WORM_ALCAN.A

Malware type: Worm

Aliases: W32/Sdbot.worm.gen.h (McAfee), W32.Spybot.Worm (Symantec), Worm/Alcan.A.2 (Avira), Backdoor:Win32/Rbot (Microsoft)

In the wild: Yes

Destructive: Yes

Language: English

Platform: Windows 98, 2000, XP

Encrypted: No

Overall risk rating:

Reported infections:

Damage potential:

High

Distribution potential:

High

Description: 

When executed, this worm shows the following error message:

Setup cannot continue on windows NT based systems , Click ok to end Setup

It drops copies of itself in the Windows system, Program files, and root folders.

This worm propagates via peer-to-peer networks by dropping a copy of itself in certain folders.

It also drops COM files that disables the execution of certain Windows tool applications.

For additional information about this threat, see:

Description created: May. 12, 2005 8:18:29 PM GMT -0800


TECHNICAL DETAILS


File type: PE

Memory resident:  Yes

Size of malware: 423,693 Bytes

Initial samples received on: May 12, 2005

Compression type: Petite

Details:

When executed, this worm shows the following error message:

Setup cannot continue on windows NT based systems , Click ok to end Setup

It drops a copy of itself in the following locations:

  • %Program files%\MsConfigs\MSCONFIGS.EXE
  • %System%\P2PNETWORK.EXE
  • C:\TEMP.ZIP

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files. %System% is the Windows system folder, which is usually C:\Windows\System on Windows 95, 98, and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP.)

It then creates the following autostart entries to ensure its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
p2pnetwork = "p2pnetwork.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunServices
p2pnetwork = "p2pnetwork.exe"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\RunServices
p2pnetwork = "p2pnetwork.exe"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
MsConfigs = "%Program files%\MsConfigs\MsConfigs.exe"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
p2pnetwork = "p2pnetwork.exe"

It also creates the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\System\CurrentControlSet\
Control\Lsa
p2pnetwork = "p2pnetwork.exe"

HKEY_CURRENT_USER\Software\Microsoft\
OLE
p2pnetwork = "p2pnetwork.exe"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Ole
p2pnetwork = "p2pnetwork.exe"

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Control\Lsa
p2pnetwork = "p2pnetwork.exe"

It also modifies the following registry entries:

FROM

HKEY_LOCAL_MACHINE\Software\Microsoft\
Ole
EnableDCOM = "Y"

TO

HKEY_LOCAL_MACHINE\Software\Microsoft\
Ole
EnableDCOM = "N"

FROM

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Control\Lsa
Restrictanonymous = �0x00000000�

TO

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Control\Lsa
Restrictanonymous = �0x00000001�

It propagates by attempting to drop a copy of itself in the following folders:

  • Ares\My Shared Folder
  • Bearshare\Shared
  • Edonkey2000\Incoming
  • eMule\Incoming
  • gnucleus\downloads
  • grokster\my grokster
  • Kazaa\My Shared Folder
  • Limewire\Shared
  • morpheus\My Shared Folder
  • rapigator\share
  • shareaza\downloads
  • shared
  • My Shared Folder

This worm drops the legitimate file compression DLL, BSZIP.DLL in the Windows system folder. It does this so it can compress itself. It also drops the following files in the Windows system folder:

  • CMD.COM
  • NETSTAT.COM
  • PING.COM
  • REGEDIT.COM
  • TASKKILL.COM
  • TASKLIST.COM
  • TRACERT.COM

These files contain the string MZ so that this worm can disable the following Windows tool applications:

  • CMD.EXE
  • NETSTAT.EXE
  • PING.EXE
  • REGEDIT.EXE
  • TASKKILL.EXE
  • TASKLIST.EXE
  • TRACERT.EXE

For example when a user types CMD in Start>Run, the file CMD.COM gets executed instead of CMD.EXE because .COM files have a higher priority of execution than .EXE files.

It also disables the Task Manager from showing and drops the following non-malicious files in the root folder:

  • X.TXT
  • Z.TXT

This worm needs the file MSVBVM60.DLL in order to run properly.

Analysis By: Mark Anthony Balanza

Revision History:

First pattern file version: 2.630.01
First pattern file release date: May 12, 2005

SOLUTION


Minimum scan engine version needed: 6.810

Pattern file needed: 4.610.01

Pattern release date: Jul 21, 2007


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:

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.

