Cybercriminals take advantage of the popularity of the Zoom messaging app. This backdoor is found in a fake Zoom installer. This is probably hosted on malicious or suspicious sites.
This Backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.
Arrival Details
This Backdoor 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 Backdoor drops the following files:
- %User Temp%\pyclient.cmd → Detected as Backdoor.BAT.DEVILSHADOW.THEAABO
- %User Temp%\cmd_shell.exe → Detected as Trojan.Win32.DEVILSHADOW.THEAABO
- %User Profile%\boot-startup.vbs → Detected as Trojan.BAT.DEVILSHADOW.THEAABO
- %User Profile%\new_script.txt → Detected as Trojan.JS.DEVILSHADOW.THEAABO
- %User Profile%\shell.bat → Detected as Trojan.BAT.DEVILSHADOW.THEAABO
- %User Temp%\zoom.exe → Legitimate Zoom Installer
- %User Profile%\node.exe → Legitimate node.exe
- %System Root%\botnet\client_id_file → contains generated_id
- %System Root%\botnet\bot_id_{Generated ID} {Hostname} {IP Address} {Client} → Client Identifier
- %System Root%\botnet\botnet_start.vbs
- %System Root%\botnet\wget.js
- %System Root%\botnet\pyclient.cmd → Copy of the one in %User Temp%
- %System Root%\botnet\scexec-win32.exe
- %System Root%\botnet\scexec-win64.exe
- %System Root%\botnet\Rar.exe
- %System Root%\botnet\K7firewall.exe
- %System Root%\botnet\unzip.exe
- %System Root%\botnet\webcam.exe
- %System Root%\botnet\execute.vbs
- %User Temp%\av → contains result of Anti-Virus Query
It adds the following processes:
- %System%\cmd.exe /c %User Temp%\pyclient.cmd
- %System%\cmd.exe /c %User Temp%\cmd_shell.exe
- %System%\cmd.exe /c %User Temp%\zoom.exe
- %System%\cmd.exe /c cd %userprofile% & attrib +s +h +a *.vbs & attrib +s +h +a *.bat & reg add Hkey_CURRENT_USER\software\microsoft\windows\currentversion\run /v bootstartup /t reg_sz /d %userprofile%\boot-startup.vbs /f & shell.bat
- %System%\cmd.exe /c "Tasklist /FI WINDOWTITLE eq D3ViL ShaDow"
- %System%\cmd.exe /c "Tasklist /FI WINDOWTITLE eq Administrator: D3ViL ShaDow"
- %System%\cmd.exe attrib +s +h +a %System Root%\botnet
- %System%\cmd.exe copy /y %User Temp%\pyclient.cmd %System Root%\botnet\pyclient.cmd
- %System%\cmd.exe reg add hkcu\software\microsoft\windows\currentversion\run /v botnet /t reg_sz /d C:\botnet\botnet_start.vbs /f
- %System%\cmd.exe ping www.google.com -n 1
- %System&\cmd.exe unzip.exe -ox python_client.zip
- %System%\cmd.exe %System%\WScript.exe %System Root%\botnet\botnet_start.vbs
- %System%\cmd.exe copy /y %System%\cmd.exe %Public%\explorer.exe
- %System%\cmd.exe %User Profile%\node.exe new_script.txt
- %Public%\explorer.exe
- %System&\cmd.exe wmic /namespace:\root\securitycemter2 path antivirusproduct GET displayName, productState, pathToSignedProductExe
It creates the following folders:
(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)
Autostart Technique
This Backdoor adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
bootstartup = %User Profile%\boot-startup.vbs
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
botnet = %System Root%\botnet\botnet_start.vbs
Backdoor Routine
This Backdoor executes the following commands from a remote malicious user:
- Update/Reset/Terminate Client (Self)
- Load Client Modules (Self)
- Log Keystrokes
- Take Screenshots
- Record Desktop
- Operate Webcam
- Operate CMD
- Install Programming Languages
- Download/Upload/Execute Files
- Install and Operate Ngrok
- Install and Operate WinVNC
- List and Modify AutoStart Registries
- List, Add and Start Scheduled Tasks
- Check and Elevate User Privileges
- Execute Shellcode and Scripts
- Harvest the Following Information:
- Process List
- Drive List
- Directories and Files List
- System Info
- Startup Items
- AntiVirus Info
- Locally Stored Credentials
It connects to the following websites to send and receive information:
- https://hosting303.{BLOCKED}hostapp.com
- madleets.{BLOCKED}s.net:4444
Download Routine
This Backdoor accesses the following websites to download files:
- https://raw.{BLOCKED}usercontent.com/DevilBot000/Tools/master/unzip.exe → %System Root%\botnet\unzip.exe
- https://raw.{BLOCKED}usercontent.com/DevilBot000/Tools/master/python_client.zip → %System Root%\botnet\python_client.zip
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
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 3
Identify and terminate files detected as Backdoor.Win32.DEVILSHADOW.THEAABO
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- 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.
