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TrojanSpy.Win32.KEYLOG.AH

February 13, 2020
 PLATFORM:

Windows

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

1,241,088 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

13 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 adds the following processes:

  • cmd.exe /c %User Temp%\sub21_12.gif
  • %User Startup%\bxjrrkch.exe
  • %User Temp%\sub21_12.gif %User Temp%\sub21_12.gif
  • "%System Root%\Program Files\Internet Explorer\iexplore.exe" %User Temp%\sub21_12.gif
  • %User Temp%\sub21_12.gif
  • "%Program Files%\Internet Explorer\IEXPLORE.EXE" SCODEF:2776 CREDAT:275457 /prefetch:2

(Note: %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).. %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows 2003(32-bit), XP and 2000(32-bit), or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit), 10(64-bit).. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000(32-bit), Server 2003(32-bit), XP, Vista(64-bit), 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit) , or C:\Program Files (x86) in Windows XP(64-bit), Vista(64-bit), 7(64-bit), 8(64-bit), 8.1(64-bit), 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It creates the following folders:

  • %Application Data%\Microsoft\Windows\DNTException
  • %Application Data%\Microsoft\Windows\PrivacIE
  • %Application Data%\Microsoft\Windows\IECompatCache
  • %AppDataLocal%\Microsoft\Internet Explorer\Recovery\High\Active
  • %Application Data%\Microsoft\Windows\IECompatUACache

(Note: %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).. %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).)

Other System Modifications

This Trojan Spy adds the following registry entries:

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
%User Temp%\namebro
namebro = "bxjrrkch"

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
%User Temp%\Text1
Text1 = ""

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
%User Temp%\Text1
Text1 = "4"

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
%User Temp%\Text1
Text1 = "59"

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
%User Temp%\Text1
Text1 = "0"

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
%User Temp%\Text1
Text1 = "perwa{computername}"

It deletes the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Ext\
Settings\{72853161-30C5-4D22-B7F9-0BBC1D38A37E}\NewInstallPromptCount

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Ext\
Settings\{72853161-30C5-4D22-B7F9-0BBC1D38A37E}\CompatBlockPromptCount

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Ext\
Settings\{761497BB-D6F0-462C-B6EB-D4DAF1D92D43}\NewInstallPromptCount

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Ext\
Settings\{761497BB-D6F0-462C-B6EB-D4DAF1D92D43}\CompatBlockPromptCount

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Ext\
Settings\{DBC80044-A445-435B-BC74-9C25C1C588A9}\NewInstallPromptCount

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Ext\
Settings\{DBC80044-A445-435B-BC74-9C25C1C588A9}\CompatBlockPromptCount

Dropping Routine

This Trojan Spy drops the following files:

  • %User Temp%\sub21_12.gif
  • %AppDataLocal%\Microsoft\Internet Explorer\Recovery\High\Active\RecoveryStore.{219FE7B0-ECB2-11E9-B5A7-005056BC5D48}.dat

(Note: %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).. %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).)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.850

Step 1

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 2

Identify and terminate files detected as TrojanSpy.Win32.KEYLOG.AH

[ 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 3

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\VB and VBA Program Settings\%User Temp%\namebro
    • namebro = "bxjrrkch"
  • In HKEY_CURRENT_USER\Software\VB and VBA Program Settings\%User Temp%\Text1
    • Text1 = ""
  • In HKEY_CURRENT_USER\Software\VB and VBA Program Settings\%User Temp%\Text1
    • Text1 = "4"
  • In HKEY_CURRENT_USER\Software\VB and VBA Program Settings\%User Temp%\Text1
    • Text1 = "59"
  • In HKEY_CURRENT_USER\Software\VB and VBA Program Settings\%User Temp%\Text1
    • Text1 = "0"
  • In HKEY_CURRENT_USER\Software\VB and VBA Program Settings\%User Temp%\Text1
    • Text1 = "perwa{computername}"

Step 4

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%\sub21_12.gif
  • %AppDataLocal%\Microsoft\Internet Explorer\Recovery\High\Active\RecoveryStore.{219FE7B0-ECB2-11E9-B5A7-005056BC5D48}.dat

Step 5

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %Application Data%\Microsoft\Windows\DNTException
  • %Application Data%\Microsoft\Windows\PrivacIE
  • %Application Data%\Microsoft\Windows\IECompatCache
  • %AppDataLocal%\Microsoft\Internet Explorer\Recovery\High\Active
  • %Application Data%\Microsoft\Windows\IECompatUACache

Step 6

Scan your computer with your Trend Micro product to delete files detected as TrojanSpy.Win32.KEYLOG.AH. 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 the following Trend Micro Support pages for more information:

Step 7

Restore these deleted registry keys/values 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\CurrentVersion\Ext\Settings\{72853161-30C5-4D22-B7F9-0BBC1D38A37E}
    • NewInstallPromptCount
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Ext\Settings\{72853161-30C5-4D22-B7F9-0BBC1D38A37E}
    • CompatBlockPromptCount
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Ext\Settings\{761497BB-D6F0-462C-B6EB-D4DAF1D92D43}
    • NewInstallPromptCount
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Ext\Settings\{761497BB-D6F0-462C-B6EB-D4DAF1D92D43}
    • CompatBlockPromptCount
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Ext\Settings\{DBC80044-A445-435B-BC74-9C25C1C588A9}
    • NewInstallPromptCount
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Ext\Settings\{DBC80044-A445-435B-BC74-9C25C1C588A9}
    • CompatBlockPromptCount


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