NOTE: This is not an exploit. This is not a
vulnerability. This is simply a bug that makes management of clients more
difficult / broken. Posting this to hopefully bring a bug in to the open that
may not have been discovered yet at companies other than my own. If this was a
flaw that allowed an exploit or if this allowed a system compromise then I would
not post this. If anyone knows of other virtual adapters that cause this problem
then I would appreciate emails listing the product and the MAC address that the
product uses.
---------------------------
I have a question for all of you about something I
noticed with Symantec AntiVirus Corporate Edition. The SAV CE client uses a GUID
(unique identifier) that is generated based on the MAC address of the Ethernet
adapter on the machine SAV CE is running on. This GUID is then used by
the SAV CE Parent Server that the managed client checks in to. If more than one machine has the same MAC address then in the
SSC (Symantec System Console) you will only see 1 machine even if 50 machines
have the same GUID and check in to the Parent. If you think that your SSC is
showing less clients than it should then you should possibly read this document
to see if this affects you. What I noticed was that this problem was not in my
corporate image at first but then it happened, and finally enough machines have
been replaced / reimaged that I noticed I was short on clients in the
SSC.
What is a GUID? Where is the GUID found? A GUID is
a Global Unique ID. Well at least it is supposed to be unique. It is found in
the key below. It is generated using a Microsoft library that is part of RPC. It
is based on the MAC address of an Ethernet adapter and your current IP address.
Is the IP address enough to make it unique even when the MAC is the same? I do
not know. I have been unable to find the answer. If the IP is enough to make
this value unique then remediation of this issue is as simple as deleting the
GUID key on all workstations that are not showing up in the SSC.
[HKEY_LOCAL_MACHINE\SOFTWARE\Intel\LANDesk\VirusProtect6\CurrentVersion] "GUID"=hex:3b,13,fe,fd,4c,6f,cc,4c,89,5b,82,1f,2b,c4,a0,43
How does SAV CE pick which adapter to make a GUID
from? It picks the first thing that looks like an Ethernet adapter by going
through the binding order in windows.
How can multiple machines end up with the same
GUID? Imagine a corporate standard image that might include the AOL client which
adds a hidden adapter to the system. Now when you ghost that image to a new
machine and the machine goes through sysprep it will add the Ethernet card of
the machine you are putting your image on. Since the AOL adapter never goes away
then the AOL adapter of course comes before the real Ethernet adapter. This
means that if the AOL adapter was selected by SAV CE in the master image then no
new GUID will generate because the GUID only changes when an adapter is added or
removed. Since the AOL adapter never leaves then it has a good chance of coming
before real adapters in the binding order. If the AOL adapter was not selected
in the master image by the LocalMAC registry key then a GUID should be
generated when you image a new target machine because SAV CE sees that the
old adapter leaves the machine and then it will look to the binding order to
pick a new adapter. SAV CE hopes to get a real Ethernet card and a GUID should
be generated based on the MAC address. So this problem happens most when the AOL
Adapter is watched by SAV, and that never leaves so LocalMAC will always watch
it and a new GUID never is generated.
How can you see machines with duplicate GUIDs if
you think they are not showing up in your SSC? Delete the key below using
whatever you have like SMS / NetOctopus / etc. The GUID will regenerate and
maybe you won't have duplicate GUIDs, but if you are generating the GUID from
the AOL MAC address then the potential for duplicates continues to exist. Note
that you want to probably clear out all the host records in the SSC if you do
this because you will see duplicates because the GUID is how the SSC tracks
records, and it takes 30 days for a stale record to purge out of the SSC with
the current version of SAV CE.
[HKEY_LOCAL_MACHINE\SOFTWARE\Intel\LANDesk\VirusProtect6\CurrentVersion] "GUID"=hex:3b,13,fe,fd,4c,6f,cc,4c,89,5b,82,1f,2b,c4,a0,43
How can you know that you are using the AOL MAC
address instead of the real one? It would seem that AOL 7.x, 8.x, and 9.x all
use 00-03-8a-00-00-15 as the MAC address for the virtual adapter. This aparently
is the pseudo-VPN adapter used when you connect to AOL over IP. Deleting this
key and rebooting will simply result in the same MAC address being tracked
because the AOL adapter will still come first in the binding list. The binding
list is from Windows binding order, and not anything from Symantec.
