Threat Encyclopedia

Selected viruses, spyware, and other threats: sorted alphabetically

You can download the removal tool here .
Short description
Win32/Conficker.AE is a worm that spreads via shared folders and on removable media. It connects to remote machines in attempt to exploit the Server Service vulnerability.
Installation
When executed, the worm copies itself in some of the the following locations:
  • %system%\%variable%.dll
  • %programfiles%\Internet Explorer\%variable%.dll
  • %programfiles%\Movie Maker\%variable%.dll
  • %appdata%\%variable%.dll
  • %temp%\%variable%.dll
A string with variable content is used instead of %variable% .

The worm loads and injects the %variable%.dll library into the following processes:
  • explorer.exe
  • services.exe
  • svchost.exe
The worm registers itself as a system service with the name combined from the following strings:
  • Boot
  • Center
  • Config
  • Driver
  • Helper
In order to be executed on every system start, the worm sets the following Registry entry:
  • [HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\
    CurrentVersion\Run]
    "%variable_name%" = "rundll32.exe "%system%\
    %variable%.dll",%random_string%"
The following Registry entries are set:
  • [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\%random
    service name%\Parameters]
    "ServiceDll" = "%system%\%variable%.dll"
  • [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\%random
    service name%]
    "Image Path" = "%System Root%\system32\svchost.exe -k netsvcs"
A string with variable content is used instead of %random service name% .

The following Registry entries are removed:
  • [HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\
    CurrentVersion\explorer\ShellServiceObjects\
    {FD6905CE-952F-41F1-9A6F-135D9C6622CC}]
  • [HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\
    CurrentVersion\Run]
    "Windows Defender" = "%filepath%"
Spreading
The worm starts a HTTP server on a random port.

By connecting to remote machines to port TCP 139, 445 it tries to exploit the Server Service .

If successful, the remote computer attempts to connect to the infected computer and download a copy of the worm .

It is a DLL library with the following extension:
  • .bmp
  • .gif
  • .jpeg
  • .png


This vulnerability is described in Microsoft Security Bulletin MS08-067 .
Spreading via shared folders
The worm tries to copy itself into shared folders of machines on a local network.

The following usernames are used:
  • %username%
The following passwords are used:
  • 123
  • 1234
  • 12345
  • 123456
  • 1234567
If successful the following filename is used:
  • \\%hostname%\ADMIN$\System32\%variable%.dll
The worm schedules a task that causes the following file to be executed daily:
  • rundll32.exe %variable%.dll, %random_string%
Spreading on removable media
The worm copies itself into existing folders of removable drives.

If successful the following filename is used:
  • %drive%\RECYCLER\S-%variable1%\%variable2%.%variable3%
A string with variable content is used instead of %variable1-3% .

The worm creates the following file:
  • %drive%\autorun.inf
Thus, the worm ensures it is started each time infected media is inserted into the computer.
Other information
The following services are disabled:
  • Windows Security Center Service (wscsvc)
  • Windows Automatic Update Service (wuauserv)
  • Background Intelligent Transfer Service (BITS)
  • Windows Defender Service (WinDefend)
  • Windows Error Reporting Service (ERSvc)
  • Windows Error Reporting Service (WerSvc)
The worm launches the following processes:
  • netsh interface tcp set global autotuning=disabled
The worm blocks access to any domains that contain any of the following strings in their name:
  • ahnlab
  • arcabit
  • avast
  • avira
  • castlecops
If the current system date and time matches certain conditions, the worm will attempt to download several files from the Internet. The files are then executed.

The worm runs only encrypted and properly signed files.

These are stored in the following locations:
  • %temp%\%variable%.tmp
A string with variable content is used instead of %variable% .

The worm may set the following Registry entries:
  • [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\
    SharedAccess\Parameters\FirewallPolicy\StandardProfile\
    GloballyOpenPorts\List]
    "%port number%:TCP" = "%port number%:TCP:*:Enabled:%variable%"
The performed data entry creates an exception in the Windows Firewall program.

The worm connects to the following addresses:
  • http://checkip.dyndns.org
    http://www.whatismyip.org
    http://www.whatsmyipaddress.com
    http://www.getmyip.org