Editing the Registry

This malware modifies the system's registry. Users affected by this malware may need to modify or delete specific registry keys or entries. For detailed information regarding registry editing, please refer to the following articles from Microsoft:

  1. HOW TO: Backup, Edit, and Restore the Registry in Windows 95, Windows 98, and Windows ME
  2. HOW TO: Backup, Edit, and Restore the Registry in Windows NT 4.0
  3. HOW TO: Backup, Edit, and Restore the Registry in Windows 2000
  4. HOW TO: Back Up, Edit, and Restore the Registry in Windows XP and 2003

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_CURRENT_USER>Software>Microsoft>
    Windows>CurrentVersion>Run
  3. In the right panel, locate and delete the entry:
    p2pnetwork = "p2pnetwork.exe"
  4. In the left panel, double-click the following:
    HKEY_CURRENT_USER>Software>Microsoft>
    Windows>CurrentVersion>RunServices
  5. In the right panel, locate and delete the entry:
    p2pnetwork = "p2pnetwork.exe"
  6. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>Software>Microsoft>
    Windows>CurrentVersion>Run
  7. In the right panel, locate and delete the entry:
    p2pnetwork = "p2pnetwork.exe"
  8. In the right panel, locate and delete the entry:
    HKEY_LOCAL_MACHINE>Software>Microsoft>
    Windows>CurrentVersion>RunServices
  9. In the right panel, locate and delete the entry:
    p2pnetwork = "p2pnetwork.exe"
  10. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>Software>Microsoft>
    Windows>CurrentVersion>Run
  11. In the right panel, locate and delete the entry:
    MsConfigs = "%Program files%\MsConfigs\MsConfigs.exe"
    (Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)

Removing Other Entries from the Registry

  1. Still in the Registry Editor, in the left panel, locate and delete the entry:
    HKEY_CURRENT_USER>Software>Microsoft>
    OLE
  2. In the right panel, locate and delete the entry:
    p2pnetwork = "p2pnetwork.exe"
  3. In the left panel, locate and delete the entry:
    HKEY_LOCAL_MACHINE>Software>Microsoft>
    OLE
  4. In the right panel, locate and delete the entry:
    p2pnetwork = "p2pnetwork.exe"
  5. In the left panel, locate and delete the entry:
    HKEY_CURRENT_USER>System>CurrentControlSet>
    Control>Lsa
  6. In the right panel, locate and delete the entry:
    p2pnetwork = "p2pnetwork.exe"
  7. In the left panel, locate and delete the entry:
    HKEY_LOCAL_MACHINE>System>CurrentControlSet>
    Control>Lsa
  8. In the right panel, locate and delete the entry:
    p2pnetwork = "p2pnetwork.exe"

Restoring Modified Entries in the Registry

  1. Still in the Registry Editor, in the left panel, double-click the entry:
    HKEY_LOCAL_MACHINE>Software>Microsoft>
    Ole
  2. In the right panel, locate and modify the value:
    FROM: EnableDCOM = "N"
    TO: EnableDCOM = "Y"
  3. Close Registry Editor.

Restoring EnableDCOM and RestrictAnonymous registry entries

This malware modifies EnableDCOM and RestrictAnonymous registry entries to a certain value. To know more about restoring these registries to their original values, please refer to these articles:

  1. COM security frequently asked questions
  2. How to disable DCOM support in Windows
  3. How to Use the RestrictAnonymous Registry Value in Windows 2000
  4. The "RestrictAnonymous" Registry Value May Break the Trust to a Windows 2000 Domain

Deleting Malware File

  1. Right-click Start then click Search� or Find�, depending on the version of Windows you are running.
  2. In the Named input box, type:
    x.txt
  3. In the Look In drop-down list, select the drive that contains Windows, then press Enter.
  4. Once located, select the file then press Delete.
  5. Repeat the process for the following files:
    • cmd.com
    • netstat.com
    • ping.com
    • regedit.com
    • taskkill.com
    • tasklist.com
    • tracert.com
    • z.txt

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 set(s).

Running Trend Micro Antivirus

Scan your system with Trend Micro antivirus and delete files detected as WOMR_ALCAN.A. 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 online virus scanner.




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