1. Symantec/
  2. Security Response/
  3. Trojan.Virantix.C

Trojan.Virantix.C

Risk Level 1: Very Low

Discovered:
May 9, 2008
Updated:
May 9, 2008 6:28:10 PM
Also Known As:
Troj/Agent-HFD [Sophos], Troj/Spywad-AZ [Sophos]
Type:
Trojan
Infection Length:
71,168 bytes
Systems Affected:
Windows
When the Trojan is executed, it overwrites the beep.sys driver and drops the following files:
  • %System%\dllcache\figaro.sys
  • %System%\braviax.exe

It replaces the following files with the figaro.sys file:
  • %Windir%\drivers\beep.sys
  • %System%\dllcache\beep.sys
  • %System%\drivers\beep.sys

The Trojan then restarts the computer in order to activate the following files:
  • figaro.sys
  • braviax.exe


When the computer restarts, the Trojan displays the following warning message:





Title: Your computer is infected!

Message Body:
Windows has detected spyware infection!

It is recomended to use special antispyware tools to prevent data loss. Windows will now download and install the most up-to-date antispyware for you.

Click here to protect your computer from spyware!

The Trojan then drops the following files:
  • %CurrentFolder%\delself.bat
  • %System%\univrs32.dat

Next, the Trojan creates the following registry entry, so that it runs every time Windows starts:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\"braviax" = "%System%\braviax.exe"

The Trojan modifies the following registry entries to lower security settings:
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SecurityCenter\"AntiVirusDisableNotify" = "01000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SecurityCenter\"FirewallDisableNotify" = "01000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SecurityCenter\"UpdatesDisableNotify" = "01000000"
  • HKEY_CURRENT_USER\SOFTWARE\Microsoft\SecurityCenter\"AntiVirusDisableNotify" = "01000000"
  • HKEY_CURRENT_USER\SOFTWARE\Microsoft\SecurityCenter\"FirewallDisableNotify" = "01000000"
  • HKEY_CURRENT_USER\SOFTWARE\Microsoft\SecurityCenter\"UpdatesDisableNotify" = "01000000"
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\EnableFirewall" = "00000000"

It modifies the following registry entries to change Internet settings:
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\0\"1200" = "00000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\0\"1201" = "00000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\0\"1208" = "00000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\0\"1608" = "00000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\0\"1804" = "01000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\0\"2500" = "03000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\1\"1200" = "00000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\1\"1201" = "00000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\1\"1208" = "00000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\1\"1608" = "00000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\1\"1804" = "01000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\1\"2500" = "03000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\2\"1200" = "00000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\2\"1201" = "00000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\2\"1208" = "00000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\2\"1608" = "00000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\2\"1804" = "01000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\2\"2500" = "03000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\3\"1200" = "00000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\3\"1201" = "00000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\3\"1208" = "00000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\3\"1608" = "00000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\3\"1804" = "01000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\3\"2500" = "03000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\4\"1200" = "00000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\4\"1201" = "00000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\4\"1208" = "00000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\4\"1608" = "00000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\4\"1804" = "01000000"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\4\"2500" = "03000000"


It modifies the following registry entries:
  • HKEY_CURRENT_USER\Software\Microsoft\InternetExplorer\Main\"EnableBrowserExtensions" = "yes"
  • HKEY_CURRENT_USER\Software\Microsoft\InternetExplorer\Main\"SearchBar" = "http://www.google.com/ie"
  • HKEY_CURRENT_USER\Software\Microsoft\InternetExplorer\Main\"SearchPage" = "http://www.google.com"
  • HKEY_CURRENT_USER\Software\Microsoft\InternetExplorer\Main\"StartPage" = "http://www.google.com"
  • HKEY_LOCAL_MACHINE\Software\Microsoft\InternetExplorer\Main\"Default_Search_URL" = "http://www.google.com/ie"
  • HKEY_LOCAL_MACHINE\Software\Microsoft\InternetExplorer\Main\"SearchPage" = "http://www.google.com"
  • HKEY_LOCAL_MACHINE\Software\Microsoft\InternetExplorer\Main\"StartPage" = "http://www.google.com"
  • HKEY_LOCAL_MACHINE\Software\Microsoft\InternetExplorer\Search\"SearchAssistant" = "http://www.google.com"

The Trojan then contacts the following remote location and attempts to download and execute a misleading application:
[http://]www.softcashier.com/members/link[REMOVED]

At the time of writing, the application was WinReanimator.

