Conficker Worm: Characteristics(contd.)

When executed, the worm copies itself using a random name to the %Sysdir% folder.
(Where %Sysdir% is the Windows system folder; e.g. C:\Windows\System32)
It modifies the following registry key to create a randomly-named service on the affected syetem:

• HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\{random}\Parameters\”ServiceDll” = “Path to worm”

• HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\{random}\”ImagePath” = %SystemRoot%\system32\svchost.exe -k netsvcs

Attempts connections to one or more of the following websites to obtain the public ip address of the affected computer.

• http://www.getmyip.org
• http://getmyip.co.uk
• http://checkip.dyndns.org
• http://whatsmyipaddress.com

Starts a HTTP server on a random port on the infected machine to host a copy of the worm.
Continuously scans the subnet of the infected host for vulnerable machines and executes the exploit. If the exploit is successful, the remote computer will then connect back to the http server and download a copy of the worm.
Later variants of w32/Conficker.worm are using scheduled tasks and Autorun.inf file to replicate on to non vulnerable systems or to reinfect previously infected systems after they have been cleaned.