Trojan.Tooso.N

1. Creates the following file:
   
   %Windir%\gfgdgfddfgdfgwe.exe
   
   Note: %Windir% is a variable that refers to the Windows installation folder. By default, this is C:\Windows or C:\Winnt.
   
   
2. Attempts to execute this file, which only runs under Windows 95/98/Me.
   
   Note: If the compromised computer is not running Windows 95/98/Me, the Trojan will not execute.
   
   
3. Copies itself as %System%\winshost.exe.
   
   Note: %System% is a variable that refers to the System folder. By default this is C:\Windows\System (Windows 95/98/Me), C:\Winnt\System32 (Windows NT/2000), or C:\Windows\System32 (Windows XP).
   
   
4. Drops the following file:
   
   %System%\wiwshost.exe
   
   
5. Adds the value:
   
   "winshost.exe" = "%System%\winshost.exe"
   
   to the registry entries:
   
   HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
   
   so that it runs every time Windows starts.
   
   
6. Attempts to find the explorer.exe process and injects wiwshost.exe into it.
   
   Note: All subsequent actions are taken by wiwshost.exe, but will appear to be taken by explorer.exe.
   
   
7. Overwrites the compromised computer's hosts file with the following text:
   
   127.0.0.1 localhost
   
   
8. Launches a thread that stops services with the following names:
   
   
   • Ahnlab task Scheduler
   • alerter
   • AlertManger
   • AVExch32Service
   • avg7alrt
   • avg7updsvc
   • AvgCore
   • AvgFsh
   • AvgServ
   • avpcc
   • AVPCC
   • AVUPDService
   • AvxIni
   • awhost32
   • backweb client - 4476822
   • BackWeb Client - 7681197
   • backweb client-4476822
   • BlackICE
   • CAISafe
   • ccEvtMgr
   • ccEvtMgr
   • ccPwdSvc
   • ccSetMgr
   • ccSetMgr.exe
   • DefWatch
   • dvpapi
   • dvpinit
   • fsbwsys
   • fsdfwd
   • FSDFWD
   • F-Secure Gatekeeper Handler Starter
   • F-Secure Gatekeeper Handler Starter
   • FSMA
   • FSMA
   • KAVMonitorService
   • KAVMonitorService
   • kavsvc
   • KLBLMain
   • McAfee Firewall
   • McAfeeFramework
   • McShield
   • McTaskManager
   • mcupdmgr.exe
   • MCVSRte
   • MonSvcNT
   • navapsvc
   • navapsvc
   • navapsvc
   • navapsvc
   • Network Associates Log Service
   • NISSERV
   • NISUM
   • NOD32ControlCenter
   • NOD32Service
   • Norman NJeeves
   • Norman ZANDA
   • Norton Antivirus Server
   • NPFMntor
   • NProtectService
   • NSCTOP
   • nvcoas
   • NVCScheduler
   • nwclntc
   • nwclntd
   • nwclnte
   • nwclntf
   • nwclntg
   • nwclnth
   • NWService
   • Outbreak Manager
   • Outpost Firewall
   • OutpostFirewall
   • PASSRV
   • PAVFNSVR
   • Pavkre
   • PavProt
   • PavPrSrv
   • PAVSRV
   • PCCPFW
   • PersFW
   • PREVSRV
   • PSIMSVC
   • ravmon8
   • SAVFMSE
   • SAVScan
   • SAVScan
   • SAVScan
   • SBService
   • schscnt
   • SharedAccess
   • sharedaccess
   • SharedAccess
   • SmcService
   • SNDSrvc
   • SPBBCSvc
   • SweepNet
   • SWEEPSRV.SYS
   • Symantec AntiVirus Client
   • Symantec Core LC
   • Symantec Core LC
   • Symantec Core LC
   • Tmntsrv
   • V3MonNT
   • V3MonSvc
   • VexiraAntivirus
   • VisNetic AntiVirus Plug-in
   • vsmon
   • vsmon
   • wscsvc
   • wuauserv
   • wuauserv
   • XCOMM
     