[HKEY_LOCAL_MACHINE\SOFTWARE\Intel\LANDesk\VirusProtect6\CurrentVersion]
"LocalMAC"=hex:00,03,8a,00,00,15
Can't I just change the binding order in Properties
for My Network Places in the Advanced Options? No. The AOL adapter does not
appear there for AOL 7.x, 8.x and 9.x. The adapter does not exist like it did in
AOL 6.x. The only way to remove the adapter is to uninstall AOL, and even then
if you re-install AOL it appears that it can come first again in the binding
order. You will get a new GUID, but since it is based on the AOL MAC addres then
it is possibly you will get a duplicate GUID again.
Doesn't the Parent Server resolve GUID conflicts
and tell a client to make a new one if there is a conflict? No. Because the GUID
is based on the MAC address, and the MAC address should never be the same from
machine to machine, the Parent Server does not do conflict resolution of GUIDs.
I am filing this idea as a RFE however with Symantec because if the server
simply did this then it would fix issues with other adapters.
Is this problem AOL's because of the adapter? No.
AOL is creating a virtual adapter just like a VPN client might. In concept what
AOL is doing is fine. The potential for this problem with other pre-loaded
software on a master image is great if that software makes a virtual adapter. In
fact if your company pre-loads VPN software or such then I would encourage you
to look at the LocalMAC value listed above and see if it matches your real
Ethernet adapter that you can see by going to Start -> Run and typing "cmd /k
ipconfig /all"
What versions of SAV CE does this affect, and what
operating systems? It affects everything from NAV 7.61 through SAV 8.1.1 that
I've looked at, and has the same problem on Windows 2000 and XP. It appears to
be a universal problem. (Windows NT and 98 were not looked at because they are
dead products.)
Is this problem Symantec's because they bind to a
VPN adapter? Sort of but not really. Symantec could have tested for more things
like default route or adapter able to reach the Parent server when doing the
figuring out, but they seem to have a pretty good detection system. It
would seem to me that the burden is on Symantec to put in an exclusion for the
AOL MAC address just like any other adapter found to cause similar
problems.
How critical is this? It appears to be more of an
annoyance than anything else. If you turn on debugging on your clients then you
will see the clients check in with "mommy" and it seems like policies are
being communicated from the Parent servers to their children. So it makes it so
that you can't really tell if your environment is protected. Depending on how
you view this to be critical will make it more or less important to you.
What can you do to fix this? I opened a ticket with
Symantec Platinum support a week ago. They said they have not seen other
customers with this issue. They are working on it though and understand the
issue, but I think they might not be 100% on board with this being something for
Symantec to fix. If you find that this issue affects you then I encourage you to
open a ticket with Symantec so that they can find out if this affects more
people than just my 10,000 clients. While 10,000 is a nice big number, it is
only one company so it is understandable that Symantec would wonder why no other
incidents were filed. If you have this problem then it is urgent that you make a
ticket. If you do not have support and it would cost you money to make a ticket
then please just email me how many clients you have and what company you are
with, and I will tell Symantec so you do not have to pay for support on this
issue.
Should you be angry with Symantec about this? No.
Seriously. There's no way they could have seen this bug. I just wanted to post
this document out there so that perhaps more feedback could come in to the
Symantec support system so that perhaps the issue would be given the proper
treatment when it gets to the programming staff as a bugfix.
Should you be angry with AOL about this? No.
Seriously. They make a VPNish adapter to tunnel you in to the network. They do
everything in a pretty legitimate way, and because they use the same MAC address
from version to version it is pretty simple to code an exclusion for that MAC
address. One could argue that AOL should be using unique MAC addresses, but
imagine all the MAC addresses that would be burned up by every single install of
AOL on every OS using up a MAC address. It would be very wasteful.
--
Joshua Levitsky, MCSE, CISSP System Engineer Time Inc. Information Technology [5957 F27C 9C71 E9A7 274A 0447 C9B9 75A4 9B41 D4D1] |
- Re: [Full-Disclosure] Symantec AntiVirus and AOL Joshua Levitsky
- Re: [Full-Disclosure] Symantec AntiVirus and AOL Joshua Levitsky