1. Symantec/
  2. Security Response/
  3. W32.Wapomi.D


Risk Level 2: Low

December 5, 2012
March 8, 2013 11:03:11 AM
Infection Length:
Systems Affected:
When the worm executes, it drops the following file, which is used to hide the presence of the worm:
%SystemDrive%\[RANDOM CHARACTERS].sys (Hacktool.Rootkit)

Next, it registers the above file as a service with the following characteristics:
Image Path: %SystemDrive%\[RANDOM CHARACTERS].sys
Startup: Automatic

It creates the following registry subkey in order to register the above service:

The worm then creates registry entries under the following registry subkey in order to disable certain antivirus applications:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options

It attempts to prevent the following antivirus-related files from executing:
  • 360hotfix.exe
  • 360rp.exe
  • 360rpt.exe
  • 360safe.exe
  • 360safebox.exe
  • 360sd.exe
  • 360se.exe
  • 360SoftMgrSvc.exe
  • 360speedld.exe
  • 360tray.exe
  • afwServ.exe
  • ast.exe
  • AvastUI.exe
  • avcenter.exe
  • avfwsvc.exe
  • avgnt.exe
  • avguard.exe
  • avmailc.exe
  • avp.exe
  • avshadow.exe
  • avwebgrd.exe
  • bdagent.exe
  • CCenter.exe
  • ccSvcHst.exe
  • dwengine.exe
  • egui.exe
  • ekrn.exe
  • FilMsg.exe
  • kavstart.exe
  • kissvc.exe
  • kmailmon.exe
  • kpfw32.exe
  • kpfwsvc.exe
  • krnl360svc.exe
  • ksmgui.e
  • ksmsvc.exe
  • kswebshield.exe
  • KVMonXP.kxp
  • KVSrvXP.exe
  • kwatch.exe
  • livesrv.exe
  • Mcagent.exe
  • mcmscsvc.exe
  • McNASvc.exe
  • Mcods.exe
  • McProxy.exe
  • McSACore.exe
  • Mcshield.exe
  • mcsysmon.exe
  • mcvsshld.exe
  • MpfSrv.exe
  • MPMon.exe
  • MPSVC.exe
  • MPSVC1.exe
  • MPSVC2.exe
  • msksrver.exe
  • qutmserv.exe
  • RavMonD.exe
  • RavTask.exe
  • RsAgent.exe
  • rsnetsvr.exe
  • RsTray.exe
  • safeboxTray.exe
  • ScanFrm.exe
  • sched.exe
  • seccenter.exe
  • SfCtlCom.exe
  • spideragent.exe
  • SpIDerMl.exe
  • spidernt.exe
  • spiderui.exe
  • TMBMSRV.exe
  • TmProxy.exe
  • Twister.exe
  • UfSeAgnt.exe
  • vsserv.exe
  • zhudongfangyu.exe

It then deletes registry entries under the following subkey in order to prevent the computer from restarting in Safe Mode:

The worm also modifies the following registry entries:
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\AppMgmt\"Start" = "3"
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\SW\{eec12db6-ad9c-4168-8658-b03daef417fe}\{ABD61E00-9350-47e2-A632-4438B90C6641}\"Service" = "drmkaud"

Next, the worm checks the status of the following services:
  • AppMgmt (appmgmts.dll)
  • BITS (qmgr.dll)
  • Browser (browser.dll)
  • CryptSvc (cryptsvc.dll)
  • EventSystem (es.dll)
  • FastUserSwitchingCompatibility (shsvcs.dll)
  • helpsvc (pchsvc.dll)
  • Netman (netman.dll)
  • Nla (mswsock.dll)
  • Ntmssvc (ntmssvc.dll)
  • RemoteRegistry (regsvc.dll)
  • Schedule (schedsvc.dll)
  • SSDPSRV (ssdpsrv.dll)
  • Tapisrv (tapisrv.dll)
  • upnphost (upnphost.dll)
  • WmdmPmSN (mspmsnsv.dll)
  • xmlprov (xmlprov.dll)

When the worm identifies that one of the above services is not running, it overwrites the the corresponding .dll file with a copy of itself and starts the infected service.

It then modifies the hosts file.

Next, the worm attempts to infect all .exe files by appending malicious code to the executable. It also tries to infect executable files within .rar files stored on shared network resources.

The worm does not infect any .exe files in folders that contain the following strings:
  • Common Files
  • ComPlus Applications
  • Documents and Settings
  • InstallShield Installation Information
  • Internet Explorer
  • Messenger
  • microsoft frontpage
  • Movie Maker
  • MSN Gaming Zone
  • NetMeeting
  • Outlook Express
  • System Volume Information
  • Thunder
  • Thunder Network
  • Windows Media Player
  • Windows NT
  • WindowsUpdate
  • WinNT
  • WinRAR

The worm also attempts to infect the following file types:
  • .asp
  • .aspx
  • .htm
  • .html

Next, the worm copies itself to removable drives as the following file:

It also creates the following file so that the worm executes whenever a removable drive is used on another computer:


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: Paul Mangan
Summary| Technical Details| Removal

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