     
9. Attempts to delete the following registry entries:
   
   "Symantec NetDriver Monitor"
   "ccApp"
   "NAV CfgWiz"
   "SSC_UserPrompt"
   "McAfee Guardian"
   "APVXDWIN"
   "KAV50"
   "avg7_cc"
   "avg7_emc"
   "Zone Labs Client"
   
   from the following subkey:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
   
   
10. Attempts to delete the following registry entry:
    
    "McAfee.InstantUpdate.Monitor"
    
    from the following subkey:
    
    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    
    
11. Attempts to delete the following registry subkeys:
    
    HKEY_LOCAL_MACHINE\SOFTWARE\Symantec
    HKEY_LOCAL_MACHINE\SOFTWARE\McAfee
    HKEY_LOCAL_MACHINE\SOFTWARE\KasperskyLab
    HKEY_LOCAL_MACHINE\SOFTWARE\Agnitum
    HKEY_LOCAL_MACHINE\SOFTWARE\Panda Software
    HKEY_LOCAL_MACHINE\SOFTWARE\Zone Labs
    
    
12. Attempts to rename all instances of the following files on all fixed drives:
    
    Renamed from:
    
    
    • av.dll to a5v.dll
    • AUPDATE.EXE to AUPD1ATE.EXE
    • Avsynmgr.exe to Av1synmgr.exe
    • Avconsol.exe to Avc1onsol.exe
    • avgemc.exe to avg23emc.exe
    • avgcc.exe to avgc3c.exe
    • CCSETMGR.EXE to C1CSETMGR.EXE
    • cafix.exe to c6a5fix.exe
    • CCEVTMGR.EXE to CC1EVTMGR.EXE
    • ccl30.dll to cc1l30.dll
    • ccApp.exe to ccA1pp.exe
    • ccvrtrst.dll to ccv1rtrst.dll
    • CMGrdian.exe to CM1Grdian.exe
    • isafe.exe to is5a6fe.exe
    • KAV.exe to K2A2V.exe
    • kavmm.exe to kav12mm.exe
    • LUALL.EXE to LUAL1L.EXE
    • LUINSDLL.DLL to LUI1NSDLL.DLL
    • Luupdate.exe to Luup1date.exe
    • Mcshield.exe to Mcsh1ield.exe
    • NAVAPSVC.EXE to NAV1APSVC.EXE
    • NPFMNTOR.EXE to NPFM1NTOR.EXE
    • outpost.exe to outp1ost.exe
    • RuLaunch.exe to RuLa1unch.exe
    • symlcsvc.exe to s1ymlcsvc.exe
    • SNDSrvc.exe to SND1Srvc.exe
    • SPBBCSvc.exe to SP1BBCSvc.exe
    • Up2Date.exe to Up222Date.exe
    • vetredir.dll to ve6tre5dir.dll
    • VsStat.exe to Vs1Stat.exe
    • vsvault.dll to vs6va5ult.dll
    • Vshwin32.exe to Vshw1in32.exe
    • zatutor.exe to zatu6tor.exe
    • zlavscan.dll to zl5avscan.dll
    • zlclient.exe to zlcli6ent.exe
    • zonealarm.exe to zo3nealarm.exe
      
      
13. Attempts to terminate processes with the following names:
    
    
    • ATUPDATER.EXE
    • ATUPDATER.EXE
    • AUPDATE.EXE
    • AUTODOWN.EXE
    • AUTOTRACE.EXE
    • AUTOUPDATE.EXE
    • AVPUPD.EXE
    • AVWUPD32.EXE
    • AVXQUAR.EXE
    • AVXQUAR.EXE
    • CFIAUDIT.EXE
    • DRWEBUPW.EXE
    • ESCANH95.EXE
    • ESCANHNT.EXE
    • FIREWALL.EXE
    • ICSSUPPNT.EXE
    • ICSUPP95.EXE
    • LUALL.EXE
    • MCUPDATE.EXE
    • NUPGRADE.EXE
    • NUPGRADE.EXE
    • OUTPOST.EXE
    • UPDATE.EXE
    • UPGRADER.EXE
      
