Analysis by: John Donnie Celestre
ALIASES:

N/A

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Dropped by other malware, 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.

  TECHNICAL DETAILS

File Size: 606,208 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 29 May 2018
Payload: Connects to URLs/IPs, Compromises system security, 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.

Installation

This Backdoor drops the following file(s)/component(s):

  • %Application Data%\Remc\logs.dat <- component file
  • %User Temp%\install.vbs <- executes the dropped copy of the malware
  • %User Temp%\~{random alphanumeric}.TMP <- component file

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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.. %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 copies of itself into the affected system:

  • %Application Data%\Remc\Remc.exe

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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 creates the following folders:

  • %Application Data%\Remc

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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:

  • ophjgkjfmv-8RQED1
  • Remcos_Mutex_Inj
  • Mutex_RemWatchdog

It terminates the execution of the copy it initially executed and executes the copy it drops instead.

Autostart Technique

This Backdoor adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\run
{random alphanumeric} = %Application Data%\Remc\Remc.exe

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random alphanumeric} = "%Application Data%\Remc\Remc.exe"

It modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Userinit = %System%\userinit.exe, "%Application Data%\Remc\Remc.exe"

(Note: The default value data of the said registry entry is %System%\userinit.exe.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = explorer.exe, "%Application Data%\Remc\Remc.exe"

(Note: The default value data of the said registry entry is explorer.exe.)

Other System Modifications

This Backdoor adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\run

HKEY_CURRENT_USER\Software\{random string}-{random string}

It adds the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\Software\{random string}-{random string}
EXEpath = {random hex values}

HKEY_CURRENT_USER\Software\{random string}-{random string}
WD = {random value}

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
EnableLUA = "0"

(Note: The default value data of the said registry entry is 1.)

Backdoor Routine

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

  • {BLOCKED}.{BLOCKED}.78.71:2442
  • {BLOCKED}.{BLOCKED}.9.122:2442
  • http://civita2.{BLOCKED}p.biz

Information Theft

This Backdoor gathers the following data:

  • Computer Name
  • System Type
  • Product Name
  • Primary Adapter
  • User Access (Admin or Non-admin)
  • User Profile
  • User Name
  • User Domain
  • Processor Revision No.
  • Processor Level
  • Processor Identifier
  • Processor Architecture
  • System Type (32-bit or 64-bit)

Other Details

Based on analysis of the codes, it has the following capabilities:

  • Perform ping
  • Enumerate drives
  • List all files
  • Open file/s
  • Get file/s from affected computer
  • Upload file/s to affected computer
  • Delete file/s from affected computer
  • Rename file/s from affected computer
  • Create new directory
  • Search a file from affected computer
  • Download file from url
  • Download file from local
  • Enumerate process
  • Terminate process
  • Maximize/Minimize application
  • Switch application
  • Terminate application
  • Open cmd
  • Open webpage
  • Open screen capture
  • Open keylogger
  • Set affected computer to send logs automatically
  • Deletes cookies and stored browser logins
  • Get screenshot
  • Capture image from camera if available
  • Capture voice from mic if available
  • Acquire user password
  • Display a messagebox to affected computer
  • Sends keyboard input
  • Sends mouse click
  • Shutdown affected Computer
  • Copy clipboard data
  • Set clipboard data
  • Clear clipboard data
  • Manipulate registry entries

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.282.05
FIRST VSAPI PATTERN DATE: 29 May 2018
VSAPI OPR PATTERN File: 14.283.00
VSAPI OPR PATTERN Date: 30 May 2018

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

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software
    • {random string}-{random string}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • run

Step 5

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • {random alphanumeric} = "%Application Data%\Remc\Remc.exe"

Step 6

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: Shell = explorer.exe, "%Application Data%\Remc\Remc.exe"
      To: Shell = explorer.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: Userinit = %System%\userinit.exe, "%Application Data%\Remc\Remc.exe";
      To: Userinit = %System%\userinit.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
    • From: EnableLUA = "0"
      To: EnableLUA = 1

Step 7

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.
  • %Application Data%\Remc\Remc.exe
  • %Application Data%\Remc\logs.dat
  • %User Temp%\~{random alphanumeric}.TMP

Step 8

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