Modified by: Kiyoshi Obuchi
 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan 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: 14,469,712 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 12 Jun 2019

Arrival Details

This Trojan 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 drops the following copies of itself into the affected system:

  • %System Root%\Program Files\Gramblr\gramblr.exe

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

It adds the following processes:

  • %System Root%\Program Files\Gramblr\gramblr.exe
  • %System%\svchost.exe -k WerSvcGroup
  • %System%\WerFault.exe -u -p 2348 -s 472
  • %System%\WerFault.exe -u -p 1564 -s 600
  • "%System%\wermgr.exe" "-queuereporting_svc" "%All Users Profile%\Microsoft\Windows\WER\ReportQueue\AppCrash_gramblr.exe_0a0f923e19e3df513a5daa733d1dba2a08ac90_cab_0b3f9cd7"

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). )

It creates the following folders:

  • %All Users Profile%\Microsoft\Windows\WER\ReportQueue\AppCrash_gramblr.exe_0a0f923e19e3df513a5daa733d1dba2a08ac90_cab_0b3f9cd7
  • %All Users Profile%\Gramblr
  • %System Root%\Program Files\Gramblr

(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). . %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

Autostart Technique

This Trojan registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\gramblrclient
DisplayName = "Windows Connectivity Manager for Gramblr"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\gramblrclient
ImagePath = "%System Root%\Program Files\Gramblr\gramblr.exe"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\gramblrclient
Start = "SERVICE_AUTO_START"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Gramblr

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Gramblr
DisplayIcon = "%System Root%\Program Files\Gramblr\gramblr.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Gramblr
DisplayName = "Gramblr"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Gramblr
DisplayVersion = "2.9.188"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Gramblr
InstallLocation = "%System Root%\Program Files\Gramblr"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Gramblr
Language = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Gramblr
NoModify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Gramblr
NoRepair = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Gramblr
Publisher = "Gramblr Team"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Gramblr
UninstallString = "%System Root%\Program Files\Gramblr\gramblr.exe --uninstall"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Gramblr
VersionMajor = "2"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Gramblr
VersionMinor = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Gramblr
EstimatedSize = "6800"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Gramblr
UrlInfoAbout = "http://{BLOCKED}r.com"

Dropping Routine

This Trojan drops the following files:

  • %Windows%\Temp\etilqs_2xSnNHJSXW4EqRh
  • %All Users Profile%\Gramblr\gramblr.db
  • %Windows%\Temp\WERF730.tmp.WERInternalMetadata.xml
  • %Windows%\Temp\etilqs_eKjXeJ1OOgjXbkz
  • %Windows%\Temp\etilqs_X1TafUakdYMWeaz
  • %Windows%\Temp\etilqs_QCBYaru3QmjUCsE
  • %Windows%\Temp\etilqs_l7rte0sbP6juHoq
  • %All Users Profile%\Microsoft\Windows\WER\ReportQueue\AppCrash_gramblr.exe_0a0f923e19e3df513a5daa733d1dba2a08ac90_cab_0b3f9cd7\WERF750.tmp.hdmp
  • %Windows%\Temp\WER849.tmp.mdmp
  • %User Temp%\etilqs_CubLD2VJDUmcCMX
  • %User Temp%\etilqs_6FkRHLpbIqXuO2h
  • %User Temp%\etilqs_NWMgW0SQSNjjM2w
  • %All Users Profile%\Gramblr\gramblr.db-journal
  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\Gramblr.lnk
  • %Windows%\Temp\WERF750.tmp.hdmp
  • %Windows%\Temp\WERF750.tmp
  • %Windows%\Temp\WERF730.tmp
  • %All Users Profile%\Gramblr\sessions.db-journal
  • %All Users Profile%\Microsoft\Windows\WER\ReportQueue\AppCrash_gramblr.exe_0a0f923e19e3df513a5daa733d1dba2a08ac90_cab_0b3f9cd7\Report.wer
  • %All Users Profile%\Microsoft\Windows\WER\ReportQueue\AppCrash_gramblr.exe_0a0f923e19e3df513a5daa733d1dba2a08ac90_cab_0b3f9cd7\WER849.tmp.mdmp
  • %All Users Profile%\Microsoft\Windows\WER\ReportQueue\AppCrash_gramblr.exe_0a0f923e19e3df513a5daa733d1dba2a08ac90_cab_0b3f9cd7\WERF730.tmp.WERInternalMetadata.xml
  • %Windows%\Temp\WERF450.tmp
  • %All Users Profile%\Microsoft\Windows\WER\ReportQueue\AppCrash_gramblr.exe_0a0f923e19e3df513a5daa733d1dba2a08ac90_cab_0b3f9cd7\Report.wer.tmp
  • %All Users Profile%\Gramblr\sessions.db
  • %Windows%\Temp\WERF450.tmp.appcompat.txt
  • %Windows%\Temp\etilqs_Up5CiGbJdTd2iN0
  • %Windows%\Temp\WER849.tmp
  • %All Users Profile%\Microsoft\Windows\WER\ReportQueue\AppCrash_gramblr.exe_0a0f923e19e3df513a5daa733d1dba2a08ac90_cab_0b3f9cd7\WERF450.tmp.appcompat.txt
  • %All Users Profile%\Gramblr\runtime.log

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData 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).)