      
14. Attempts to download files from the following URLs in the sequence given:
    
    
    • [http://]www.yannick-spruyt.be/[REMOVED]/osa5.gif
    • [http://]www.yayadownload.com/ [REMOVED]/osa5.gif
    • [http://]www.yesterdays.co.za/ [REMOVED]/osa5.gif
    • [http://]www.yesterdays.co.za/ [REMOVED]/osa5.gif
    • [http://]www.yshkj.com/[REMOVED]/osa5.gif
    • [http://]www.yshkj.com/[REMOVED]/osa5.gif
    • [http://]www.zakazcd.dp.ua/[REMOVED]/osa5.gif
    • [http://]www.students.stir.ac.uk/[REMOVED]/osa5.gif
    • [http://]www.zenesoftware.com/[REMOVED]/osa5.gif
    • [http://]www.zentek.co.za/[REMOVED]/osa5.gif
    • [http://]www.czzm.com/[REMOVED]/osa5.gif
    • [http://]www.izoli.sk/[REMOVED]/osa5.gif
    • [http://]www.zorbas.az/[REMOVED]/osa5.gif
    • [http://]www.zsbersala.edu.sk/[REMOVED]/osa5.gif
    • [http://]www.triptonic.ch/[REMOVED]/osa5.gif
    • [http://]www.tv-marina.com/[REMOVED]/osa5.gif
    • [http://]www.travelourway.com/[REMOVED]/osa5.gif
    • [http://]www.megaserve.net/[REMOVED]/osa5.gif
    • [http://]www.trgd.dobrcz.pl/[REMOVED]/osa5.gif
    • [http://]www.mild.at/[REMOVED]/osa5.gif
    • [http://]www.mild.at/[REMOVED]/osa5.gif
    • [http://]www.kingsley.ch/[REMOVED]/osa5.gif
    • [http://]www.mild.at/[REMOVED]/osa5.gif
    • [http://]www.elvis-presley.ch/[REMOVED]/osa5.gif
    • [http://]www.gomyhome.com.tw/[REMOVED]/osa5.gif
    • [http://]www.ider.cl/[REMOVED]/osa5.gif
    • [http://]www.ascolfibras.com/[REMOVED]/osa5.gif
    • [http://]www.on24.ee/[REMOVED]/osa5.gif
    • [http://]www.xojc.com/[REMOVED]/osa5.gif
    • [http://]www.x-treme.cz/[REMOVED]/osa5.gif
    • [http://]www.gymzn.cz/[REMOVED]/osa5.gif
    • [http://]www.gymzn.cz/[REMOVED]/osa5.gif
    • [http://]www.gymzn.cz/[REMOVED]/osa5.gif
    • [http://]www.xiantong.net/[REMOVED]/osa5.gif
    • [http://]www.xmpie.com/[REMOVED]/osa5.gif
    • [http://]www.xmpie.com/[REMOVED]/osa5.gif
    • [http://]www.xmtd.com/[REMOVED]/osa5.gif
    • [http://]www.onlink.net/[REMOVED]/osa5.gif
    • [http://]www.discoteka-funfactory.com/[REMOVED]/osa5.gif
    • [http://]www.toussain.be/[REMOVED]/osa5.gif
    • [http://]www.idcs.be/[REMOVED]/osa5.gif
    • [http://]www.gepeters.org/[REMOVED]/osa5.gif
    • [http://]www.angham.de/[REMOVED]/osa5.gif
    • [http://]www.idaf.de/[REMOVED]/osa5.gif
    • [http://]www.bolz.at/[REMOVED]/osa5.gif
    • [http://]www.societaet.de/[REMOVED]/osa5.gif
    • [http://]www.ppm-alliance.de/[REMOVED]/osa5.gif
    • [http://]www.udc-cassinadepecchi.it/[REMOVED]/osa5.gif
    • [http://]www.universe.sk/[REMOVED]/osa5.gif
    • [http://]www.jingjuok.com/[REMOVED]/osa5.gif
    • [http://]www.gemtrox.com.tw/[REMOVED]/osa5.gif
    • [http://]www.uspowerchair.com/[REMOVED]/osa5.gif
    • [http://]www.steripharm.com/[REMOVED]/osa5.gif
    • [http://]www.beall-cpa.com/[REMOVED]/osa5.gif
    • [http://]www.jcm-american.com/[REMOVED]/osa5.gif
    • [http://]www.vercruyssenelektro.be/[REMOVED]/osa5.gif
    • [http://]www.centrovestecasa.it/[REMOVED]/osa5.gif
    • [http://]www.vet24h.com/[REMOVED]/osa5.gif
    • [http://]www.vinimeloni.com/[REMOVED]/osa5.gif
    • [http://]www.vnrvjiet.ac.in/[REMOVED]/osa5.gif
