Trojan-Dropper:W32/VB.ME

Summary

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Trojan-Dropper.Win32.VB.me drops multiple copies of itself to saved download folders of known Peer-to-Peer applications.

Removal

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Automatic action

Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.

More

Detailed instructions for F-Secure security products are available in the documentation found in the Downloads section of our Home - Global site.

You may also refer to the Knowledge Base on the F-Secure Community site for further assistance.

Technical Details

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The malware's behavior primarily involves the use of peer-to-peer (P2P) applications. It initially checks for the existence of the following P2P configuration files and registry configuration to get the Directory where the downloaded files were kept:

• %appdata%\LimeWire\.limewire.props
• %appdata%\morpheus\morphconfig.ini
• %appdata%\morpheus ultra\morphconfig.ini
• %programfiles%\BearShare\FreePeers.ini

It then queries the following P2P application executables and executes them if they exist:

• %programfiles%\limewire\limewire.exe
• %programfiles%\shareaza\shareaza.exe
• %programfiles%\bearshare\bearshare.exe
• %programfiles%\morpheus\morpheus.exe
• %programfiles%\morpheus ultra\morpheus.exe

By design, it will initially just check for a LimeWire installation. Checking for BearShare, Morpheus, Morpheus Ultra, and Shareaza will be done after checking if any of the following executables: bearshare.exe, morpheus.exe, or shareaza.exe are running in the processes. It then adds a hidden "_" folder in location where the default Saved folder is located. To continue, it first checks if it is running as %alluserstartup%\wmplayer.exe. If no, it generates a message box then exits:

• "Windows Media Player" "Media player cannot play file codec is missing"

If yes, it check to see if any of the following files exist in the system directory:

• winlog.exe
• p2pnetworking.exe
• scvhost.exe
• winlogi.exe
• p2pnetwork.exe
• csrrs.exe

If the files are not found it drops and execute %windows%\b.exe. It locks the following system tools to prevent easy removal of the malware:

• %system%\cmd.exe
• %system%\netstat.exe
• %system%\tracert.exe
• %system%\ping.exe
• %system%\ipconfig.exe
• %system%\taskkill.exe
• %system%\regedt32.exe
• %system%\taskmgr.exe
• %windows%\regedit.exe

Attempt to execute the said tools prompts a message box:

• [appname] "Another program is currently using this file"

It then drops a copy of itself as "yesyesyesyes.exe" to the saved directory of the target psp app inside the created "_" folder. It downloads the page:

• http://www.mp3000.net[REMOVED]ads/page[randomdigit]-mp3.php

It parses through file to get music or video titles, usually containing the most recent ones. Using these names it then creates a copy of itself on the saved download folders.