W32.Looked.J

W32.Looked.J is a worm that spreads through network shares and attempts to infect .exe files. It also lowers security settings.


When the worm is executed, it creates the following files:
%Windir%\rundl132.exe - detected as W32.Looked.J
%CurrentFolder%\vDll.dll - detected as Downloader

The worm then checks for the presence of the following registry entry and exits if found:
HKEY_LOCAL_MACHINE\SOFTWARE\Soft\DownloadWWW\"auto" = "1"

If the above registry entry does not exist, the worm will create it as an infection marker.

The worm creates the following registry entry, to ensure it gets automatically executed at startup:
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows\"load" = "%Windir%\rundl132.exe"

The worm attempts to stop the following service:
Kingsoft AntiVirus Service

The worm then injects its DLL component, vDll.dll, into either iexplorer.exe or explorer.exe.

This DLL component will attempt to download a file from the following location:
www.17dk.com

The worm searches for .exe files to infect in all the drives from C to Y.

The worm prepends itself to any .exe files that it locates on the computer.

The worm creates the file _desktop.ini in any any directory it has searched for executable files in. This file has the hidden and system attributes set and it stores the date the worm was executed.

The worm will not infect .exe files in folders with the following names:
system
system32
windows
Documents and Settings
System Volume Information
Recycled
winnt
Program Files
Windows NT
WindowsUpdate
Windows Media Player
Outlook Express
Internet Explorer
ComPlus Applications
NetMeeting
Common Files
Messenger
Microsoft Office
InstallShield Installation Information
MSN
Microsoft Frontpage
Movie Maker
MSN Gaming Zone

The worm may send ICMP packets containing the string "Hello,World" to the following IP addresses:
192.168.0.30
192.168.8.1

It may also send ICMP packets to IP addresses in the same range as the IP address of the compromised computer.

If any computer responds to the ICMP packet, the worm attempts to open shared folders with the following names:
\\ipc$
\\admin$

The shared folder will have the username administrator and a blank password.

If the worm succeeds in opening the shared folder, it copies itself to that folder.

The worm then enumerates all the computers and shared folders in the local network. The worm uses a blank username and a blank password to open the shared folders.

The worm then searches for and infects .exe files in the shared folders.

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.

Summary