BKDR_IRCBOT.DCD

This backdoor 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 backdoor 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 backdoor drops the following copies of itself into the affected system and executes them:

• %Application Data%\winsvrn32.exe

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

It terminates the execution of the copy it initially executed and executes the copy it drops instead.

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Microsoft Corp Update = "%Application Data%\winsvrn32.exe"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%Application Data%\winsvrn32.exe = "%Application Data%\winsvrn32.exe:*:Enabled:Microsoft Corp Update"

Other Details

This backdoor connects to the following possibly malicious URL:

• {BLOCKED}al.net
• {BLOCKED}supdatecenter.net