W32.Imaut.N

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Discovered: December 12, 2006
Updated: July 30, 2013 8:03:14 AM
Also Known As: IM-Worm.Win32.Sohanad.t [Kaspersky], W32/Sohana-R [Sophos]
Type: Worm
Systems Affected: Windows

W32.Imaut.N is a worm that spreads through Yahoo! Instant Messenger.

Antivirus Protection Dates

  • Initial Rapid Release version December 13, 2006
  • Latest Rapid Release version June 19, 2018 revision 033
  • Initial Daily Certified version December 13, 2006
  • Latest Daily Certified version June 20, 2018 revision 008
  • Initial Weekly Certified release date December 13, 2006

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

Writeup By: Maryl Magee

Discovered: December 12, 2006
Updated: July 30, 2013 8:03:14 AM
Also Known As: IM-Worm.Win32.Sohanad.t [Kaspersky], W32/Sohana-R [Sophos]
Type: Worm
Systems Affected: Windows

W32.Imaut.N is a worm that spreads through Yahoo! Instant Messenger.

Once executed, the worm downloads a file from the following location:
[http://]www.freewebs.com/nhattru[REMOVED]

The worm then saves the downloaded file as the following file:
%System%\RVHOST.exe

The worm creates the following file on shared drives:
%System%\new folder.exe

The worm then creates the following Windows job file with settings to execute RVHOST.exe at 9:00am every day:
%Windir%\Tasks\At1.job

The worm creates the following registry entries so that it runs every time Windows starts:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\"Shell" = "Explorer.exe " RVHOST.exe"
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\"Yahoo Messengger" = "%System%\RVHOST.exe"

The worm also creates the following registry entry:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\WorkgroupCrawler\Shares\"shared" = "[SHARED DRIVE]\New Folder.exe"

The worm then modifies the following registry entries to disable the Task Manager and the Registry Editor:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System\"DisableTaskMgr" = "1"
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System\"DisableRegistryTools" = "1"

The worm also modifies the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\"NofolderOptions" = "1"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Schedule\"AtTaskMaxHours" = "0"

The worm then deletes the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\"Run" = "BkavFw"
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\"Run" = "IEProtection"

The worm ends the following processes and closes applications if they are running:
Registry Editor
Task Manager
Bkav2006
game_y.exe
"System Configuration"

Next, the worm sends the following messages through Yahoo! Instant Messenger:
"E may, vao day coi co con nho nay ngon lam [http://]nhattruongquang.0catch.com

"Vao day nghe bai nay di ban [http://]nhattruongquang.0catch.com"

"Vao day nghe bai nay di ban [http://]nhattruongquang.0catch.com"

"Biet tin gi chua, vao day coi di [http://]nhattruongquang.0catch.com"

"Trang Web nay coi cung hay, vao coi thu di [http://]nhattruongquang.0catch.com"

"Toi di lang thang lan trong bong toi buot gia, ve dau khi da mat em roi? Ve dau khi bao nhieu mo mong gio da vo tan... Ve dau toi biet di ve dau? [http://]nhattruongquang.0catch.com"

"Khoc cho nho thuong voi trong long, khoc cho noi sau nhe nhu khong. Bao nhieu yeu thuong nhung ngay qua da tan theo khoi may bay that xa... [http://]nhattruongquang.0catch.com"

"Tha nguoi dung noi se yeu minh toi mai thoi thi gio day toi se vui hon. Gio nguoi lac loi buoc chan ve noi xa xoi, cay dang chi rieng minh toi... [http://]nhattruongquang.0catch.com"

"Loi em noi cho tinh chung ta, nhu doan cuoi trong cuon phim buon. Nguoi da den nhu la giac mo roi ra di cho anh bat ngo... [http://]nhattruongquang.0catch.com"

"Tra lai em niem vui khi duoc gan ben em, tra lai em loi yeu thuong em dem, tra lai em niem tin thang nam qua ta dap xay. Gio day chi la nhung ky niem buon...[http://]nhattruongquang.0catch.com"

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: Maryl Magee

Discovered: December 12, 2006
Updated: July 30, 2013 8:03:14 AM
Also Known As: IM-Worm.Win32.Sohanad.t [Kaspersky], W32/Sohana-R [Sophos]
Type: Worm
Systems Affected: Windows

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: Maryl Magee