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

["Ramsdell, Scott" <Scott.Ramsdell () cellnet com>]

Saqib,

AD will allow you to mitigate the risk by specifying that the account
can only login to the appropriate server(s).  I assume you knew that,
but it wasn't mentioned, so I'll throw it out there.

Each time I encountered a vendor that suggested their app required
domain admin privs, they were wrong.  They actually required admin privs
on certain boxes (and that was debatable).

So, I made it a habit to create a group named LocalAdminsServerX on the
DC, and placed that group in ServerX's local admins group.  When a
service account required admin privs on a box, I'd drop it into the
LocalAdmin group appropriate for the server(s) it needed admin access
to.

This prevented the account from doing what it needed to without being a
domain admin.  Of course, this won't work for services that need to run
on a domain controller.  This solution also allows you to control local
admins from AD, as you can monitor changes to the local admins group on
your servers and alert if a change is made.

Likely, it would be possible to narrow down with the vendor what
access/privs were actually required and grant appropriate permissions,
rather than accept the default vendor response "it requires domain admin
privs".  If it isn't creating users, adding machines to the domain,
managing AD, etc. then it doesn't require domain admin privs.

These suggestions mostly speak to your (5) below, as to your (3), "yes"
it is very common for a vendor to not worry at all about their
suggestion to you to grant their app full rights within your AD tree.
After all, it makes it very easy for them.

Kind Regards,
Scott Ramsdell

-----Original Message-----
From: listbounce () securityfocus com [mailto:listbounce () securityfocus com]
On Behalf Of Ali, Saqib
Sent: Sunday, September 09, 2007 10:44 PM
To: security-basics
Subject: Threat vector of running a service using a domain account

i would like to understand the threat vector of using a "dedicated"
Active Directory account to run a service. Here are some details:

1) This particular account will have domain admin privileges.
2) The account will NOT be used to perform interactive logon to the
machines.
3) The password for the account will be stored in a safe-box

The brute-force attack risk is mitigated by the fact that the account
will lockout after X number of unsuccessful attempt. Also any attempt
to use the account for interactive logon will show up in the audit
logs.

My questions:
1) Is the risk manageable?
2) Or should we completely avoid this application?
3) Is this kind of scenario common?
4) What other popular apps require such domain admin privileges for
service accounts?
5) What other Controls can we put in place to prevent misuse of the
account?

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