PLATFORM:

Windows

 OVERALL RISK RATING:
 REPORTED INFECTION:
 SYSTEM IMPACT RATING:
 INFORMATION EXPOSURE:

  • Threat Type: Hacking Tool

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Hacking Tool 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: 437,929 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 29 Jun 2019

Arrival Details

This Hacking Tool 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 Hacking Tool adds the following processes:

  • %System%\cmd.exe /v:on /e:on /a /c main.bat
  • %System%\cmd.exe /S /D /c" set path"
  • grep.efix -iq "%System Root%\Windows\system32;"
  • chcp
  • grep.efix -iq 950
  • %System Root%\NEFix\sed.EFix %System Root%\NEFix\sed.EFix /?
  • %System Root%\NEFix\grep.EFix %System Root%\NEFix\grep.EFix /?
  • %System Root%\NEFix\swreg.EFix %System Root%\NEFix\swreg.EFix /?
  • %System Root%\NEFix\more.com %System Root%\NEFix\more.com /?
  • nircmd.EFix execmd echo.
  • %System Root%\NEFix\CProcess.EFix cprocess.EFix /PMTEXT csrss.exe .\Temp\cprocess.1
  • swreg.EFix add "hklm\software\EFix" /F
  • swreg.EFix query "hklm\software\EFix"
  • swreg.efix delete "hkcu\Software\Microsoft\Windows\CurrentVersion\Policies\system" /v "disableregistrytools" /F
  • Fixreg.EFix /e ".\Temp\Fixreg.1" "HKEY_LOCAL_MACHINE\software\EFix"
  • %System%\cmd.exe /c swreg.efix query "hklm\system\select" /v "current"|sed.efix "/\t/!d ; s/.*\t// ; s/ .*//"
  • swreg.EFix export "HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders" ".\Temp\CF.1" /nt4
  • %System%\cmd.exe /c grep.efix -i "Desktop" .\Temp\CF.1|sed.efix "s/\\/\/g"
  • swreg.efix add "hklm\software\EFix" /v "Desktop" /t REG_SZ /d "%Desktop%" /F
  • swreg.EFix compare "HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders" "hklm\software\EFix" /v "desktop"
  • %System%\cmd.exe /c grep.efix -i "Startup" .\Temp\CF.1|sed "s/\\/\/g"
  • swreg.EFix add "hklm\software\EFix" /v "Startup" /t REG_SZ /d "%User Startup%" /F
  • swreg.EFix compare "HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders" "hklm\software\EFix" /v "startup"
  • swreg.efix export "HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders" ".\Temp\Iecache.1" /nt4
  • grep.efix -i "cache" .\Temp\CF.1
  • sed.efix "s/\"//g"
  • %System%\cmd.exe /c sed.efix -e "s/\\/\/g" .\Temp\CF.2|grep.efix -i "cache="
  • swreg.efix add "hklm\software\EFix" /v "cache" /t REG_SZ /d "%Temporary Internet Files%" /F
  • swreg.efix compare "HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders" "hklm\software\EFix" /v "cache"
  • swreg.EFix export "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders" ".\Temp\SF.1" /nt4
  • %System%\cmd.exe /c grep.efix -i "Common Startup" .\Temp\SF.1|sed.efix "s/\\/\/g"
  • swreg.EFix add "hklm\software\EFix" /v "Common Startup" /t REG_SZ /d "%All Users Profile%\Microsoft\Windows\Start Menu\Programs\Startup" /F
  • swreg.EFix compare "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders" "hklm\software\EFix" /v "Common Startup"
  • swreg.efix query "hklm\system\CurrentControlSet\Control\Session Manager\Environment"
  • sed.efix "/\t/!d ; s/ *//"
  • sed.efix "/^TEMP/I!d ; s/\t/=/g" .\Temp\temp1.1
  • swreg.efix add "hklm\software\EFix" /v "Temp" /t REG_EXPAND_SZ /d "%SystemRoot%\TEMP" /F
  • swreg.efix compare "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Environment" "hklm\software\EFix" /v "Temp"
  • sed.efix "/^TMP/I!d ; s/\t/=/g" .\Temp\temp1.1
  • swreg.efix add "hklm\software\EFix" /v "Tmp" /t REG_EXPAND_SZ /d "%SystemRoot%\TEMP" /F
  • swreg.efix compare "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Environment" "hklm\software\EFix" /v "Tmp"
  • nircmd.efix wait 1000
  • swreg.efix export "hklm\system\mounteddevices" ".\Temp\devices.1" /nt4
  • %System%\cmd.exe /c sed.efix -r "s/hex/hex\(1\)/Ig ; s/SYSTEM/Software\EFix/Ig" .\Temp\devices.1
  • %System%\cmd.exe /S /D /c" type .\Temp\devices.2"
  • grep.efix -qi "EFix"
  • swreg.efix import .\Temp\devices.2
  • %System%\cmd.exe /c swreg.efix query "hklm\software\EFix\mounteddevices" /s|grep.efix -i "dosdevices"|grep.efix -i "cdrom"|sed.efix "s/REG_SZ.*// ; s/\DosDevices\//I ; s/ *// ; s/\t// ; s/\://"
  • cmd.exe /c echo.
  • swreg.efix query "hklm\system\select" /v "current"
  • sed.efix "/\t/!d ; s/.*\t// ; s/ .*//"
  • grep.efix -i "Desktop" .\Temp\CF.1
  • sed.efix "s/\\/\/g"
  • grep.efix -i "Startup" .\Temp\CF.1
  • sed "s/\\/\/g"
  • sed.efix -e "s/\\/\/g" .\Temp\CF.2
  • grep.efix -i "cache="
  • grep.efix -i "Common Startup" .\Temp\SF.1
  • swreg.efix query "hklm\software\EFix\mounteddevices" /s
  • grep.efix -i "dosdevices"
  • grep.efix -i "cdrom"
  • sed.efix "s/REG_SZ.*// ; s/\DosDevices\//I ; s/ *// ; s/\t// ; s/\://"

