Threat Description

Backdoor:​W32/SubSeven

Details

Aliases: SubSeven, Backdoor.SubSeven
Category: Malware
Type: Backdoor
Platform: W32

Summary



A remote administration utility that bypasses normal security mechanisms to secretly control a program, computer or network.



Removal



Automatic Disinfection

Allow F-Secure Anti-Virus to disinfect the relevant files.

For more general information on disinfection, please see Removal Instructions.



Technical Details



Backdoor:W32/SubSeven is a backdoor program that allows a remote user to perform a large range of actions on the affected system.

The first samples of this backdoor were not packed, but later some packed versions appeared which were not easy to detect with contemporary anti-virus programs that had no Win32 'Aspack' file compressor unpacking support.

SubSeven backdoor was first discovered in May, 1999. The backdoor is usually distributed under different names via newsgroups and e-mails.

Execution

When run, the backdoor copies itself to the Windows directory with the original name of the file it was run from or as SERVER.EXE, KERNEL16.DL, RUNDLL16.COM, SYSTEMTRAYICON!.EXE or WINDOW.EXE (names are different in different versions of SubSeven).

Then it unpacks a single DLL file to the Windows System directory - WATCHING.DLL (some versions don't do this). After that the backdoor patches Windows Registry so that its main application will be run during every Windows bootup (Run or RunServices keys). Finally, it creates and modifies some other Registry keys. The backdoor can also install itself to the system by modifying either the WIN.INI or the SYSTEM.INI file.

The latest versions of the SubSeven backdoor drop a small starter program (usually WINDOS.EXE) and register it to be run when any EXE file is started in Windows. By doing this the backdoor ensures that its copy is always in the memory. For specific instructions of how to disinfect these versions please see the bottom of the page.

All the recent versions of SubSeven are supplied with a server configuration utility that allows it to customize server part capabilities - installation method, custom startup message, etc. This method was first introduced by the Back Orifice 2000 backdoor and it allows much more flexibility to backdoors.

Activity

If the SubSeven backdoor task is being active in the memory (and invisible in Task Manager), it looks for TCP/IP connections and if they are established it listens to TCP/IP ports for commands from a client part.

Subseven also tries to use ICQ, IRC and different e-mail accounts to notify the author that his victims are online.

SubSeven's initial version had the following 113 capabilities:

  • Fun Manager ------------------
    • 1. Open Web Browser to specified location.
    • 2. Restart Windows.
    • 3. Reverse Mouse buttons.
    • 4. Hide Mouse Pointer.
    • 5. Move Mouse.
    • 6. Mouse Trail Config.
    • 7. Set Volume.
    • 8. Record Sound file from remote mic.
    • 9. Change Windows Colors / Restore.
    • 10. Hung up Internet Connection.
    • 11. Change Time.
    • 12. Change Date.
    • 13. Change Screen resolution.
    • 14. Hide Desktop Icons / Show
    • 15. Hide Start Button / Show
    • 16. Hide taskbar / Show
    • 17. Opne CD-ROM Drive / Close
    • 18. Beep computer Speaker / Stop
    • 19. Turn Monitor Off / On
    • 20. Disable CTRL+ALT+DEL / Enable
    • 21. Turn on Scroll Lock / Off
    • 22. Turn on Caps Locl / Off
    • 23. Turn on Num Lock / Off
  • Connection Manager -----------------------------
    • 1. Connect / Disconnect
    • 2. IP Scanner
    • 3. IP Address book
    • 4. Get Computer Name
    • 5. Get User Name
    • 6. Get Windows and System Folder Names
    • 7. Get Computer Company
    • 8. Get Windows Version
    • 9. Get Windows Platform
    • 10. Get Current Resolution
    • 11. Get DirectX Version
    • 12. Get Current Bytes per Pixel settings
    • 13. Get CPU Vendor
    • 14. Get CPU Speed
    • 15. Get Hard Drive Size
    • 16. Get Hard Drive Free Space
    • 17. Change Server Port
    • 18. Set Server Password
    • 19. Update Server
    • 20. Close Server
    • 21. Remove Server
    • 22. ICQ Pager Connection Notify
    • 23. IRC Connection Notify
    • 24. E-Mail Connection Notify
  • Keyboard Manager --------------------------
    • 1. Enable Key Logger / Disable
    • 2. Open Key Logger in a remote Window
    • 3. Clear the Key Logger Windows
    • 4. Collect Keys pressed while Offline
    • 5. Open Chat Victim + Controller
    • 6. Open Chat among all connected
  • Controllers --------------
    • 1. Windows Pop-up Message Manager
    • 2. Disable Keyboard
    • 3. Send Keys to a remote Window
  • Misc. Manager --------------------
    • 1. Full Screen Capture
    • 2. Continues Thumbnail Capture
    • 3. Flip Screen
    • 4. Open FTP Server
    • 5. Find Files
    • 6. Capture from Computer Camera
    • 7. List Recorded Passwords
    • 8. List Cached Passwords
    • 9. Clear Password List
    • 10. Registry Editor
    • 11. Send Text ot Printer
  • File Manager ------------------
    • 1. Show files/folders and navigate
    • 2. List Drives
    • 3. Execute Application
    • 4. Enter Manual Command
    • 5. Type path Manually
    • 6. Download files
    • 7. Upload files
    • 8. Get File Size
    • 9. Delete File
    • 10. Play *.WAV
    • 11. Set Wallpaper
    • 12. Print *.TXT\*.RTF file
    • 13. Show Image
  • Window Manager ------------------------
    • 1. List visible windows
    • 2. List All Active Applications
    • 3. Focus on Window
    • 4. Close Window
    • 5. Disable X (close) button
    • 6. Hide a Window from view.
    • 7. Show a Hidden Window
    • 8. Disable Window
    • 9. Enable Disabled Window
  • Options Menu --------------------
    • 1. Set Quality of Full Screen Capture
    • 2. Set Quality of Thumbnail Capture
    • 3. Set Chat font size and Colors
    • 4. Set Client's User Name
    • 5. Set local 'Download' Directory
    • 6. Set Quick Help
    • 7. Set Client Skin
    • 8. Set Fun Manager Skin
  • Edit Server --------------
    • 1. PreSet Target Port
    • 2. PreSet server Password
    • 3. Attach EXE File
    • 4. PreSet filename after installation
    • 5. PreSet Registry Key
    • 6. PreSet Autostart Method:
    • Registry: Run
    • Registry: RunSevices
  • Win.ini Less known method
    • 7. PreSet Fake error message
    • 8. PreSet Connection Notify Username
    • 9. PreSet Connection Notify ICQ#
    • 10. PreSet Connection Notify E-Mail
    • 11. PreSet Connection Notify IRC Chan.
    • 12. PreSet IRC Port
    • 13. Change Server *.exe Icon





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