PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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: 910,336 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 05 Aug 2016

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.

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Mozilla Firefox = "%User Profile%\application data\{malware file name}"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{131AA660-7A2E-15J8-8266-0627V7LYJ7CL}
StubPath = "%User Temp%\Host.exe "

Other System Modifications

This backdoor deletes the following files:

  • %System Root%\aspr_keys.ini
  • %User Profile%\10.0\ReaderMessages-journal

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

It adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{131AA660-7A2E-15J8-8266-0627V7LYJ7CL}

HKEY_CURRENT_USER\Software\Adobe\
Adobe Acrobat\10.0

HKEY_CURRENT_USER\Software\Adobe\
Adobe Synchronizer\10.0

HKEY_LOCAL_MACHINE\System\Acrobatbrokerserverdispatchercpp789

HKEY_CURRENT_USER\Software\Adobe\
Acrobat Reader\10.0\Installer\
Migrated

HKEY_CURRENT_USER\Software\Adobe\
Acrobat Reader\10.0\Originals

HKEY_CURRENT_USER\Software\Adobe\
Acrobat Reader\10.0\AVGeneral

HKEY_LOCAL_MACHINE\Software\Adobe\
Acrobat Reader\10.0\AdobeViewer

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Adobe\
Acrobat Reader\10.0\Installer\
Migrated
{AC76BA86-7AD7-1033-7B44-AA0000000001} = "1"

HKEY_CURRENT_USER\Software\Adobe\
Acrobat Reader\10.0\Originals
bDisplayedSplash = "1"

HKEY_CURRENT_USER\Software\Adobe\
Acrobat Reader\10.0\AVGeneral
bLastExitNormal = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Adobe\
Acrobat Reader\10.0\AdobeViewer
EULA = "1"

HKEY_CURRENT_USER\Software\Adobe\
Acrobat Reader\10.0\AdobeViewer
EULA = "1"

Dropping Routine

This backdoor drops the following files:

  • %User Temp%\INVOICE.docx
  • %User Temp%\MOFTAH
  • %User Temp%\MOFTAHTO
  • %User Temp%\KOS
  • %User Temp%\MAIMO
  • %User Temp%\DATOS
  • %User Temp%\BMAIMO
  • %User Temp%\KATOS
  • %User Temp%\Host.exe
  • %User Temp%\PO2364482.pdf
  • %User Temp%\.Identifier
  • %Application Data%\Adobe\Color\ACECache11.lst
  • %Application Data%\Adobe\Acrobat\10.0\UserCache.bin
  • %User Profile%\application data\{malware file name}

(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.. %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 Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

Other Details

This backdoor connects to the following possibly malicious URL:

  • {BLOCKED}.221.7

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.8

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

Restart in Safe Mode

[ Learn More ]

Step 3

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components
    • {131AA660-7A2E-15J8-8266-0627V7LYJ7CL}
  • In HKEY_CURRENT_USER\Software\Adobe\Adobe Acrobat
    • 10.0
  • In HKEY_CURRENT_USER\Software\Adobe\Adobe Synchronizer
    • 10.0
  • In HKEY_LOCAL_MACHINE\System
    • Acrobatbrokerserverdispatchercpp789
  • In HKEY_CURRENT_USER\Software\Adobe\Acrobat Reader\10.0\Installer
    • Migrated
  • In HKEY_CURRENT_USER\Software\Adobe\Acrobat Reader\10.0
    • Originals
  • In HKEY_CURRENT_USER\Software\Adobe\Acrobat Reader\10.0
    • AVGeneral
  • In HKEY_LOCAL_MACHINE\Software\Adobe\Acrobat Reader\10.0
    • AdobeViewer

Step 4

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
    • Mozilla Firefox = "%User Profile%\application data\{malware file name}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{131AA660-7A2E-15J8-8266-0627V7LYJ7CL}
    • StubPath = "%User Temp%\Host.exe "
  • In HKEY_CURRENT_USER\Software\Adobe\Acrobat Reader\10.0\Installer\Migrated
    • {AC76BA86-7AD7-1033-7B44-AA0000000001} = "1"
  • In HKEY_CURRENT_USER\Software\Adobe\Acrobat Reader\10.0\Originals
    • bDisplayedSplash = "1"
  • In HKEY_CURRENT_USER\Software\Adobe\Acrobat Reader\10.0\AVGeneral
    • bLastExitNormal = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Adobe\Acrobat Reader\10.0\AdobeViewer
    • EULA = "1"
  • In HKEY_CURRENT_USER\Software\Adobe\Acrobat Reader\10.0\AdobeViewer
    • EULA = "1"

Step 5

Search and delete these components

[ Learn More ]
There may be some components 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%\INVOICE.docx
  • %User Temp%\MOFTAH
  • %User Temp%\MOFTAHTO
  • %User Temp%\KOS
  • %User Temp%\MAIMO
  • %User Temp%\DATOS
  • %User Temp%\BMAIMO
  • %User Temp%\KATOS
  • %User Temp%\Host.exe
  • %User Temp%\PO2364482.pdf
  • %User Temp%\.Identifier
  • %Application Data%\Adobe\Color\ACECache11.lst
  • %Application Data%\Adobe\Acrobat\10.0\UserCache.bin
  • %User Profile%\application data\{malware file name}

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_NETWIREDRC.AY. 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 7

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %System Root%\aspr_keys.ini
  • %User Profile%\10.0\ReaderMessages-journal


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