Analysis by: Byron Jon Gelera

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel: 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 may be dropped by other malware.

It deletes registry entries, causing some applications and programs to not function properly.

It does not have any propagation routine.

It executes commands from a remote malicious user, effectively compromising the affected system. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

Payload: Connects to URLs/IPs, Downloads files, Steals information

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.

It may be dropped by the following malware:

Installation

This Backdoor adds the following processes:

  • msiexec.exe

It injects codes into the following process(es):

  • created msiexec.exe

Other System Modifications

This Backdoor deletes the following registry entries:

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
taskmgr.exe
Debugger = "taskmgr.exe"

Propagation

This Backdoor does not have any propagation routine.

Backdoor Routine

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

  • Start a Process
  • Download a file directed by C&C server, save it as %User Temp%\KB{8 random numbers}.exe and execute it
  • Copy %System%\cdosys.dll to %User Temp%\cdo{random number}.dll and load it
  • Uninstall itself

(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.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

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

  • http://{BLOCKED}entia.ru/diff.php
  • http://{BLOCKED}trivia.ru/atomic.php

However, as of this writing, the said sites are inaccessible.

Information Theft

This Backdoor gathers the following data:

  • Root Volume Serial Number
  • Operating System Version
  • Local IP Address
  • Administrator privileges

Other Details

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

  • update.microsoft.com
  • microsoft.com
  • google.com
  • bing.com
  • yahoo.com

It does the following:

  • Checks if the following processes related to virtual environment, emulation software, and network monitoring software are running in the affected machine. If so, it will perform infinite sleep.
    • avpui.exe
    • filemon.exe
    • netmon.exe
    • perl.exe
    • prl_cc.exe
    • prl_tools_service.exe
    • prl_tools.exe
    • procmon.exe
    • python.exe
    • regmon.exe
    • sandboxiedcomlaunch.exe
    • sandboxierpcss.exe
    • sharedintapp.exe
    • vboxservice.exe
    • vboxtray.exe
    • vmsrvc.exe
    • vmtoolsd.exe
    • vmusrvc.exe
    • vmwareservice.exe
    • vmwareuser.exe
    • wireshark.exe
  • It will not proceed with its routine if the system's language is any of the following:
    • Russian
    • Ukrainian
    • Belarusian
    • Kazakh
  • Connects to the following Network Time Protocol (NTP) servers:
    • pool.ntp.org
    • africa.pool.ntp.org
    • oceania.pool.ntp.org
    • asia.pool.ntp.org
    • south-america.pool.ntp.org
    • north-merica.pool.ntp.org
    • europe.pool.ntp.org
  • It will not proceed with its routine if the current filename of the malware is any of the following:
    • C:\t.exe
    • C:\myapp.exe
    • C:\self.exe
    • C:\file.exe
    • C:\sample.exe

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.584.08
FIRST VSAPI PATTERN DATE: 09 Aug 2017
VSAPI OPR PATTERN File: 13.585.00
VSAPI OPR PATTERN Date: 10 Aug 2017

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

Identify and terminate files detected as BKDR_ANDROM.SMRA

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

Scan your computer with your Trend Micro product to delete files detected as BKDR_ANDROM.SMRA. 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.

Step 5

Restore this deleted registry key/value from backup

*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

 
  • In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\taskmgr.exe
    • Debugger = "taskmgr.exe"


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