  SOLUTION

Minimum Scan Engine: 9.850
SSAPI PATTERN File: 2.183.00
SSAPI PATTERN Date: 13 Jun 2019

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 PUA.Win64.Gramblr.A

[ 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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
    • Gramblr

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Gramblr
    • DisplayIcon = "%System Root%\Program Files\Gramblr\gramblr.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Gramblr
    • DisplayName = "Gramblr"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Gramblr
    • DisplayVersion = "2.9.188"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Gramblr
    • InstallLocation = "%System Root%\Program Files\Gramblr"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Gramblr
    • Language = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Gramblr
    • NoModify = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Gramblr
    • NoRepair = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Gramblr
    • Publisher = "Gramblr Team"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Gramblr
    • UninstallString = "%System Root%\Program Files\Gramblr\gramblr.exe --uninstall"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Gramblr
    • VersionMajor = "2"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Gramblr
    • VersionMinor = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Gramblr
    • EstimatedSize = "6800"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Gramblr
    • UrlInfoAbout = "http://{BLOCKED}r.com"

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.
  • %Windows%\Temp\etilqs_2xSnNHJSXW4EqRh
  • %All Users Profile%\Gramblr\gramblr.db
  • %Windows%\Temp\WERF730.tmp.WERInternalMetadata.xml
  • %Windows%\Temp\etilqs_eKjXeJ1OOgjXbkz
  • %Windows%\Temp\etilqs_X1TafUakdYMWeaz
  • %Windows%\Temp\etilqs_QCBYaru3QmjUCsE
  • %Windows%\Temp\etilqs_l7rte0sbP6juHoq
  • %All Users Profile%\Microsoft\Windows\WER\ReportQueue\AppCrash_gramblr.exe_0a0f923e19e3df513a5daa733d1dba2a08ac90_cab_0b3f9cd7\WERF750.tmp.hdmp
  • %Windows%\Temp\WER849.tmp.mdmp
  • %User Temp%\etilqs_CubLD2VJDUmcCMX
  • %User Temp%\etilqs_6FkRHLpbIqXuO2h
  • %User Temp%\etilqs_NWMgW0SQSNjjM2w
  • %All Users Profile%\Gramblr\gramblr.db-journal
  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\Gramblr.lnk
  • %Windows%\Temp\WERF750.tmp.hdmp
  • %Windows%\Temp\WERF750.tmp
  • %Windows%\Temp\WERF730.tmp
  • %All Users Profile%\Gramblr\sessions.db-journal
  • %All Users Profile%\Microsoft\Windows\WER\ReportQueue\AppCrash_gramblr.exe_0a0f923e19e3df513a5daa733d1dba2a08ac90_cab_0b3f9cd7\Report.wer
  • %All Users Profile%\Microsoft\Windows\WER\ReportQueue\AppCrash_gramblr.exe_0a0f923e19e3df513a5daa733d1dba2a08ac90_cab_0b3f9cd7\WER849.tmp.mdmp
  • %All Users Profile%\Microsoft\Windows\WER\ReportQueue\AppCrash_gramblr.exe_0a0f923e19e3df513a5daa733d1dba2a08ac90_cab_0b3f9cd7\WERF730.tmp.WERInternalMetadata.xml
  • %Windows%\Temp\WERF450.tmp
  • %All Users Profile%\Microsoft\Windows\WER\ReportQueue\AppCrash_gramblr.exe_0a0f923e19e3df513a5daa733d1dba2a08ac90_cab_0b3f9cd7\Report.wer.tmp
  • %All Users Profile%\Gramblr\sessions.db
  • %Windows%\Temp\WERF450.tmp.appcompat.txt
  • %Windows%\Temp\etilqs_Up5CiGbJdTd2iN0
  • %Windows%\Temp\WER849.tmp
  • %All Users Profile%\Microsoft\Windows\WER\ReportQueue\AppCrash_gramblr.exe_0a0f923e19e3df513a5daa733d1dba2a08ac90_cab_0b3f9cd7\WERF450.tmp.appcompat.txt
  • %All Users Profile%\Gramblr\runtime.log

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.
  • %All Users Profile%\Microsoft\Windows\WER\ReportQueue\AppCrash_gramblr.exe_0a0f923e19e3df513a5daa733d1dba2a08ac90_cab_0b3f9cd7
  • %All Users Profile%\Gramblr
  • %System Root%\Program Files\Gramblr

Step 7

Scan your computer with your Trend Micro product to delete files detected as PUA.Win64.Gramblr.A. 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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