This worm arrives by connecting affected removable drives to a system. It 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 an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
It deletes the initially executed copy of itself.
Arrival Details
This worm arrives by connecting affected removable drives to a system.
It 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 worm drops the following copies of itself into the affected system and executes them:
- %Windows%\system\dllcache.exe
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)
It drops the following component file(s):
- %System%\drivers\sysdrv32.sys
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)
Autostart Technique
This worm adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
netmon = "%Windows%\system\dllcache.exe"
It adds the following entries to allow itself to run on safe mode:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\SafeBoot\Minimal\
dllcache
(Default) = "Service"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\SafeBoot\Network\
dllcache
(Default) = "Service"
It registers its dropped component as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\sysdrv32
DisplayName = "Play Port I/O Driver"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\sysdrv32
ImagePath = "\??\%System%\drivers\sysdrv32.sys"
Propagation
This worm drops the following copy(ies) of itself in all removable drives:
- {Removable Drive Letter}:\strongkey-rc1.3-build-208.exe
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
The said .INF file contains the following strings:
[autorun]
shellexecute=strongkey-rc1.3-build-208.exe
action=Open folder to view files
shell\default=Open
shell\default\command=strongkey-rc1.3-build-208.exe
shell=default
Other Details
This worm connects to the following possibly malicious URL:
It deletes the initially executed copy of itself
Step 1
Before doing any scans, Windows XP, Windows Vista, and Windows 7 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 delete files detected as WORM_NEERIS.MS using either the Startup Disk or Recovery Console
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To identify and delete the malware/grayware file:
• On Windows XP and Server 2003 systems:
- Scan your computer with your Trend Micro product and then take note of the names of the malware/grayware files detected.
- Click Start>Run. In the Open input box, type secpol.msc and press Enter.
- In the left panel, double-click Local Policies>Security Options.
- In the right panel, double-click Recovery Console: Allow floppy copy and access to all drives and folders.
- Select Enabled and click OK.
- Insert the Windows Installation CD into the CD drive, then restart your computer.
- When prompted, press any key to boot from the CD.
- On the main menu, type r to go to the Recovery Console.
- Type the number that corresponds to the drive and directory that contains Windows (usually C:\WINDOWS) and press Enter.
- Type the Administrator password and press Enter.
- In the input box, type the following then press Enter:
SET AllowAllPaths = TRUE
del "{malware/grayware path and file name}" - Type exit and press Enter to restart the system normally.
• On Windows Vista, 7, and Server 2008 systems:
- Scan your computer with your Trend Micro product and then take note of the names of the malware/grayware files detected.
- Insert your Windows Installation DVD in the DVD drive, then Press the restart button.
- When prompted, press any key to boot from the CD.
- Depending on your Windows Installation DVD, you might be required to select the installation language. Then on the Install Windows window, choose your language, locale, and keyboard layout or input method. Click Next, then click Repair your computer.
- Select Use recovery tools that can help fix problems starting Windows. Select your installation of Windows. Click Next.
- If the Startup Repair window appears, click Cancel, Yes, then Finish.
- In the System Recovery Options window, click Command Prompt.
- In the Command Prompt window, type the following then press Enter:
BootRec.exe /fixmbr
del "{malware/grayware path and file name}" - Type exit and press Enter to close the Command Prompt window.
- Click Restart to restart the system normally.
• On Windows 8, 8.1, and Server 2012 systems:
- Scan your computer with your Trend Micro product and then take note of the names of the malware/grayware files detected.
- Insert your Windows Installation DVD in the DVD drive, then restart your computer.
- When prompted, press any key to boot from the DVD.
- Depending on your Windows Installation DVD, you might be required to select the keyboard layout. Then on the Windows Setup window, choose your language, locale, and input method. Click Next, then click Repair your computer.
- Click Troubleshoot>Advanced Options>Command Prompt.
- In the Command Prompt window, type the following then press Enter:
BootRec.exe /fixmbr
del "{malware/grayware path and file name}" - Type exit and press Enter to close the Command Prompt window.
- Click Continue to restart the system normally.
Step 4
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\Services
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\SafeBoot\Minimal
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\SafeBoot\Network
To delete the registry key this malware/grayware created:
- Open Registry Editor.
» For Windows 2000, Windows XP, and Windows Server 2003 users, click Start>Run, type regedit in the text box provided, and then press Enter.
