Downloader-BDU

Detection was added to cover protection against a malicious 32 bit downloader trojan originally called "html32.exe" , having a filesize of 32.768 bytes.  The file is written with MSVB6 and is not internally compressed with a packer.

Upon running, it displays a small messagebox titled "Your e-mail:Confirmed!" and content "Thank You!"

The Downloader has in between silently copied itself to the %windows% directory and made a registry entry to launch itself automatically upon system startup, for example on a Win2000 system:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run "Windows HTML"
  with Data: C:\WINNT\html32.exe (filesize 32.768 bytes)

It tries to access a specified website to download further files from:

• http://###.netf###s.com/up#.exe
• http://###.netf###s.com/sc#.exe

It also makes a log entry on:

• http://scu###.100web###e.net/cgi-bin/###/RAlog.cgi?action=log

The exact webaddresses are modified on purpose here with # markings.

It uses the port 1917.

• Presence of a malicious 32 bit downloader originally called "html32.exe" , having a filesize of 32.768 bytes.
• Seeing a small messagebox titled "Your e-mail:Confirmed!" and content "Thank You!"
• Unexpected traffic to:  http://###.netf###s.com/up#.exe 
• Unexpected traffic to:  http://###.netf###s.com/sc#.exe  
• Unexpected traffic to:  http://scu###.100web###e.net/cgi-bin/###/RAlog.cgi?action=log
• Unexpected use of port 1917

• Manual infection - there's no exploit associated with it

All Users:
Use current engine and DAT files for detection and removal.

Modifications made to the system Registry and/or INI files for the purposes of hooking system startup, will be successfully removed if cleaning with the recommended engine and DAT combination (or higher).

But in some particular cases, the following steps need to be taken.

Please go to the Microsoft Recovery Console and restore a clean MBR.

On Windows XP:

• Insert the Windows XP CD into the CD-ROM drive and restart the computer.
• When the "Welcome to Setup" screen appears, press R to start the Recovery Console.
• Select the Windows installation that is compromised and provide the administrator password.
• Issue 'fixmbr' command to restore the Master Boot Record
• Follow onscreen instructions.
• Reset and remove the CD from CD-ROM drive.

On Windows Vista and 7:

• Insert the Windows CD into the CD-ROM drive and restart the computer.
• Click on "Repair Your Computer".
• When the System Recovery Options dialog comes up, choose the Command Prompt.
• Issue 'bootrec /fixmbr' command to restore the Master Boot Record.
• Follow onscreen instructions.
• Reset and remove the CD from CD-ROM drive.