The Trojan may then end the following processes:
  • aluschedulersvc.exe
  • appsvc32.exe
  • apvxdwin.exe
  • ashmaisv.exe
  • ashserv.exe
  • ashwebsv.exe
  • autoruns.exe
  • avciman.exe
  • avengine.exe
  • avgagent.exe
  • avgamsvr.exe
  • avgas.exe
  • avgas.exe
  • avgcc.exe
  • avgemc.exe
  • avgemc.exe
  • avgupsvc.exe
  • avgupsvc.exe
  • avgw.exe
  • avgw.exe
  • avp.exe
  • avpcc.exe
  • avpm.exe
  • avsched32.exe
  • avz.exe
  • bdmcon.exe
  • bdss.exe
  • bolenja.exe
  • bolenjx.exe
  • cavrid.exe
  • cavtray.exe
  • ccapp.exe
  • ccevtmgr.exe
  • ccevtmgr.exe
  • ccimscan.exe
  • ccproxy.exe
  • ccpwdsvc.exe
  • ccpwdsvc.exe
  • ccpxysvc.exe
  • ccsetmgr.exe
  • ccsetmgr.exe
  • ccsvchst.exe
  • combo.exe
  • combofix
  • comboxfix.exe
  • cpd.exe
  • cpf.exe
  • crypserv.exe
  • cureit.exe
  • defwatch.exe
  • dsentry.exe
  • dss.exe
  • eyetidecontroller.exe
  • farsighter.exe
  • fatbuster.exe
  • fsav32.exe
  • fsbl.exe
  • f-sched.exe
  • fsm32.exe
  • f-stopw.exe
  • fwservice.exe
  • gcasdtserv.exe
  • gcasserv.exe
  • globkill.exe
  • gmer.exe
  • hackmon.exe
  • hbtoeaddon.exe
  • hijackthis
  • hitvirus.exe
  • hwpe2.exe
  • iao.exe
  • icmon.exe
  • inetupd.exe
  • ismini.exe
  • isnotify.exe
  • issvc.exe
  • issvc.exe
  • kav.exe
  • kavss.exe
  • kavsvc.exe
  • killbox.exe
  • klpf.exe
  • klswd.exe
  • kmd.exe
  • kpf4ss.exe
  • little_helper2.exe
  • livesrv.exe
  • lsasrv.exe
  • lsass32.exe
  • lsetup.exe
  • lucoms~1.exe
  • magiclink.exe
  • malscr.exe
  • malswep.exe
  • mcshield.exe
  • msmpeng.exe
  • msssrv.exe
  • mwsoemon.exe
  • myvideodaily2.exe
  • navapp.exe
  • navapsvc.exe
  • navapsvc.exe
  • navapsvc.exe
  • navilog
  • navstub.exe
  • navw32.exe
  • nisum.exe
  • njexplor.exe
  • nlsupervisorpro.exe
  • no32mon.exe
  • nod32krn.exe
  • nod32ra.exe
  • nortonupdate.exe
  • nsmdtr.exe
  • nvctrl.exe
  • ofcdog.exe
  • op_mon.exe
  • outpost.exe
  • overseer.exe
  • overspy.exe
  • pavfnsvr.exe
  • pavfnsvr.exe
  • pavprsrv.exe
  • pavsrv51.exe
  • pbcpl.exe
  • pboptions.exe
  • pifsvc.exe
  • prevxcsi.exe
  • prevxcsi.exe
  • printer.exe
  • procmast.exe
  • psctrls.exe
  • pshost.exe
  • psimsvc.exe
  • pskmssvc.exe
  • rootkit_detektive.exe
  • rtvscan.exe
  • sandboxieserver.exe
  • savscan.exe
  • savscan.exe
  • sbserv.exe
  • sdfix.exe
  • sdtrayapp.exe
  • sndmon.exe
  • sndsrvc.exe
  • spbbcsvc.exe
  • spyblock.dll
  • spybot.exe
  • spybotsd.exe
  • spywaredetector.exe
  • superantispyware.exe
  • svcntaux.exe
  • svcntaux.exe
  • swdsvc.exe
  • swdsvc.exe
  • symlcsvc.exe
  • symlcsvc.exe
  • symwsc.exe
  • thguard.exe
  • tpsrv.exe
  • trjscan.exe
  • vundofix.exe
  • winavxx.exe
  • zclient.exe
  • zcodec.exe
  • zcomservice.exe


The Trojan also attempts to prevent the following drivers from loading:
  • bc_hassh_f.sys
  • bcfilter.sys
  • bcftdi.sys
  • vsdatant.sys
  • watchdog.sys

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.
Writeup By: Alfredo Pesoli
Summary| Technical Details| Removal

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