1. Symantec/
  2. Security Response/
  3. W32.Wergimog.B


Risk Level 1: Very Low

May 16, 2012
May 18, 2012 1:55:57 AM
Infection Length:
94,208 bytes
Systems Affected:
When the worm is executed, it copies itself as one of the following file:
%UserProfile%/Application Data/Microsoft/services[THREE RANDOM NUMBERS].exe

Next, the worm may create the following registry entries, so that it executes whenever Windows starts:
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\"Adobe Reader Speed Launcher" = "%UserProfile%/Application Data/Microsoft/services[THREE RANDOM NUMBERS].exe"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\"Adobe Reader Speed Launcher" = "%UserProfile%/Application Data/Microsoft/services[THREE RANDOM NUMBERS].exe"

Next, it creates the following mutexes so that only one instance of the threat executes on the computer:
  • skkd)*u32hqiajnzja
  • (asdj2j3e)*oqwjkz

It starts the Explorer.exe process and injects its code into it. It may also inject itself into other processes as well. It won't inject itself into the following system related processes:
  • System
  • System Idle Process
  • csrss.exe

It then attempts to open a back door by connecting to the following remote locations on port 5786:
  • ns2.kasprsky.org
  • ns2.lksadxniuszkla.org

It may then perform the following actions:
  • Download and execute a remote file
  • Perform UDP and SYN flood attacks
  • Perform Slowloris attacks
  • List the directory
  • Execute process
  • Update and/or delete itself
  • Open a requested URL

It also attempts to steal the following information:
  • OS version
  • User account type
  • User name
  • FileZilla account details

It also attempts to steal user name and password information for the following websites:
  • paypal.com
  • hackforums.net
  • thepiratebay.org
  • megaupload.com
  • hotfile.com
  • fileserve.com
  • uploading.com

The worm attempts to hook DNS requests made to the following locations and modify it with www.google.com:
  • sophos.fr
  • sophos.com
  • housecall.com
  • jotti.org
  • novirusthanks.org
  • threatexpert.com
  • virus.org
  • virustotal.com
  • banners.fastclick.net
  • banner.fastclick.net
  • awaps.net
  • avp.com
  • avp.ch
  • atdmt.com
  • ar.atwola.com
  • ads.fastclick.net
  • ad.fastclick.net
  • ad.doubleclick.net
  • updates.symantec.com
  • service1.symantec.com
  • securityresponse.symantec.com
  • liveupdate.symantecliveupdate.com
  • liveupdate.symantec.com
  • customer.symantec.com
  • symantec.com
  • viruslist.ru
  • viruslist.com
  • f-secure.com
  • gdata.de
  • hijackthis.de
  • kaspersky-labs.com
  • kaspersky.com
  • kaspersky.ru
  • anti-virus.by

It also modifies any posts made on the following social networking sites:
  • Facebook
  • Twitter
  • Myspace
  • Linkedin
  • Hi5
  • Hyves
  • Omegle

Next, it searches for other malware on the compromised computer and ends any malware processes it finds.

The worm spreads by copying itself to removable drives as the following file:

It may also create the following file in order to execute whenever the 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: Takashi Katsuki
Summary| Technical Details| Removal

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