LSASS.EXE consuming excessive CPU on 2003 server


I have an issue with one of my client site.

They have 2 DC's (2003 server). The first DC having some issues with LSASS.EXE consuming excessive CPU and the server is locking up. To bring the server, we need to unplug the n/w cable or reboot the server. It will be ok for few minutes and happening again.
So far, i have followed the steps;

1) Checked for virus, installed MS malicious removal tool but couldn't find any infection

2) Tried to install this hostfix but it says, already running with latest SP, so couldn't install.

3) Installed this hotfix and rebooted the server, unfortunately after the reboot, the CPU usage became 100%.

I couldn't find any errors in event logs. This is really driving me crazy.

Any advise would be much appriaciated.
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Radhakrishnan RSenior Technical LeadAsked:
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I believe you are running windows 2003 SP2. Please check all recent patches and updates are updated.

Some Lsass.exe related recent hot fixes which will update the files to recent version


Also check what version Lsass.exe there in the server and check and update it to latest version.
Radhakrishnan RSenior Technical LeadAuthor Commented:

Thanks, i'll have a look and get back to you.
SandeshdubeySenior Server EngineerCommented:
Troubleshooting High LSASS CPU Utilization on a Domain Controller (Part 1 of 2)

Troubleshooting High CPU Utilization issues using Tracelog.exe

In addition I would also recommend to disable Antivirus and security application if any installed on DC and reboot the server and check also ensure that latest hotfix and SP is installed on the server .

Process explore:
Hope this helps
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Radhakrishnan RSenior Technical LeadAuthor Commented:

I had tried to install the hotfixes but 2 of them couldn't install as it said already SP2 installed, hence it's not required. Rebooted the server, as soon as i logged in, the CPU utilization went 100%.

Already i had installed process explore and wireshark, from this only i had found lsass.exe comsuming 100% CPU but couldn't find the reason why?

I have advised my client to shut down all of their computers, once the machines were shutdown, the CPU utilization came to 9 - 10% (wondering).

Started one batch of (20 machines) machines, immediately the CPU utilization reached 100%. This should have happened even if i reboot another batch of machines.

I suspect that there is something causing from the client side. Could be a virus but MS malicious removal or Malware bite didn't catch any infections.

This is bit challenging and critical issue for me now, as my client stopped one of my payment and asked to resolve the issue first.

Any more ideas?
SandeshdubeySenior Server EngineerCommented:
I will recommend to scan the computer with latest AV and also installed hotfix too.This could be due to virus issue.Virus like conflicker can cause banswidth choke,etc.Take first couple of computer out of network install hofix and scan and perform the test and check how does it work.

Also ensure that there is no addition app,thirdy party software/application installed on DC.

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Radhakrishnan RSenior Technical LeadAuthor Commented:
Hi Sandeshdubey,

Thanks for your prompt reply.

There are plenty of 3rd party applications running on the DC. Already i had advised them to remove the 3rd party applications from the DC but they said that it's required for them and it's running from past few years.

However, as a testing purpose, i'll uninstall and let you know :)
Radhakrishnan RSenior Technical LeadAuthor Commented:

Further update:-

Uninstalled most of the 3rd party application on the server but the issue still persists.

Also, performed sfc /scannow which finished without any issues but still the lsass.exe consuming high cpu.

Re-registered all the dll's in system32 folder, rebooted the server, it was ok for few minutes, the CPU usage went 100% as soon as the users started log in.

It seems to be some kind relation between user authentication (kerberos) but couldn't figure it out.

Any help would be much appriciated.
SandeshdubeySenior Server EngineerCommented:
Have you check event log on DC are you getting any errors and warming message?

As you have two Dcs, if you shut this problematic DC.Does the issue occur on other DC,do client face any authentication issue?
SandeshdubeySenior Server EngineerCommented:
In addition if the other DC is good and clients are not facing issue.Take the backup of problematic server related data,app,etc as per requirement.Clean the OS/format and reload the OS and add the server back as DC.

Also dont install the application/thirdy pary software on DC it should be on member server.
Radhakrishnan RSenior Technical LeadAuthor Commented:

Finally, i have fixed the issue. It was due to a 3rd party application called "Impero" (some monitoring software).

I performed a netstat -ano and tracked down the PID for lsass.exe and checked which computers are getting more connections.

Disabled the non MS services one by one and found that the CPU usage went down as soon as i disabled the Impero services.

It has been disabled via GPO for globally and everything seems to be fine at the moment.

Thanks for your help in this matter.
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Windows Server 2003

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