    • [http://]www.vote2fateh.com/[REMOVED]/osa5.gif
    • [http://]www.marketvw.com/[REMOVED]/osa5.gif
    • [http://]www.formholz.at/[REMOVED]/osa5.gif
    • [http://]www.checkonemedia.nl/[REMOVED]/osa5.gif
    • [http://]www.fotomax.fi/[REMOVED]/osa5.gif
    • [http://]www.vw.press-bank.pl/[REMOVED]/osa5.gif
    • [http://]www.wamba.asn.au/[REMOVED]/osa5.gif
    • [http://]www.cz-wanjia.com/[REMOVED]/osa5.gif
    • [http://]www.czwanqing.com/[REMOVED]/osa5.gif
    • [http://]www.wdlp.co.za/[REMOVED]/osa5.gif
    • [http://]www.automobilonline.de/[REMOVED]/osa5.gif
    • [http://]www.bangyan.cn/[REMOVED]/osa5.gif
    • [http://]www.21ebuild.com/[REMOVED]/osa5.gif
    • [http://]www.eagle.com.cn/[REMOVED]/osa5.gif
    • [http://]www.eagleclub.com.cn/[REMOVED]/osa5.gif
    • [http://]www.eagleclub.com.cn/[REMOVED]/osa5.gif
    • [http://]www.sanjinyuan.com/[REMOVED]/osa5.gif
    • [http://]www.designgong.org/[REMOVED]/osa5.gif
    • [http://]www.fermegaroy.com/[REMOVED]/osa5.gif
    • [http://]www.welchcorp.com/[REMOVED]/osa5.gif
    • [http://]www.snsphoto.com/[REMOVED]/osa5.gif
    • [http://]www.soeco.org/[REMOVED]/osa5.gif
    • [http://]www.softmajor.ru/[REMOVED]/osa5.gif
    • [http://]www.solt3.org/[REMOVED]/osa5.gif
    • [http://]www.sqnsolutions.com/[REMOVED]/osa5.gif
    • [http://]www.spacium.biz/[REMOVED]/osa5.gif
    • [http://]www.speedcom.home.pl/[REMOVED]/osa5.gif
    • [http://]www.trago.com.pt/[REMOVED]/osa5.gif
    • [http://]www.spirit-in-steel.at/[REMOVED]/osa5.gif
    • [http://]www.spy.az/[REMOVED]/osa5.gif
    • [http://]www.st-paulus-bonn.dehtdocs/[REMOVED]/osa5.gif
    • [http://]www.stbs.com.hk/[REMOVED]/osa5.gif
    • [http://]www.acsohio.com/[REMOVED]/osa5.gif
    • [http://]www.olva.com.pe/[REMOVED]/osa5.gif
    • [http://]www.subsplanet.com/[REMOVED]/osa5.gif
    • [http://]www.sungodbio.com/[REMOVED]/osa5.gif
    • [http://]www.superbetcs.com/[REMOVED]/osa5.gif
    • [http://]www.vnn.vn/[REMOVED]/osa5.gif
    • [http://]www.sydolo.com/[REMOVED]/osa5.gif
    • [http://]www.szdiheng.com/[REMOVED]/osa5.gif
    • [http://]www.agria.hu/[REMOVED]/osa5.gif
    • [http://]www.externet.hu/[REMOVED]/osa5.gif
    • [http://]www.hondenservice.be/[REMOVED]/osa5.gif
    • [http://]www.ehc.hu/[REMOVED]/osa5.gif
    • [http://]www.tcicampus.net/[REMOVED]/osa5.gif
    • [http://]www.contentproject.com/[REMOVED]/osa5.gif
    • [http://]www.festivalteatrooccidente.com/[REMOVED]/osa5.gif
    • [http://]www.techni.com.cn/[REMOVED]/osa5.gif
    • [http://]www.festivalteatrooccidente.com/[REMOVED]/osa5.gif
    • [http://]www.thaifast.com/[REMOVED]/osa5.gif
    • [http://]www.thaiventure.com/[REMOVED]/osa5.gif
    • [http://]www.andi.com.vn/[REMOVED]/osa5.gif
    • [http://]www.replayu.com/[REMOVED]/osa5.gif
    • [http://]www.th-mutan.com/[REMOVED]/osa5.gif
    • [http://]www.thetexasoutfitter.com/[REMOVED]/osa5.gif
    • [http://]www.tmhcsd1987.friko.pl/[REMOVED]/osa5.gif
    • [http://]www.thenextstep.tv/[REMOVED]/osa5.gif
    • [http://]www.thenextstep.tv/[REMOVED]/osa5.gif
    • [http://]www.wesartproductions.com/[REMOVED]/osa5.gif
    • [http://]www.wilsonscountry.com/[REMOVED]/osa5.gif
