BKDR_DLDR.A

This backdoor arrives as a dropped malware. It is an Enfal/Lurid malware that has been used in other targeted attacks in the past. This backdoor's dropper, TROJ_ARTIEF.SDY, comes as a .DOC file attachment to spammed email about the Hurricane Sandy devastation.

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

For the related story, you may read the blog post NATO's NSHQ Targeted by Attack Leveraging Hurricane Sandy

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_ARTIEF.SDY

Installation

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

• %User Temp%\adobeupd.exe

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

It adds the following mutexes to ensure that only one of its copies runs at any one time:

• HTTPS-GNIK
• MAINHTTPS
• RMTCURR

Autostart Technique

This backdoor drops the following shortcut pointing to its copy in the User Startup folder to enable its automatic execution at every system startup:

• %User Startup%\Adobe Center.lnk
• All Users' %User Startup%\Adobe Center.lnk

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

• Download files from C&C server
• Upload files to C&C server
• Enumerate drives
• Get drive information
• Enumerate files/folders
• Find files/folders
• Get file information
• Create files/folders
• Modify files/folders
• Copy files/folders
• Delete files/folders
• Execute files
• Terminate processes
• Get time zone information
• Perform remote shell
• Sleep for a specified amount of time

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

• https://domain.{BLOCKED}2.us

It posts the following information to its command and control (C&C) server:

• Host name
• MAC address
• OS version information