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Discovered: May 02, 2010
Updated: April 23, 2012 4:38:25 AM
Also Known As: Troj/PushBot-U [Sophos]
Type: Worm
Infection Length: Varies
Systems Affected: Windows

W32.Yimfoca is a worm that spreads by sending links through Yahoo! Messenger and displays surveys when popular websites are visited.

For more information, please see the following resources:
Blog entries on W32.Yimfoca

Antivirus Protection Dates

  • Initial Rapid Release version May 01, 2010 revision 034
  • Latest Rapid Release version September 12, 2019 revision 023
  • Initial Daily Certified version May 02, 2010 revision 005
  • Latest Daily Certified version August 04, 2019 revision 002
  • Initial Weekly Certified release date May 05, 2010

Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Technical Description

When executed, the worm copies itself as the following file:

It then attempts to copy the following file to the %Windir%, %UserProfile%\Public, or %ProgramFiles% folder, whichever it successfully copies to first:
[FOLDER NAME]\nvsvc32.exe

It also creates the following files:

  • %Windir%\mds.sys
  • %Windir%\mdt.sys
  • %Windir%\mdl.dl
  • %Windir%\winbrd.jpg
  • %Windir%\winbrd.png
  • %Windir%\winbrfy.jpg

It then creates the following registry entry so that it runs every time Windows starts:
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\"Firewall Administrating" = "%Windir%\infocard.exe"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\NVIDIA driver monitor: "[FOLDER NAME]\nvsvc32.exe"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\NVIDIA driver monitor: "[FOLDER NAME]\nvsvc32.exe"

The worm will also create the following registry entries in order to bypass the Windows Firewall:
  • HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List\"[FOLDER NAME]\nvsvc32.exe" = "[FOLDER NAME]\nvsvc32.exe:*:Enabled:NVIDIA driver monitor"
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List\"[FOLDER NAME]\nvsvc32.exe" = "[FOLDER NAME]\nvsvc32.exe:*:Enabled:NVIDIA driver monitor"

It also modifies the following registry entry, changing the Internet Explorer home page:
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\"Start Page" = "http://redirecturls.info"

Note: The worm will reset the home page to this URL every 30 minutes.

Next, the worm attempts to connect to the following URL:

The worm then stops the following processes to disable the Microsoft Malware Protection Service and Windows Update:
  • MsMpSvc
  • wuauserv

It then attempts to connect to the following URL to download a configuration file:

The worm may also download other files on to the compromised computer, which may be copies of other malware.

It connects to the following network addresses on TCP port 2345 and waits for IRC commands:
  • e2doo.org
  • sls.e2doo.net

It may also connect to one of the following URLs:
  • [http://]screenservice.com/inde[REMOVED]
  • [http://]jb.asm.org/inde[REMOVED]
  • [http://]scribbidyscrubs.com/inde[REMOVED]
  • [http://]tripadvisor.com/inde[REMOVED]
  • [http://]journals.lww.com/inde[REMOVED]
  • [http://]erdbeerlounge.de/inde[REMOVED]
  • [http://]heidegger.x-y.net/inde[REMOVED]
  • [http://]middleastpost.org/inde[REMOVED]
  • [http://]mcsp.lvengine.com/inde[REMOVED]
  • [http://]versatek.com/inde[REMOVED]
  • [http://]astro.ic.ac.uk/inde[REMOVED]
  • [http://]goodreads.com/inde[REMOVED]
  • [http://]albertoshistory.info/inde[REMOVED]
  • [http://]stayontime.info/inde[REMOVED]
  • [http://]websitetrafficspy.com/inde[REMOVED]
  • [http://]southampton.ac.uk/inde[REMOVED]
  • [http://]refugee-action.org.uk/inde[REMOVED]
  • [http://]unclefed.com/inde[REMOVED]
  • [http://]transnationale.org/inde[REMOVED]
  • [http://]journalofaccountancy.com/inde[REMOVED]
  • [http://]summer-uni-sw.eesp.ch/inde[REMOVED]
  • [http://]www.shearman.com/inde[REMOVED]
  • [http://]shopstyle.com/inde[REMOVED]
  • [http://]deirdremccloskey.org/inde[REMOVED]
  • [http://]hrm.uh.edu/inde[REMOVED]
  • [http://]insidehighered.com/inde[REMOVED]
  • [http://]mix.thenaturistclub.com/inde[REMOVED]
  • [http://]ate.lacoctelera.net/inde[REMOVED]
  • [http://]xxx.stopklatka.pl/inde[REMOVED]
  • [http://]mas.univie.ac.at/inde[REMOVED]
  • [http://]opl.munin.irf.se/inde[REMOVED]
  • [http://]mas.0730ip.com/inde[REMOVED]
  • [http://]mas.ahlamontada.com/inde[REMOVED]
  • [http://]xxx.jagdcom.de/inde[REMOVED]
  • [http://]old.longjuyt2tugas.com/inde[REMOVED]
  • [http://]mmm.bolbalatrust.org/inde[REMOVED]
  • [http://]mix.price-erotske.in.rs/inde[REMOVED]
  • [http://]mas.juegosbakugan.net/inde[REMOVED]
  • [http://]qun.51.com/inde[REMOVED]
  • [http://]epp.gunmablog.jp/inde[REMOVED]
  • [http://]old.youku.com/inde[REMOVED]
  • [http://]mas.tguia.cl/inde[REMOVED]
  • [http://]ope.oaklandathletics.com/inde[REMOVED]
  • [http://]beta.neogen.ro/inde[REMOVED]
  • [http://]ale.pakibili.com/inde[REMOVED]
  • [http://]mas.mtime.com/inde[REMOVED]
  • [http://]pru.landmines.org/inde[REMOVED]
  • [http://]uks.linkedin.com/inde[REMOVED]
  • [http://]mas.josbank.com/inde[REMOVED]
  • [http://]mas.archivum.info/inde[REMOVED]
  • [http://]ols.systemofadown.com/inde[REMOVED]
  • [http://]pra.aps.org/inde[REMOVED]

