This Ransomware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It drops files as ransom note. It avoids encrypting files with the following file extensions.
Arrival Details
This Ransomware 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 Ransomware adds the following processes:
- if --safe-mode commandline parameter is used:
- "%System%\bcdedit.exe" /set {default} safeboot network
- "%System%\shutdown.exe" -r
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)
Autostart Technique
This Ransomware 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\ControlSet001\
Control\SafeBoot\Network\
nokonoko → if --safe-mode commandline parameter is used.
Other System Modifications
This Ransomware modifies the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\SafeBoot\Network\
nokonoko → if --safe-mode commandline parameter is used.
(Default) = Service
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control → if --safe-mode commandline parameter is used.
ServicesPipeTimeout = 86400000
Other Details
This Ransomware does the following:
- It encrypts files found in the following drives:
- Fixed Drives
- Removable Drives
- Remote (Network) Drives
- The following can be changed in the runtime configuration:
- Directories to avoid
- File extensions to avoid
- Ransom note content
- Ransom note filename
- Appended extension of encrypted files
The following can be enabled/disabled in the runtime configuration:- Encryption of network shares
- Delete shadow copies
- Loading of hidden drives
It accepts the following parameters:
- --config → {Base64 encoded config} → runtime configuration of the sample
- --dir → encrypt selected directories and sub-directories
- --file → encrypt selected files
- --safe-mode → reboots and encrypts the user's machine in safe mode
- --debug
- --verbose
Ransomware Routine
This Ransomware avoids encrypting files found in the following folders:
- windows
- program files
- program files (X86)
- appdata
- programdata
- system volume information
It appends the following extension to the file name of the encrypted files:
It drops the following file(s) as ransom note:
- {Encrypted Directory}\NOKONOKO-readme.html
It avoids encrypting files with the following file extensions:
Step 1
Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:
- TROJ.Win32.TRX.XXPE50FFF069
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
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To restart in Safe Mode:
• For Windows 7 and Windows Server 2008 (R2) users
- Restart your computer.
- Press F8 after the Power-On Self Test (POST) routine is done. If the Advanced Boot Options menu does not appear, try restarting and then pressing F8 several times after the POST screen is displayed.
- On the Advanced Boot Options menu, use the arrow keys to select the Safe Mode option, and then press Enter.
• For Windows 8, Windows 8.1, and Windows Server 2012 users
- Access the Charms bar by moving your mouse pointer to the upper right corner of the screen.
- Move your mouse pointer down and click Settings>Change your PC Settings.
- In the left panel, click General.
- In the right panel, scroll down to the bottom to find the Advanced startup section, then click the Restart now button and wait for the system to restart.
- In the Advanced Startup menu, click Troubleshoot>Advanced Options>Startup Settings>Restart and wait for the system to restart.
- In the Startup Settings menu, press 4 to enable safe mode.
• For Windows 10 users
- Press Windows logo key + I on your keyboard to open Settings. If that doesn't work, select the Start button, then select Settings.
- Select Update & Security > Recovery.
- Under Advanced startup, select Restart now.
- After your PC restarts to the Choose an option screen, select Troubleshoot > Advcanced options > Startup settings > Restart.
- After your PC restarts, you'll see a list og options. Select 4 or press F4 to start your PC in Safe Mode.
Step 5
Restore this modified 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_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\SafeBoot\Network\nokonoko
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control
- ServicesPipeTimeout = 86400000
To restore the registry value this malware/grayware modified:
- Open Registry Editor.
» For Windows 7 and Server 2008 (R2) users, click the Start button, type regedit in the Search input field then press Enter.
» For Windows 8, 8.1, 10, and 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, double-click the following:
HKEY_LOCAL_MACHINE>SYSTEM>ControlSet001>Control>SafeBoot>Network>nokonoko - In the right panel, locate the registry value:
(Default) = Service - In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SYSTEM>ControlSet001>Control - In the right panel, locate the registry value:
ServicesPipeTimeout = 86400000 - Close Registry Editor.
Step 6
Delete this registry key
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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_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\SafeBoot\Network\nokonoko
To delete registry keys this malware/grayware created:
- Open Registry Editor. To do this:
» For Windows 7 and Server 2008 (R2) users, click the Start button, type regedit in the Search input field then press Enter.
» For Windows 8, 8.1, 10, and 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. HKEY_LOCAL_MACHINE>SYSTEM>ControlSet001>Control>SafeBoot>Network>nokonoko - Close Registry Editor.
Step 7
Search and delete these files
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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.
- {Encrypted Directory}\NOKONOKO-readme.html
To delete malware/grayware files:
For Windows 7 and Server 2008 (R2), 8, 8.1, 10, and 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 users, right-click on the lower left corner of the screen, then click File Explorer.
- In the Search Computer/This PC input box, type:
- {Encrypted Directory}\NOKONOKO-readme.html
- Once located, select the file then press SHIFT+DELETE to delete it.
- Repeat the said steps for all files listed.
*Note: Read the following Microsoft page if these steps do not work on Windows 7 and Server 2008 (R2).
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.Win32.NOKO.YPDFA. 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.
Step 9
Restore encrypted files from backup.
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