BKDR_SMALL.LEC

This {insert malware/spyware type} uses social engineering methods to lure users into performing certain actions that may, directly or indirectly, cause malicious routines to be performed. Specifically, it uses Trend Micro to lure users that the package came from a real antivirus company.

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

This backdoor may be dropped by other malware.

It executes commands from a remote malicious user, effectively compromising the affected system.

Arrival Details

This backdoor may be dropped by the following malware:

• TROJ_DROPPER.JAS

Installation

This backdoor is injected into the following processes running in memory:

• SVCHOST.EXE

Autostart Technique

This backdoor 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\Ias\Parameters
ServiceDll = "%System%\Iasex.dll"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Nwsapagent\Parameters
ServiceDll = "%System%\Nwsapagentex.dll"

Backdoor Routine

This backdoor opens the following port(s) where it listens for remote commands:

• TCP port 443

It executes the following commands from a remote malicious user:

• Capture screen shots
• Clear event logs
• Copy data from clipboard
• Enumerate files on local drives
• Log keystrokes
• Start and stop certain services

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

• {BLOCKED}.{BLOCKED}.84.234
• {BLOCKED}.{BLOCKED}.174.135
• {BLOCKED}w.{BLOCKED}ecs.com.tw
• {BLOCKED}y.{BLOCKED}ecs.com.tw
• {BLOCKED}r.{BLOCKED}ecs.com.tw