Re: Why does the lsass.exe process use so much CPU?

Thanks for the prompt advice. I'm working on following your suggestions now
and will post back my results here.

Eric Kolotyluk
Software Developer

"Leonard Grey" wrote:

Your computer is most likely infected.

&ry scanning your system with /several/ of the better online scanners,
such as:
Kaspersky Antivirus (
Panda ActiveScan (

Download HijackThis from Run it, save a log, and
post the log at one of the many sites that support HJT, such as,, and -- but not
here. Within a day, sometimes within an hour, you'll have one-on-one
step-by-step advice from a security expert on cleaning up any
infestations—or you'll have a clean bill of health from the volunteer

Even the best detection and removal software can't fix every malware
infection. If none of the above remove the infection, you may want to
show the computer to a professional.

Leonard Grey
Errare humanum est

"A Day in the Life of a Web 2.0 Hacker" - PC Magazine,2817,2330952,00.asp

Eric Kolotyluk wrote:
I'm using XP SP3 on my computer at home. A few weeks ago I noticed my
computer was using a significant amount of CPU even though no applications
were running. Using task manager I discovered that lsass.exe was using 30 % -
50% of my CPU constantly. I have never seen this behavior before. Overall
performance on my computer has been abysmal since then.

Is there any valid reason why this process is using so much CPU?

I've browsed the web and found lots of articles on viruses using lsass.exe
as as vector, but nothing the seems to be helpful. Using Process Explorer I
tried to validate the process, and Process Explore thinks it's a valid
Microsoft process.

I've been in touch with Bit Defender, my security software provider, but
they have not really been of use.

I'm still convinced there is something not quite right with my system, but
the virus scans don't turn up anything. I have notice the for some reason the
latest Windows updates seem to fail. My disk keeps getting full even though I
am not adding any files, and routinely cleaning out temporary and cache files.

Any help or thoughts would be greatly appreciated.