- 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.
- If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.
To terminate the malware/grayware/spyware process:
- Scan your computer with your Trend Micro product and take note of the name of the malware/grayware/spyware detected.
- Open Windows Task Manager. To do this, press CTRL+SHIFT+ESC.
- View the list of all running programs. To do this:
• For Windows 7 and Server 2008 (R2) users, click the Processes tab.
• For Windows 8, 8.1, 10, and Server 2012 (R2) users, click the Details tab. - In the list of running programs, locate a malware/grayware/spyware file detected earlier.
- Select the detected files, then press either the End Task or the End Process button, depending on the version of Windows you are using.
- Do the same for the remaining detected malware/grayware/spyware files in the list of running programs.
- To check if the malware/grayware/spyware process has been terminated, close Task Manager, and then open it again.
- Close Task Manager.
Step 4
Delete this registry value
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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
- bootstartup = %User Profile%\boot-startup.vbs
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- botnet = %System Root%\botnet\botnet_start.vbs
To delete the registry value this malware created:
- Open Registry Editor. To do this:
» For Windows 7 and Windows Server 2008 (R2) users, click the Start button, type regedit in the Search input field then press Enter.
» For Windows 8, Windows 8.1, 10, and Windows Server 2012 (R2) users, right-click on the lower left corner of the screen, click Run, type regedit in the text box provided, and then press Enter. - In the left panel of the Registry Editor window, double-click the following:
HKEY_CURRENT_USER>Software>Microsoft>Windows>CurrentVersion>Run - In the right panel, locate and delete the entry:
bootstartup = %User Profile%\boot-startup.vbs - Again In the right panel, locate and delete the entry:
botnet = %System Root%\botnet\botnet_start.vbs - Close Registry Editor.
Step 5
Search and delete these folders
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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.
To delete malware/grayware/spyware folders:
For Windows 7, Windows Server 2008 (R2), Windows 8, Windows 8.1, Windows 10, and Windows Server 2012 (R2):
- Open a Windows Explorer window.
- For Windows 7 and Server 2008 (R2) users, click Start>Computer.
- For Windows 8, 8.1, 10, and Server 2012 (R2) users, right-click on the lower-left corner of the screen,then click File Explorer.
- In the Search Computer/This PC input box, type:
- Once located, select the file then press SHIFT+DELETE to permanently delete the folder.
- Repeat steps 2-3 for the remaining folders: *Note: Read the following Microsoft page if these steps do not work on Windows 7 and Server 2008 (R2).
Step 6
Search and delete this file
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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.
- %User Profile%\node.exe
- %System Root%\botnet\client_id_file
- %System Root%\botnet\bot_id_{Generated ID} {Hostname} {IP Address} {Client}%System Root%\botnet\botnet_start.vbs
- %System Root%\botnet\wget.js
- %System Root%\botnet\pyclient.cmd
- %System Root%\botnet\scexec-win32.exe
- %System Root%\botnet\scexec-win64.exe
- %System Root%\botnet\Rar.exe
- %System Root%\botnet\K7firewall.exe
- %System Root%\botnet\unzip.exe
- %System Root%\botnet\webcam.exe
- %System Root%\botnet\execute.vbs
To manually delete a malware/grayware file from an affected system:
•For Windows 7, Windows Server 2008 (R2), Windows 8, Windows 8.1, Windows 10, and Windows Server 2012 (R2):
- Open a Windows Explorer window.
- For Windows 7 and Server 2008 (R2) users, click Start>Computer.
- For Windows 8, 8.1, 10, and Server 2012 (R2) users, right-click on the lower-left corner of the screen,then click File Explorer.
- In the Search Computer/This PC input box, type:
- %User Profile%\node.exe
- %System Root%\botnet\client_id_file
- %System Root%\botnet\bot_id_{Generated ID} {Hostname} {IP Address} {Client}%System Root%\botnet\botnet_start.vbs
- %System Root%\botnet\wget.js
- %System Root%\botnet\pyclient.cmd
- %System Root%\botnet\scexec-win32.exe
- %System Root%\botnet\scexec-win64.exe
- %System Root%\botnet\Rar.exe
- %System Root%\botnet\K7firewall.exe
- %System Root%\botnet\unzip.exe
- %System Root%\botnet\webcam.exe
- %System Root%\botnet\execute.vbs
- Once located, select the file then press SHIFT+DELETE to delete it.
*Note: Read the following Microsoft page if these steps do not work on Windows 7 and Windows Server 2008 (R2).
Step 7
Scan your computer with your Trend Micro product to delete files detected as Backdoor.Win32.DEVILSHADOW.THEAABO. 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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