Analysis by: Sabrina Lei Sioting
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This worm arrives by connecting affected removable drives to a system.

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

Tamaño del archivo 758,272 bytes
Tipo de archivo EXE
Residente en memoria Yes
Fecha de recepción de las muestras iniciales 05 Mar 2009

Arrival Details

This worm arrives by connecting affected removable drives to a system.

Installation

This worm drops the following copies of itself into the affected system:

  • %System Root%\autorun.pif
  • %Windows%\svchost.exe

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

Autostart Technique

This worm registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_TRKNETSSVCS\
0000
Service = "TrkNetsSvcs"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_TRKNETSSVCS\
0000
DeviceDesc = "Distributed Link Tracking Servers"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_TRKNETSSVCS\
0000\Control
ActiveService = "TrkNetsSvcs"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TrkNetsSvcs
ImagePath = "%Windows%\svchost.exe -netsvcs"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TrkNetsSvcs
DisplayName = "Distributed Link Tracking Servers"

Other System Modifications

This worm adds the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_TRKNETSSVCS

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TrkNetsSvcs

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_TRKNETSSVCS\
0000

It creates the following registry entry(ies) to bypass Windows Firewall:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%WINDOWS%\svchost.exe = "%WINDOWS%\svchost.exe:*:Enabled:svchost.exe"

Propagation

This worm drops the following copy(ies) of itself in all removable drives:

  • autorun.pif

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

The said .INF file contains the following strings:

[AutoRun]
open=autorun.pif
shell\1=´ò¿ª(&O)
shell\1\Command=autorun.pif
shell\2\=ä¯ÀÀ(&B)
shell\2\Command=autorun.pif
shellexecute=autorun.pif

Other Details

This worm deletes the initially executed copy of itself