BKDR_EMDIVI.PMS

This backdoor arrives as an attachment to email messages spammed by other malware/grayware or malicious users. 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 runs certain commands that it receives remotely from a malicious user. Doing this puts the affected computer and information found on the computer at greater risk.

Arrival Details

This backdoor arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

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

• %User Temp%\vmwere.exe

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It drops the following non-malicious files:

• %User Temp%\kptl.doc - decoy document file

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

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

• fee87caf97c39d8da78d66f26c0537c6

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:

• %Start Menu%\Programs\Startup\vmwere.lnk (Windows Vista and higher versions)
• %Common Startup%\vmwere.lnk (Versions lower than Windows Vista)

(Note: %Start Menu% is the Start Menu folder, where it usually is C:\Documents and Settings\{user name}\Start Menu on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %Common Startup% is the system's shared Startup folder, which is usually C:\Documents and Settings\All Users\Start Menu\Programs\Startup on Windows 2000, XP, and Server 2003.)

Propagation

This backdoor does not have any propagation routine.

Backdoor Routine

This backdoor executes the following command(s) 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
• Gather credentials using CredEnumerate or PStoreCreateInstance API
• 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}n.biz/wp-content/plugins/akismet/state/index.php
• http://www.{BLOCKED}to.jp/html/mainland/index.php
• http://www.{BLOCKED}hool.com/trouble/fuck/you/index.php

Other Details

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

• http://www.microsoft.com
• http://www.msftncsi.com
• http://www.yahoo.co.jp

NOTES:

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

• Ollydbg
• Process Explorer
• Process Hacker
• Process Monitor
• SoftICE
• W32Dasm
• WireShark

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

It has a document icon and drops the non-malicious file kptl.doc. It will then open the file kptl.doc to deceive users that it is a normal file.

It does not have rootkit capabilities.

It does not exploit any vulnerability.