It creates the following folders:

  • %System Root%\NEFix\Program
  • %System Root%\NEFix
  • %System Root%\NEFix\Tools
  • %System Root%\NEFix\Dat
  • %System Root%\NEFix\Backup
  • %System Root%\NEFix\Temp

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

Other System Modifications

This Hacking Tool adds the following registry keys:

HKEY_CURRENT_USER\Software\WinRAR SFX

HKEY_LOCAL_MACHINE\software\EFix

HKEY_LOCAL_MACHINE\Software\EFix\
mounteddevices

It adds the following registry entries:

HKEY_CURRENT_USER\Software\WinRAR SFX
C%%NEFix = "%System Root%\NEFix"

HKEY_LOCAL_MACHINE\SOFTWARE\EFix
(Default) = ""

HKEY_LOCAL_MACHINE\SOFTWARE\EFix
Desktop = "%Desktop%"

HKEY_LOCAL_MACHINE\SOFTWARE\EFix
Startup = "%User Startup%"

HKEY_LOCAL_MACHINE\SOFTWARE\EFix
cache = "%Temporary Internet Files%"

HKEY_LOCAL_MACHINE\SOFTWARE\EFix
Common Startup = "%All Users Profile%\Microsoft\Windows\Start Menu\Programs\Startup"

HKEY_LOCAL_MACHINE\SOFTWARE\EFix
Temp = "%SystemRoot%\TEMP"

HKEY_LOCAL_MACHINE\SOFTWARE\EFix
Tmp = "%SystemRoot%\TEMP"

HKEY_LOCAL_MACHINE\SOFTWARE\EFix\
mounteddevices\??
Volume{b9b10144-b2c7-11e6-9a80-806e6f6e6963} = "\xee\xbc\x9d\xeb\xbe\x81"