    • [http://]www.windstar.pl/[REMOVED]/osa5.gif
    • [http://]www.wise-industries.com/[REMOVED]/osa5.gif
    • [http://]www.witold.pl/[REMOVED]/osa5.gif
    • [http://]www.witold.pl/[REMOVED]/osa5.gif
    • [http://]www.51.net/[REMOVED]/osa5.gif
    • [http://]www.slovanet.sk/[REMOVED]/osa5.gif
    • [http://]www.wombband.com/[REMOVED]/osa5.gif
    • [http://]www.datanet.huwww.datanet.hu/[REMOVED]/osa5.gif
    • [http://]www.uw.hu/[REMOVED]/osa5.gif
    • [http://]www.dgy.com.cn/[REMOVED]/osa5.gif
    • [http://]www.bs-security.de/[REMOVED]/osa5.gif
    • [http://]www.die-fliesen.de/[REMOVED]/osa5.gif
    • [http://]www.dom-invest.com.pl/[REMOVED]/osa5.gif
    • [http://]www.engelhardtgmbh.de/[REMOVED]/osa5.gif
    • [http://]www.triapex.cz/[REMOVED]/osa5.gif
    • [http://]www.fahrschule-herb.de/[REMOVED]/osa5.gif
    • [http://]www.fahrschule-lesser.de/[REMOVED]/osa5.gif
    • [http://]www.gimex-messzeuge.de/[REMOVED]/osa5.gif
    • [http://]www.inside-tgweb.de/[REMOVED]/osa5.gif
    • [http://]www.jue-bo.com/[REMOVED]/osa5.gif
    • [http://]www.niko.de/[REMOVED]/osa5.gif
    • [http://]www.nikogmbh.com/[REMOVED]/osa5.gif
    • [http://]www.renegaderc.com/[REMOVED]/osa5.gif
    • [http://]www.sachsenbuecher.de/[REMOVED]/osa5.gif
    • [http://]www.scvanravenswaaij.nl/[REMOVED]/osa5.gif
    • [http://]www.spoden.de/[REMOVED]/osa5.gif
    • [http://]www.sportnf.com/[REMOVED]/osa5.gif
    • [http://]www.sweb.cz/[REMOVED]/osa5.gif
    • [http://]www.tg-sandhausen-basketball.de/[REMOVED]/osa5.gif
    • [http://]www.thefunkiest.com/[REMOVED]/osa5.gif
    • [http://]www.thefunkiest.com/[REMOVED]/osa5.gif
    • [http://]www.jeoushinn.com/[REMOVED]/osa5.gif
    • [http://]www.presley.ch/[REMOVED]/osa5.gif
      
      Note: At the time of writing, the files were not available.
      
      
15. Attempts to save the downloaded file as %Windir%\_re_file.exe and then executed it.
    
    Note: It has been reported that the downloaded file may be a Beagle variant.
    
    
16. Creates the following registry subkey:
    
    HKEY_CURRENT_USER\Software\FirstRun\FirstRunRR
    
    which is used as an infection marker.
    
    
17. Opens notepad.exe.
    
    Note: This only occurs after the first time the Trojan is launched.

Recommendations

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

• Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
• Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
• Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
• Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
• Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
• Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
• If a threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
• Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate compromised computers quickly to prevent threats from spreading further. Perform a forensic analysis and restore the computers using trusted media.
• Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.
• If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
• For further information on the terms used in this document, please refer to the Security Response glossary.