Information Store unavailable but IS is running

I had to reboot four of our Exchange servers this morning because noone could connect to mail.  They all showed the same symptoms.  The IS was running but inaccessible from System Manager, which gave and event id of c1041721.  Last night we saw a Dr. Watson error in the app log.  Event ID 4097 regarding svchost.exe.  Since that error, we received an error generated by the SA every five minutes, indicating that the MAD monitoring thread was unable to connect to WMI...

Incidentally, we are running Symantect Antivirus for Exchange and have been deleting a large number of viruses...

Does anyone have any idea what might have happened.  So far the reboot has fixed it, but any recurrence of this issue will be a major problem

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You need to apply the security patch for MS03-026

MS03-026: Buffer Overrun in RPC May Allow Code Execution

You need to get this patch on ALL machines ASAP!!

This is the RPC vulnerability that the MSBlaster virus was taking advantage of. I have seen your exact issue 100 times now.

The RPC vulnerability is allowing the attacker to utilize port 135 and kill the svchost (RPC) service, which then terminates any use of the Event Viewer, Services, MAPI connectivity, etc. etc.

Get this patch on all machines ASAP, then run the MSBlaster removal tool on all machines to ensure the virus is not actually sitting somewhere.

You can get the removal tool for free from just about any AV website....

Once you get this patch applied and the removal tool run, you will be good to go!

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