BKDR_EMDIVI.ZJCH-A

This malware is related to an active campaign that compromised Japanese websites and used these as C&C servers of EMDIVI Backdoor.

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

This backdoor may arrive bundled with malware packages as a malware component. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It does not have any propagation routine.

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

It retrieves specific information from the affected system.

Arrival Details

This backdoor may arrive bundled with malware packages as a malware component.

It 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 adds the following processes:

• svchost.exe

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

• 58e034ea0c370efbd9c8764ebf8bd197
• iL463655Oh75jM578996Pd675475

It injects codes into the following process(es):

• created svchost.exe

Propagation

This backdoor does not have any propagation routine.

Backdoor Routine

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

• Enumerate files and folders
• Delete files and folders
• Download files
• Upload files
• Execute files
• Get file attributes
• Enumerate processes
• Perform remote shell
• Loads a library using LoadLibrary API
• Import functions from a library using GetProcAddress API
• Choose HTTP Authentication
• Setup Proxy auto-configuration
• Gather Firefox settings from prefs.js
• Gather proxy settings from proxy.pac
• Gather proxy settings from windows registry
• Sleep

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

• http://www.{BLOCKED}m.jp/index.php
• http://www.{BLOCKED}norei.com/?page={3 random numbers}
• http://jp.{BLOCKED}a.org/?p={2 random numbers}
• hxxp://2e53007.{BLOCKED}nd.com

Information Theft

This backdoor retrieves the following information from the affected system:

• Host name
• Process ID of the malware
• Memory Size (RAM)
• Internet Explorer Version
• Windows OS Version
• System Language
• Location
• Time Zone Information

Other Details

This backdoor connects to the following URL(s) to check for an Internet connection:

• http://www.msftncsi.com/ncsi.txt
• http://www.microsoft.com/en-us/default.aspx
• http://www.yahoo.co.jp

It requires the following additional components to properly run:

• {malware path}\iusb3mon.dll ← used to decrypt and load itself; detected as TROJ_EMDIVI.ZJCH-A

NOTES:

This backdoor does not execute properly if the hostname is similar to any of the following strings:

• wilbert-SC1508
• xp-sp3-template
• mip-xp-cht
• CWS01_03
• wilbert-SC2202
• dc-filesrv
• Atony-PC
• brbrb-d8fb22af1
• placehol-6f699a

It enumerates all visible windows and compares each window's title bar text with the following strings:

• OllyDbg
• W32Dasm
• Wireshark
• Fiddler
• SoftICE
• Process Explorer
• Process Monitor
• Process Hacker

If a window's title bar text contains any of the said strings, it pauses the execution of its malicious routine by performing a Sleep command.