM
To: Roger A. Grimes; Ali, Saqib; Jay
Cc: smanaois3 () gmail com; security-basics () securityfocus com
Subject: RE: Threat vector of running a service using a domain account

> From recollection, cachedump grabs the hashes that have been stored in
the registry.

It is persistent across reboots therefore, and effected by the "Number
of logons to cache" setting in AD.

I've used cachedump to demonstrate why the Helpdesk shouldn't login to
user's workstations with domain admin creds, when the users themselves
are local admins.

Kind Regards,
Scott Ramsdell


-----Original Message-----
From: Roger A. Grimes [mailto:roger () banneretcs com]
Sent: Friday, September 14, 2007 2:25 PM
To: Ramsdell, Scott; Ali, Saqib; Jay
Cc: smanaois3 () gmail com; security-basics () securityfocus com
Subject: RE: Threat vector of running a service using a domain account

I'm not sure...so I'm just spectulating...but

All service account passwords are stored locally in the LSA secrets
store. 

Cachedump only works locally against the cached passwords, left in
MEMORY to facilitate service authentications.  You can't get to the
truly stored hashes on the disk because they are protected by a secure
mechanism, so you have to get them in the memory cache area.  I'm
guessing that the real hash is stored securely.  When the service starts
up and uses a Kerberos account, the pre-auth hash is sent, and in memory
briefly. But after the pre-auth handshake, what is kept in memory is the
Kerberos token, which is now used for all future auth. needs for the
next 10 hours or more.

I could, and may be wrong. 

Roger

*****************************************************************
*Roger A. Grimes, InfoWorld, Security Columnist *CPA, CISSP, CISA, MCSE:
Security (2000/2003), CEH, yada...yada...
*email: roger_grimes () infoworld com or roger () banneretcs com *Author of
Windows Vista Security: Securing Vista Against Malicious Attacks (Wiley)
*http://www.amazon.com/Windows-Vista-Security-Securing-Malicious/dp/0470
101555
*****************************************************************


-----Original Message-----
From: listbounce () securityfocus com [mailto:listbounce () securityfocus com]
On Behalf Of Ramsdell, Scott
Sent: Friday, September 14, 2007 9:01 AM
To: Ali, Saqib; Jay
Cc: smanaois3 () gmail com; security-basics () securityfocus com
Subject: RE: Threat vector of running a service using a domain account

Saqib,

I believe you're right.  Each time I've run cachedump for demonstration
I do not receive hashes for services logging in over the network, I only
receive hashes for interactive users.

Kind Regards,
Scott Ramsdell

-----Original Message-----
From: listbounce () securityfocus com [mailto:listbounce () securityfocus com]
On Behalf Of Ali, Saqib
Sent: Thursday, September 13, 2007 12:42 PM
To: Jay
Cc: smanaois3 () gmail com; security-basics () securityfocus com
Subject: Re: Threat vector of running a service using a domain account

> If a server does cache these creditonals then these can be attacked
independant of the AD and its underlying security controls.


If a service uses domain credential, do those credentials get cached?
I thought only interactive logon credentials are cached.

saqib
http://security-basics.blogspot.com/