Threat Explorer

The Threat Explorer is a comprehensive resource consumers can turn to for daily, accurate, up-to-date information on the latest threats, risks and vulnerabilities.

VBS.Dunihi

VBS.Dunihi

Discovered:
September 12, 2013
Updated:
September 26, 2013
Infection Length:
15,795 bytes
Systems Affected:
Windows
VBS.Dunihi is a worm that spreads through removable media and may open a back door on the compromised computer, steal information, and download additional threats.

This worm was previously detected as the following:
Trojan.Malscript
VBS.Downloader.Trojan
Backdoor.Trojan
VBS.Runauto

Antivirus Protection Dates

  • Initial Rapid Release version September 12, 2013 revision 022
  • Latest Rapid Release version October 20, 2017 revision 004
  • Initial Daily Certified version September 12, 2013 revision 032
  • Latest Daily Certified version October 20, 2017 revision 006
  • Initial Weekly Certified release date September 18, 2013
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.
The worm spreads by copying itself to removable drives.

When the worm is executed, it copies itself to the following locations:
    • %UserProfile%\Application Data\[RANDOM CHARACTERS].vbs
    • %UserProfile% \Start Menu\Programs\Startup\[RANDOM CHARACTERS].vbs
    • %Temp%\[RANDOM CHARACTERS].vbs
    • [START UP]\[RANDOM CHARACTERS].vbs
    • [REMOVABLE DRIVE]\[RANDOM CHARACTERS].vbs
    • [REMOVABLE DRIVE]\[FOLDER NAME].lnk
    • [REMOVABLE DRIVE]\[FILE NAME].lnk

    Note:
    The worm creates .lnk files to replace every folder and file in removable media. The attributes of the original folders and files are set to "System" and "Hidden" to hide them from the user.

    The worm may drop the following files to the same folder the worm executable is located in:
    • s_h-plugin.bin
    • h_h-plugin.bin
    • p_h-plugin.bin

    The worm may create the following registry entries so that it runs every time Windows starts:
    • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\"[RANDOM CHARACTERS]" = "wscript.exe //B "%Temp%\[RANDOM CHARACTERS].vbs""
    • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\"[RANDOM CHARACTERS]" = "wscript.exe //B "%UserProfile%\Application Data\[RANDOM CHARACTERS].vbs""
    • HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run\"[RANDOM CHARACTERS]" = "wscript.exe //B "%Temp%\[RANDOM CHARACTERS].vbs""
    • HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run\"[RANDOM CHARACTERS]" = "wscript.exe //B "%UserProfile%\Application Data\[RANDOM CHARACTERS].vbs""

    The worm opens a back door and connects to the following domains:
    • school-pc.sytes.net:455
    • no99.zapto.org:81

    The worm may perform the following actions:
    • Accept and execute commands
    • Spread to USB or removable drives
    • Download and execute files
    • Update or uninstall itself
    • Log key strokes
    • Take screenshots
    • Terminate processes
    • Take screenshots
    • Upload a local file back to the attacker
    • Delete a local file

    The worm may also steal the following information from the compromised computer:
    • Drive list
    • File list
    • Folder list
    • Process list
    • Computer name
    • User name
    • Operating system version
    • Disk serial number
    • Installed antivirus products

    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.
    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.



    FOR NORTON USERS
    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 it using 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.


    FOR BUSINESS USERS
    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 it using 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



    MANUAL REMOVAL
    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: Nino Fred P Gutierrez & Masaki Suenaga