BKDR_ANDROM.YYPL

 Analysis by: John Anthony Banes

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet


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

  TECHNICAL DETAILS

File Size:

88,009,954 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

07 Aug 2017

Payload:

Connects to URLs/IPs

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 adds the following processes:

  • msiexec.exe

It injects itself into the following processes as part of its memory residency routine:

  • created msiexec.exe

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

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
  • 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

  SOLUTION

Minimum Scan Engine:

9.850

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

[ Learn More ]

Step 4

Search and delete these files

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.  
  • %User Temp%\KB{8 random numbers}.exe
  • %User Temp%\cdo{random number}.dll

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_ANDROM.YYPL. 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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