BKDR_EMDIVI.POL
Backdoor.Emdivi (Symantec)
Windows
Threat Type: Backdoor
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
Downloaded from the Internet, Dropped by other malware
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.
It does not have any propagation routine.
It executes commands from a remote malicious user, effectively compromising the affected system.
TECHNICAL DETAILS
Varies
EXE
Yes
22 Oct 2014
Connects to URLs/IPs, Compromises system security, Drops files
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 component file(s):
- %User Temp%\kptl.doc - decoy document file
- %User Temp%\vmwere.exe - also detected as BKDR_EMDIVI.POL
(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:
- d10ab3dd12f7124d3d2ecc82b41225d2
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 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
- 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}ori.com/wp-includes/news/scripts/index.php
- http://www.{BLOCKED}to.jp/html/mainland/index.php
As of this writing, the said sites are inaccessible.
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.
SOLUTION
9.700
11.228.03
22 Oct 2014
11.229.00
23 Oct 2014
Step 1
Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.
Step 2
Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.
Step 3
Restart in Safe Mode
Step 4
Search and delete this file
- %Start Menu%\Programs\Startup\vmwere.lnk (Windows Vista and higher versions)
- %Common Startup%\vmwere.lnk (Versions lower than Windows Vista)
- %User Temp%\kptl.doc
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_EMDIVI.POL. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.
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