TROJ_RANKY.AA

Malware type: Trojan

Aliases: Backdoor.Win32.IRCBot.bl (Kaspersky), W32/Sdbot.worm.gen (McAfee), Trojan.Dropper (Symantec), Worm/SdBot.111602 (Avira), Troj/Mdrop-N (Sophos), TrojanDropper:Win32/Small (Microsoft)

In the wild: No

Destructive: No

Language: English

Platform: Windows 95, 98, ME, NT, 2000, XP

Encrypted: No

Overall risk rating:

Reported infections:

Damage potential:

Medium

Distribution potential:

Low

Description: 

This Trojan drops and executes several malicious files that are detected by Trend Micro as the following:

It runs on Windows 95, 98, ME, NT, 2000, and XP.

For additional information about this threat, see:

Description created: Dec. 23, 2004 11:52:55 PM GMT -0800


TECHNICAL DETAILS


Size of malware: Varies

Initial samples received on: Dec 17, 2004

Related toWORM_SDBOT.TE, TROJ_RANKY.H, BKDR_SDBOT.GEN, TROJ_RANKY.AD

Details:

Upon execution, this Trojan drops and executes several malicious files that are detected by Trend Micro as the following:

  • C:\WINNT\system2\bbsdf.exe - TROJ_RANKY.AD
  • C:\WINNT\system2\dwdwqs.exe - BKDR_SDBOT.GEN
  • C:\WINNT\system2\dxxatp.exe - TROJ_RANKY.H
  • C:\WINNT\system2\qefbbs.exe - WORM_SDBOT.TE
  • %System%\fddwqt.exe - WORM_SDBOT.TE
  • %System%\ffbaqe.exe - WORM_SDBOT.TE

When the dropped files are executed, they create the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
msjdqs = "fddwqt.exe"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\RunServices
msjdqs = "fddwqt.exe"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
MSN Messenger BETA 7 = "C:\WINNT\SYSTEM32\bbsdf.exe"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
fddddHOME = "c:\winnt\system32\dxxatp.exe"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
msjdqs = "fddwqt.exe"

The dropped files connect to a remote IRC (Internet Relay Chat) server where it receives commands from a remote malicious user. The commands are then performed on an affected system thus compromising its security.




Analysis by: Daniel M. Biado


SOLUTION


Minimum scan engine version needed: 7.000

Pattern file needed: 2.250.12

Pattern release date: Dec 17, 2004


Important note: The "Minimum scan engine" refers to the earliest Trend Micro scan engine version guaranteed to detect this threat. However, Trend Micro strongly recommends that you update to the latest version in order to get comprehensive protection. Download the latest scan engine here.

Solution:

Note: Refer to the Clean Solution of the following malware to fully remove this Trojan from your system:

Restarting in Safe Mode

� On Windows 95

  1. Restart your computer.
  2. Press F8 at the Starting Windows 95 message.
  3. Choose Safe Mode from the Windows 95 Startup Menu then press Enter.

� On Windows 98 and ME

  1. Restart your computer.
  2. Press the CTRL key until the startup menu appears.
  3. Choose the Safe Mode option then press Enter.

� On Windows NT (VGA mode)

  1. Click Start>Settings>Control Panel.
  2. Double-click the System icon.
  3. Click the Startup/Shutdown tab.
  4. Set the Show List field to 10 seconds and click OK to save this change.
  5. Shut down and restart your computer.
  6. Select VGA mode from the startup menu.

� On Windows 2000

  1. Restart your computer.
  2. Press the F8 key, when you see the Starting Windows bar at the bottom of the screen.
  3. Choose the Safe Mode option from the Windows Advanced Options Menu then press Enter.

� On Windows XP

  1. Restart your computer.
  2. Press F8 after the Power-On Self Test (POST) is done. If the Windows Advanced Options Menu does not appear, try restarting and then pressing F8 several times after the POST screen.
  3. Choose the Safe Mode option from the Windows Advanced Options Menu then press Enter.

Note: After performing all the solutions for the removal of this malware, please restart your system normally, and run your Trend Micro antivirus product.

Removing Autostart Entries from the Registry

Removing autostart entries from the registry prevents the malware from executing at startup.

  1. Open Registry Editor. Click Start>Run, type REGEDIT, then press Enter.
  2. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>Software>Microsoft>
    Windows>CurrentVersion>Run
  3. In the right panel, locate and delete the entry:
    � MSN Messenger BETA 7 = "C:\WINNT\SYSTEM32\bbsdf.exe"
    � fddddHOME = "c:\winnt\system32\dxxatp.exe"
    � msjdqs = "fddwqt.exe"
  4. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>Software>Microsoft>
    Windows>CurrentVersion>Runservices
  5. In the right panel, locate and delete the entry:
    fddddHOME = "c:\winnt\system32\dxxatp.exe"
  6. In the left panel, double-click the following:
    HKEY_CURRENT_USER>Software>Microsoft>
    Windows>CurrentVersion>Run
  7. In the right panel, locate and delete the entry:
    msjdqs = "fddwqt.exe"
  8. Close Registry Editor.

NOTE: If you were not able to terminate the malware process as described in the previous procedure, restart your system.

Additional Windows ME/XP Cleaning Instructions

Users running Windows ME and XP must disable System Restore to allow full scanning of infected systems.

Users running other Windows versions can proceed with the succeeding procedure sets.

Running Trend Micro Antivirus

Scan your system with Trend Micro antivirus and delete all files detected as TROJ_RANKY.AA. To do this, Trend Micro customers must download the latest pattern file and scan their system. Other Internet users can use HouseCall, Trend Micro�s free online virus scanner.


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