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schaut

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LSA Shell

A box appears on the desktop of my laptop saying
LSA Shell (export version) encountered a problem, aand goes on tosay I should send a n error report to Microsoft.  I have done that several times, also installed several upgrades, but the message continues to appear.
What is this and how do I get rid of it?
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Currently there are 4 variants of Sasser worms (Sasser.A, Sasser.B, Sasser.C, Sasser.D) in the wild. You need to install the MS security patches to be protected against malware exploiting Windows vulnerabilities. In this case you need to install MS04-011:
http://www.microsoft.com/technet/security/bulletin/ms04-011.mspx

The problem is that while you download the patch your computer must connect to the internet. Because of that it can be infected while you try to protect it. So it's a good idea to have a personal firewall installed. If you have not then there is a little trick to avoid infection while downloading the patch: Goto the folder %SYSTEMROOT%\DEBUG and create a read-only file named DCPROMO.LOG. Now connect to the internet, download the patch and close the internet connection. Now delete the DCPROMO.LOG and install the patch.

If your computer was already infected and shows a reboot message then open a command line and type the command "shutdown -a" (without the quotes) and press enter. This will abort the shutdown that was caused by the crash of LSASS.EXE. But keep in mind that the crash of LSASS.EXE may result in system instability and may prevent istalling the patch and cleaning the system. Because of that it's better to mitigate the vulnerability by using the workaround mentioned above.

Some additional explanation about the Sasser worms: In summary this worm and its variants exploit vulnerabilies in operating systems Windows 2000/XP/Server 2003 that do not have the security patch MS04-011 installed. The worm does not use email or websites to infect other computers. It does directly infect a computer that is connected to the internet. As part of the exploit the process LSASS.EXE may crash wich can cause the visible symptom with the message about LSA Shell (Export Version).

To remove Sasser from your system you can use the removal descriptions in the links mentioned below. Or you can use one of the following removal tools:
McAfee: http://vil.nai.com/vil/stinger
Symantec: http://www.sarc.com/avcenter/venc/data/w32.sasser.removal.tool.html
Trend Micro: http://www.trendmicro.com/download/dcs.asp

To prevent similar problems in the future I would recommend to protect internet connected computers with all available MS-patches. MBSA 1.2 (Microsoft Baseline Security Analyzer) is a free application that is able to check your computer whether all necessary patches are installed or not. If not it will list these patches. In addition there will be a link to the corresponding security bulletin where you can download the patch. Running MBSA once a week will make sure that your computer is up to date.

Link to MBSA: http://support.microsoft.com/?kbid=320454

Virus information about Sasser.A:
CA: http://www3.ca.com/threatinfo/virusinfo/virus.aspx?id=39012
McAfee: http://vil.nai.com/vil/content/v_125007.htm
Sophos: http://www.sophos.com/virusinfo/analyses/w32sassera.html
Symantec: http://www.symantec.com/avcenter/venc/data/w32.sasser.worm.html
Trend Micro: http://www.trendmicro.com/vinfo/virusencyclo/default5.asp?VName=WORM_SASSER.A


Virus information about Sasser.B:
CA: http://www3.ca.com/threatinfo/virusinfo/virus.aspx?id=39021
McAfee: http://vil.nai.com/vil/content/v_125008.htm
Sophos: http://www.sophos.com/virusinfo/analyses/w32sasserb.html
Symantec: http://www.symantec.com/avcenter/venc/data/w32.sasser.b.worm.html
Trend Micro: http://www.trendmicro.com/vinfo/virusencyclo/default5.asp?VName=WORM_SASSER.B


Virus information about Sasser.C:
CA: http://www3.ca.com/threatinfo/virusinfo/virus.aspx?id=39025
McAfee: http://vil.nai.com/vil/content/v_125009.htm
Symantec: http://www.symantec.com/avcenter/venc/data/w32.sasser.c.worm.html
Trend Micro: http://www.trendmicro.com/vinfo/virusencyclo/default5.asp?VName=WORM_SASSER.C

Virus information about Sasser.D:
CA: http://www3.ca.com/threatinfo/virusinfo/virus.aspx?id=39037
McAfee: http://vil.nai.com/vil/content/v_125012.htm
Symantec: http://www.symantec.com/avcenter/venc/data/w32.sasser.d.html
Trend Micro: http://www.trendmicro.com/vinfo/virusencyclo/default5.asp?VName=WORM_SASSER.D