WORM_ZOTOB.I

Malware type: Worm

Aliases: Net-Worm.Win32.Mytob.cm (Kaspersky), W32/Zotob.worm.d (McAfee), W32.Zotob.I (Symantec), Worm/Mytob.CM.1 (Avira), W32/Domwis-M (Sophos), Worm:Win32/Zotob.J (Microsoft)

In the wild: Yes

Destructive: No

Language: English

Platform: Windows 98, ME, NT, 2000, XP, Server 2003

Encrypted: No

Overall risk rating:

Reported infections:

Damage potential:

High

Distribution potential:

High

Description: 

This memory-resident worm takes advantage of the Microsoft Windows Plug and Play vulnerability to propagate across networks. For more information regarding this vulnerability, refer to the following Microsoft Web page:

Once this worm successfully exploits a target system, it opens a Trivial File Transfer Protocol (TFTP) service. Using the said service, it drops and executes a copy of this worm onto the system.

Note that the said propagation routine works only on Windows NT and 2000, because the Microsoft Windows Plug and Play vulnerability has inherent characteristics that prevent this worm from exploiting it in Windows XP and Server 2003.

It opens random ports to connect to an IRC (Internet Relay Chat) server and join a specific IRC channel. Once connected, it enables a remote malicious user to issue certain commands locally on an affected machine.

For additional information about this threat, see:

Description created: Aug. 21, 2005 9:53:12 AM GMT -0800


TECHNICAL DETAILS


File type: PE

Memory resident:  Yes

Size of malware: 18,432 bytes

Ports used: Random

Initial samples received on: Aug 21, 2005

Vulnerability used:  (MS05-039) Vulnerability in Plug and Play Could Allow Remote Code Execution and Elevation of Privilege (899588)

Payload 1: Compromises system security

Details:

Installation and Autostart Technique

Upon execution, this worm drops and executes a copy of itself in the Windows folder as HPSV.EXE. It then checks if the mutex S-Y-B-O-T-By-Sky-Dancer exists on an affected system. If the mutex is present, this worm deletes the originally executed file and terminates itself. Otherwise, it creates the mentioned mutex. The said action ensures that only one instance of the worm is running on the affected machine.

This worm creates the following registry entries to ensure its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
SyBot v2.1 By Sky-Dancer = "HPSV.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\RunServices
SyBot v2.1 By Sky-Dancer = "HPSV.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
SyBot v2.1 By Sky-Dancer = "HPSV.exe"

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Ole
SyBot v2.1 By Sky-Dancer = "HPSV.exe"

HKEY_CURRENT_USER\Software\Microsoft\OLE
SyBot v2.1 By Sky-Dancer = "HPSV.exe"

HKEY_CURRENT_USER\SYSTEM\CurrentControlSet\
Control\LSA
SyBot v2.1 By Sky-Dancer = "HPSV.exe"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\LSA
SyBot v2.1 By Sky-Dancer = "HPSV.exe"

On systems running Windows XP Service Pack 2, this worm also adds the following registry entry:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\FirewallPolicy\
DomainProfile\AuthorizedApplications\List
C:\WINDOWS\HPSV.exe = "C:\WINDOWS\HPSV.exe:*:Enabled:HPSV"

Propagation via Exploit

This worm takes advantage of the Microsoft Windows Plug and Play vulnerability to propagate across networks. For more information regarding this vulnerability, refer to the following Microsoft Web page:

Once this worm successfully exploits a target system, it opens a Trivial File Transfer Protocol (TFTP) service. Using the said service, it then drops and executes a copy of this worm onto the system.

Note that the said propagation routine works only on Windows NT and 2000, because the Microsoft Windows Plug and Play vulnerability has inherent characteristics that prevent this worm from exploiting it in Windows XP and Server 2003.