» For Windows Vista, Windows 7, and Windows Server 2008 users, click the Start button, type regedit in the Search input field then press Enter.
» For Windows 8, Windows 8.1, and Windows Server 2012 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>Services - Still in the left panel, locate and delete the key:
sysdrv32 - In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SYSTEM>ControlSet001>Control>SafeBoot>Minimal - Still in the left panel, locate and delete the key:
dllcache - In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SYSTEM>ControlSet001>Control>SafeBoot>Network - Still in the left panel, locate and delete the key:
dllcache - Close Registry Editor.
Step 5
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- netmon = "%Windows%\system\dllcache.exe"
To delete the registry value this malware created:
- Open Registry Editor. To do this:
» For Windows 2000, Windows XP, and Windows Server 2003 users, click Start>Run, type regedit in the text box provided, and then press Enter.
» For Windows Vista, Windows 7, and Windows Server 2008 users, click the Start button, type regedit in the Search input field then press Enter.
» For Windows 8, Windows 8.1, and Windows Server 2012 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_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows>CurrentVersion>Run - In the right panel, locate and delete the entry:
netmon = "%Windows%\system\dllcache.exe" - Close Registry Editor.
Step 6
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.
- %Windows%\system\dllcache.exe
- %System%\drivers\sysdrv32.sys
To delete malware/grayware files:
For Windows 2000, Windows XP, and Windows Server 2003:
- Right-click Start then click Search....
- In the File name* input box, type
- %Windows%\system\dllcache.exe
- %System%\drivers\sysdrv32.sys
- In the Look In drop-down list, select My Computer then press Enter.
- Once located, select the file then press SHIFT+DELETE to delete it.
- Repeat the said steps for all files listed.
*Note: The file name input box title varies depending on the Windows version (e.g. Search for files or folders named or All or part of the file name.).
For Windows Vista, Windows 7, Windows Server 2008, Windows 8, Windows 8.1, and Windows Server 2012:
- Open a Windows Explorer window.
- For Windows Vista, 7, and Server 2008 users, click Start>Computer.
- For Windows 8, 8.1, 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:
- %Windows%\system\dllcache.exe
- %System%\drivers\sysdrv32.sys
- 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.
Step 7
Search and delete AUTORUN.INF files created by WORM_NEERIS.MS that contain these strings
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- [autorun]
- shellexecute=strongkey-rc1.3-build-208.exe
- action=Open folder to view files
- shell\default=Open
- shell\default\command=strongkey-rc1.3-build-208.exe
- shell=default
To identify and delete AUTORUN.INF files created:
For Windows 2000, Windows XP, and Windows Server 2003:
- Right-click the Start button then choose Search... or Find..., depending on the version of Windows you are running.
- In the File name* input box, type:
AUTORUN.INF - In the Look in: drop-down list, select a drive, then press Enter.
- Select the file, then open using Notepad.
- Check if the following lines are present in the file:
- [autorun]
- shellexecute=strongkey-rc1.3-build-208.exe
- action=Open folder to view files
- shell\default=Open
- shell\default\command=strongkey-rc1.3-build-208.exe
- shell=default
- If the lines are present, delete the file.
- Repeat steps 3 to 6 for the remaining AUTORUN.INF files in other remaining removable drives.
- Close Search Results.
*Note: The file name input box title varies depending on the Windows version (e.g.
Search for files or folders named or
All or part of the file name.).
For Windows Vista, Windows 7, Windows Server 2003, Windows 8, Windows 8.1, and Windows Server 2012:
- Open a Windows Explorer window.
- For Windows Vista, 7, and Server 2008 users, click Start>Computer.
- For Windows 8, 8.1, 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:
AUTORUN.INF - Select the file, then open using Notepad.
- Check if the following lines are present in the file:
- [autorun]
- shellexecute=strongkey-rc1.3-build-208.exe
- action=Open folder to view files
- shell\default=Open
- shell\default\command=strongkey-rc1.3-build-208.exe
- shell=default
- If the lines are present, delete the file.
- Repeat steps 3 to 5 for the remaining AUTORUN.INF files in other remaining removable drives.
- Close Search Results.
Step 8
Scan your computer with your Trend Micro product to clean files detected as WORM_NEERIS.MS. 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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