WORM_DISTTRACK.A

This worm has components that overwrites the affected computer's Master Boot Record (MBR).

To get a one-glance comprehensive view of the behavior of this Worm, refer to the Threat Diagram shown below.

This worm executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

Arrival Details

This worm may arrive via network shares.

Installation

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

• %System%\trksvr.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

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\
Services\TrkSvr
Type = "10"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TrkSvr
Start = "2"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TrkSvr
ErrorControl = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TrkSvr
ImagePath = "%System\trksvr.exe"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TrkSvr
DisplayName = "Distributed Link Tracking Server"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TrkSvr
DependOnService = "RpcSs"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TrkSvr
DependOnGroup = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TrkSvr
ObjectName = "LocalSystem"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TrkSvr
Description = "Enables the Distributed Link Tracking Client service within the same domain to provide more reliable and efficient maintenance of links within the domain. If this service is disabled, any services that explicitly depend on it will fail to start."

It registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TrkSvr

Other System Modifications

This worm adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\lanmanworkstation
DependOnService = "TrkSvr"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\lanmanworkstation
DependOnGroup = "0"

Propagation

This worm drops copies of itself in the following shared folders:

• \\{IP address}\ADMIN$\system32\{random file name}.exe
• \\{IP address}\C$\WINDOWS\system32\{random file name}.exe
• \\{IP address}\D$\WINDOWS\system32\{random file name}.exe
• \\{IP address}\E$\WINDOWS\system32\{random file name}.exe

Dropping Routine

This worm drops the following files:

• %System%\{random file name}.exe - detected by Trend Micro as TROJ_WIPMBR.A
• %System%\netinit.exe - detected by Trend Micro as TROJ_DISTTRACK.A

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

NOTES:

If command-line parameters are specified, this worm drops copies of itself to the following:

• \\{command-line parameter}\ADMIN$\system32\{random file name}.exe
• \\{command-line parameter}\C$\WINDOWS\system32\{random file name}.exe
• \\{command-line parameter}\D$\WINDOWS\system32\{random file name}.exe
• \\{command-line parameter}\E$\WINDOWS\system32\{random file name}.exe

{random file name} is randomly selected from the following:

• caclsrv
• certutl
• clean
• ctrl
• dfrag
• dnslookup
• dvdquery
• event
• extract
• findfile
• fsutl
• gpget
• iissrv
• ipsecure
• msinit
• netx
• ntdsutl
• ntfrsutil
• ntnw
• power
• rdsadmin
• regsys
• routeman
• rrasrv
• sacses
• sfmsc
• sigver
• smbinit
• wcscript