Next, the worm searches windows on the compromised computer for those that belong to Yahoo! Messenger.

The worm spreads by sending messages that contain links to copies of the worm to all Yahoo! Messenger contacts.

The following messages may be sent by the worm:
  • foto :D [http://]tusfbfotos.com/imag[REMOVED]
  • foto :D [http://]kompnk.com/imag[REMOVED]
  • foto :D [http://]beautyphotoson.com/imag[REMOVED]

The worm will prompt users to fill out surveys in order to gain access to popular sites such as facebook.com, if they are using Internet Explorer. The user will be unable to log into his or her account until a survey is completed. Survey messages include the following:
  • You have only 3 minutes to fill out the selected survey or you will be banned from this site.
  • Complete one of these surveys to gain access this page. Otherwise you will not have access to this page.

If the following strings are typed into the Internet Explorer address bar, further surveys may be displayed or the browser will be closed:
  • vagina
  • bick
  • fuck
  • XXX
  • virus
  • hardcore
  • drug
  • sexua
  • porn
  • register
  • r.php
  • login
  • cpa
  • facebook
  • cpa
  • lead
  • google
  • bing
  • yahoo
  • live
  • mail
  • microsoft
  • window
  • aricles
  • vidr
  • ruch
  • porn
  • sex
  • tube
  • adult
  • gllo
  • xnxx
  • xvideos
  • kyarticl
  • lmsarchiv
  • rticleslo
  • fuck
  • afemo
  • fullarti
  • i24searc
  • article
  • kanaa
  • enthou
  • iggarti
  • virus
  • myspace
  • postart
  • perbizsear
  • m-new
  • cpalead
  • freeart
  • astmo
  • cpa
  • lead
  • outu
  • daddie
  • porn
  • gay
  • adobe
  • geshac


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.


You may have arrived at this page either because you have been alerted by your Symantec product about this risk, or you are concerned that your computer has been affected by this risk.

Before proceeding further we recommend that you run a full system scan . If that does not resolve the problem you can try one of the options available below.

If you are a Norton product user, we recommend you try the following resources to remove this risk.

Removal Tool

If you have an infected Windows system file, you may need to replace them using from the Windows installation CD .

How to reduce the risk of infection
The following resources provide further information and best practices to help reduce the risk of infection.

If you are a Symantec business product user, we recommend you try the following resources to remove this risk.

Identifying and submitting suspect files
Submitting suspicious files to Symantec allows us to ensure that our protection capabilities keep up with the ever-changing threat landscape. Submitted files are analyzed by Symantec Security Response and, where necessary, updated definitions are immediately distributed through LiveUpdate™ to all Symantec end points. This ensures that other computers nearby are protected from attack. The following resources may help in identifying suspicious files for submission to Symantec.

Removal Tool

If you have an infected Windows system file, you may need to replace them using from the Windows installation CD .

How to reduce the risk of infection
The following resource provides further information and best practices to help reduce the risk of infection.
Protecting your business network

The following instructions pertain to all current Symantec antivirus products.

1. Performing a full system scan
How to run a full system scan using your Symantec product

2. Restoring settings in the registry
Many risks make modifications to the registry, which could impact the functionality or performance of the compromised computer. While many of these modifications can be restored through various Windows components, it may be necessary to edit the registry. See in the Technical Details of this writeup for information about which registry keys were created or modified. Delete registry subkeys and entries created by the risk and return all modified registry entries to their previous values.

Writeup By: Mircea Ciubotariu