WORM_DOORCAR.VI

This worm performs commands from a remote malicious user.

It also terminates itself if it is running under a Debugger or an Emulator. It also checks if the affected system uses certain display adapters.

This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Arrival Details

This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

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

• %User Profile%\Application Data\Realhost.exe
• %System%\host.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.. %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 adds the following mutexes to ensure that only one of its copies runs at any one time:

• mnUXsx75Xusnv

It terminates itself if it finds the following processes in the affected system's memory:

• CAIN
• FILEMON
• NETMON
• NETSTAT
• PROCMON
• REGMON
• TCPVIEW
• WIRESHARK

Autostart Technique

This worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Windows PC Driver = %User Profile%\Application Data\Realhost.exe

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
Windows-Network = %System%\host.exe

Other System Modifications

This worm adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
EnableBalloonTips = 0

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
EnableLUA = 0

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
EnableLUA = 0

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = 2

(Note: The default value data of the said registry entry is 1.)

Backdoor Routine

This worm connects to the following URL(s) to send and receive commands from a remote malicious user:

• http://{BLOCKED}n.pf-control.de/bot/gate.php

NOTES:

It may perform the following commands from a remote malicious user:

• Connects to malicious sites to download files/update of itself
• Launches the following attacks:
  HTTP flood
  ICMP flood
  SYN flood
  UDP flood
• Propagates itself in network and removable drives by attaching itself to archives with .RAR and .ZIP extension names

It also terminates itself if it is running under a Debugger or an Emulator. It also checks if the affected system uses any of the following display adapters:

• Parallels Video Adapter
• S3 Trio32/64
• VirtualBox Graphics Adapter
• VM Additions S3 Trio32/64
• VMware SVGA II