HKEY_LOCAL_MACHINE\SOFTWARE\EFix\
mounteddevices\??
Volume{b9b10145-b2c7-11e6-9a80-806e6f6e6963} = "\xee\xbe\xb5\xeb\xbe\x81"

HKEY_LOCAL_MACHINE\SOFTWARE\EFix\
mounteddevices\??
Volume{b9b10148-b2c7-11e6-9a80-806e6f6e6963} = "{random characters}"

HKEY_LOCAL_MACHINE\SOFTWARE\EFix\
mounteddevices
#{f41a9f97-b2c7-11e6-bcb3-08002751c1fb} = "\xee\xbc\x9d\xeb\xbe\x81"

HKEY_LOCAL_MACHINE\SOFTWARE\EFix\
mounteddevices\??
Volume{f41a9f9a-b2c7-11e6-bcb3-08002751c1fb} = "\xee\xbc\x9d\xeb\xbe\x81"

Dropping Routine

This Hacking Tool drops the following files:

  • %System Root%\NEFix\Program\list.bat
  • %System Root%\NEFix\Temp\SF.1
  • %System Root%\NEFix\Program\filelist.bat
  • %System Root%\NEFix\Dat\Run.dat
  • %System Root%\NEFix\Dat\CLSID.dat
  • %System Root%\NEFix\errlog.txt
  • %System Root%\NEFix\Program\save.bat
  • %System Root%\NEFix\Dat\IFEO.dat
  • %System Root%\NEFix\Temp\nircheck.1
  • %System Root%\NEFix\Temp\temp1.2
  • %System Root%\NEFix\Temp\Fixreg.1
  • %System Root%\NEFix\Temp\CF.1
  • %System Root%\NEFix\Temp\tmp1.2
  • %System Root%\NEFix\main.bat
  • %System Root%\NEFix\Temp\devices.1
  • %System Root%\NEFix\Temp\temp1.1
  • %System Root%\NEFix\sed.EFix
  • %System Root%\NEFix\Program\noend.bat
  • %System Root%\NEFix\Dat\disk.dat
  • %System Root%\NEFix\swreg.EFix
  • %System Root%\NEFix\CProcess.EFix
  • %System Root%\NEFix\Fixreg.EFix
  • %System Root%\NEFix\Tools\Autorun.reg
  • %System Root%\NEFix\Temp\devices.2
  • %System Root%\NEFix\grep.EFix
  • %System Root%\NEFix\Program\delreg.bat
  • %System Root%\NEFix\Dat\listrun.dat
  • %System Root%\NEFix\Temp\EFix.1
  • %System Root%\NEFix\Temp\Iecache.1
  • %System Root%\NEFix\Dat\Service.dat
  • %System Root%\NEFix\Program\lang.bat
  • %System Root%\NEFix\Program\setting.bat
  • %System Root%\NEFix\more.com
  • %System Root%\NEFix\Dat\Fix.dat
  • %System Root%\NEFix\Program\del-df.bat
  • %System Root%\NEFix\nircmd.EFix
  • %System Root%\NEFix\Dat\notify.dat
  • %System Root%\NEFix\Program\PF.bat
  • %System Root%\NEFix\Temp\cprocess.1
  • %System Root%\NEFix\Temp\CF.2
  • %System Root%\NEFix\Temp\CDROM.1
  • %System Root%\NEFix\Program\check.bat

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 HackTool.Win32.NIRCMD.AB

[ 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 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
    • WinRAR SFX
  • In HKEY_LOCAL_MACHINE\software
    • EFix
  • In HKEY_LOCAL_MACHINE\Software\EFix
    • mounteddevices