Backdoor Capabilities

This worm opens random ports to connect to the IRC (Internet Relay Chat) server sezen.aydankaya.org and join a specific IRC channel. Once connected, it enables a remote malicious user to issue the following commands locally on an affected machine:

  • Execute files
  • Get Microsoft Office 2000, XP, and Server 2003 serial numbers
  • Get network and system information
  • Perform IRC commands
  • Upload and download files

Other Details

This worm runs on Windows 98, ME, NT, 2000, XP, and Server 2003.

Analysis By: Alejandro Manalo

Revision History:

First pattern file version: 2.792.20
First pattern file release date: Aug 21, 2005
 

Aug 21, 2005 - Modified Virus Report
Aug 22, 2005 - Insertion of Automatic Removal Instructions

SOLUTION


Minimum scan engine version needed: 6.810

Pattern file needed: 2.797.00

Pattern release date: Aug 23, 2005


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:

AUTOMATIC REMOVAL INSTRUCTIONS

MANUAL REMOVAL INSTRUCTIONS

Terminating the Malware Program

This procedure terminates the running malware process.

If the process you are looking for is not in the list displayed by Task Manager, proceed to the succeeding solution set.

  1. Open Windows Task Manager.
    • On Windows 98 and ME, press
    CTRL%20ALT%20DELETE
    • On Windows NT, 2000, XP, and Server 2003, press
    CTRL%20SHIFT%20ESC, then click the Processes tab.
  2. In the list of running programs*, locate the process:
    HPSV.EXE
  3. Select the malware process, then press either the End Task or the End Process button, depending on the version of Windows on your system.
  4. To check if the malware process has been terminated, close Task Manager, and then open it again.
  5. Close Task Manager.

*NOTE: On systems running Windows 98 and ME, Windows Task Manager may not show certain processes. You can use a third party process viewer such as Process Explorer to terminate the malware process. Otherwise, continue with the next procedure, noting additional instructions. If you were not able to terminate the malware process as described in the previous procedure, restart your system.

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.

If the registry entries below are not found, the malware may not have executed as of detection. If so, proceed to the succeeding solution set.

  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:
    SyBot v2.1 By Sky-Dancer = "HPSV.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:
    SyBot v2.1 By Sky-Dancer = "HPSV.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:
    SyBot v2.1 By Sky-Dancer = "HPSV.exe"

Removing Other Entries from the Registry

  1. Still in the Registry Editor, in the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>OLE
  2. In the right panel, locate and delete the entry:
    SyBot v2.1 By Sky-Dancer = "HPSV.exe"
  3. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>SYSTEM>CurrentControlSet>
    Control>LSA
  4. In the right panel, locate and delete the entry:
    SyBot v2.1 By Sky-Dancer = "HPSV.exe"
  5. In the left panel, double-click the following:
    HKEY_CURRENT_USER>Software>Microsoft>OLE
  6. In the right panel, locate and delete the entry:
    SyBot v2.1 By Sky-Dancer = "HPSV.exe"
  7. In the left panel, double-click the following:
    HKEY_CURRENT_USER>SYSTEM>CurrentControlSet>
    Control>LSA
  8. In the right panel, locate and delete the entry:
    SyBot v2.1 By Sky-Dancer = "HPSV.exe"

Removing Other Entries from the Registry on Systems Running Windows 2000 Service Pack 2

  1. Again in the Registry Editor, in the left panel, double-click the following:
    HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\
    SharedAccess\Parameters\FirewallPolicy\DomainProfile\
    AuthorizedApplications\List
  2. In the right panel, locate and delete the entry:
    C:\WINDOWS\HPSV.exe = "C:\WINDOWS\HPSV.exe:*:Enabled:HPSV"
  3. Close Registry Editor.

Important 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 WORM_ZOTOB.I. To do this, Trend Micro customers must download the latest virus pattern file and scan their system. Other Internet users can use HouseCall, Trend Micro's online virus scanner.

Applying Patches

This malware exploits known vulnerabilities in Windows. Download and install the fix patch supplied by Microsoft. Refrain from using this product until the appropriate patch has been installed. Trend Micro advises users to download critical patches upon release by vendors.




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