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\WinRAR SFX
    • C%%NEFix = "%System Root%\NEFix"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\EFix
    • (Default) = ""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\EFix
    • Desktop = "%Desktop%"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\EFix
    • Startup = "%User Startup%"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\EFix
    • cache = "%Temporary Internet Files%"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\EFix
    • Common Startup = "%All Users Profile%\Microsoft\Windows\Start Menu\Programs\Startup"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\EFix
    • Temp = "%SystemRoot%\TEMP"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\EFix
    • Tmp = "%SystemRoot%\TEMP"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\EFix\mounteddevices\??
    • Volume{b9b10144-b2c7-11e6-9a80-806e6f6e6963} = "\xee\xbc\x9d\xeb\xbe\x81"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\EFix\mounteddevices\??
    • Volume{b9b10145-b2c7-11e6-9a80-806e6f6e6963} = "\xee\xbe\xb5\xeb\xbe\x81"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\EFix\mounteddevices\??
    • Volume{b9b10148-b2c7-11e6-9a80-806e6f6e6963} = "{random characters}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\EFix\mounteddevices
    • #{f41a9f97-b2c7-11e6-bcb3-08002751c1fb} = "\xee\xbc\x9d\xeb\xbe\x81"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\EFix\mounteddevices\??
    • Volume{f41a9f9a-b2c7-11e6-bcb3-08002751c1fb} = "\xee\xbc\x9d\xeb\xbe\x81"

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.
  • %System Root%\NEFix\Program\list.bat
  • %System Root%\NEFix\Temp\SF.1
  • %System Root%\NEFix\Program\filelist.bat
  • %System Root%\NEFix\Dat\Run.dat
  • %System Root%\NEFix\Dat\CLSID.dat
  • %System Root%\NEFix\errlog.txt
  • %System Root%\NEFix\Program\save.bat
  • %System Root%\NEFix\Dat\IFEO.dat
  • %System Root%\NEFix\Temp\nircheck.1
  • %System Root%\NEFix\Temp\temp1.2
  • %System Root%\NEFix\Temp\Fixreg.1
  • %System Root%\NEFix\Temp\CF.1
  • %System Root%\NEFix\Temp\tmp1.2
  • %System Root%\NEFix\main.bat
  • %System Root%\NEFix\Temp\devices.1
  • %System Root%\NEFix\Temp\temp1.1
  • %System Root%\NEFix\sed.EFix
  • %System Root%\NEFix\Program\noend.bat
  • %System Root%\NEFix\Dat\disk.dat
  • %System Root%\NEFix\swreg.EFix
  • %System Root%\NEFix\CProcess.EFix
  • %System Root%\NEFix\Fixreg.EFix
  • %System Root%\NEFix\Tools\Autorun.reg
  • %System Root%\NEFix\Temp\devices.2
  • %System Root%\NEFix\grep.EFix
  • %System Root%\NEFix\Program\delreg.bat
  • %System Root%\NEFix\Dat\listrun.dat
  • %System Root%\NEFix\Temp\EFix.1
  • %System Root%\NEFix\Temp\Iecache.1
  • %System Root%\NEFix\Dat\Service.dat
  • %System Root%\NEFix\Program\lang.bat
  • %System Root%\NEFix\Program\setting.bat
  • %System Root%\NEFix\more.com
  • %System Root%\NEFix\Dat\Fix.dat
  • %System Root%\NEFix\Program\del-df.bat
  • %System Root%\NEFix\nircmd.EFix
  • %System Root%\NEFix\Dat\notify.dat
  • %System Root%\NEFix\Program\PF.bat
  • %System Root%\NEFix\Temp\cprocess.1
  • %System Root%\NEFix\Temp\CF.2
  • %System Root%\NEFix\Temp\CDROM.1
  • %System Root%\NEFix\Program\check.bat

Step 6

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.
  • %System Root%\NEFix\Program
  • %System Root%\NEFix
  • %System Root%\NEFix\Tools
  • %System Root%\NEFix\Dat
  • %System Root%\NEFix\Backup
  • %System Root%\NEFix\Temp

Step 7

Scan your computer with your Trend Micro product to delete files detected as HackTool.Win32.NIRCMD.AB. 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:


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