Arrival Details
This Worm 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 files:
- %System%\{eight random characters}.dll -> detected as WORM_AUTORUN.TA
- %System%\del.bat - script responsible for the deletion of initially executed copy of the malware
- {All drives}\autorun.inf
(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:
- %System%\{eight random characters}.exe
- {All drives}\auto.exe
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)
It injects codes into the following process(es):
Autostart Technique
This Worm adds and runs the following services:
- Service Name: {eight random characters}
Display Name: {eight random characters}
Start Type: SERVICE_AUTO_START
Binary Pathname: %%System%\{eight random characters}.exe
Other System Modifications
This Worm adds the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{eight random characters}
Enum =
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{eight random characters
Security =
It adds the following registry entries:
KEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{eight random characters}\Enum
0 = "Root\LEGACY_{eight random characters}\0000"
KEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{eight random characters}\Enum
Count = "1"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{eight random characters}\Enum
Next Instance = "1"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{eight random characters}\Security
Security = {value}
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\
SHOWALL
CheckedValue = "0"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
PCHealth\ErrorReporting
DoReport = "0"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
PCHealth\ErrorReporting
ShowUI = "0"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT
ReportBootOk = "1"
Propagation
The said .INF file contains the following strings:
[AutoRun]
open=auto.exe
shellexecute=auto.exe
shell\Auto\command=auto.exe
Download Routine
This Worm downloads an updated copy of itself from the following website(s):
- http://nx.{BLOCKED}b.cn/soft//update.txt
As of this writing, the said sites are inaccessible.
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
Restart in Safe Mode
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To restart in Safe Mode:
• For Windows 2000 users
- Restart your computer.
- Press F8 when you see the Starting Windows bar at the bottom of the screen.
- Choose the Safe Mode option from the Windows Advanced Options menu then press Enter.
• For Windows XP users
- Restart your computer.
- Press F8 after the Power-On Self Test (POST) routine is done. If the Windows Advanced Options menu does not appear, try restarting then pressing F8 several times when the POST screen appears.
- Choose the Safe Mode option from the Windows Advanced Options menu then press Enter.
• For Windows Server 2003 users
- Restart your computer.
- Press F8 after Windows starts up. If the Windows Advanced Options menu does not appear, try restarting again and pressing F8 several times afterward.
- On the Windows Advanced Option menu, use the arrow keys to select Safe Mode then press Enter.
• For Windows Vista, Windows 7, and Windows Server 2008 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.
Step 4
Disable this malware service
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-
- {eight random characters}
Disabling a Malware Service
To disable a service:
- Open a command prompt window:
» For Windows 2000, Windows XP, and Windows Server 2003 users, click Start>Run, type cmd in the text box provided, and press Enter.
» For Windows Vista, Windows 7, and Windows 2008 users, click the Start button, type cmd in the Search input field, and press Enter.
» For Windows 8, Windows 8.1, and Windows Server 2012 users, right-click on the lower left corner of the screen, click Command Prompt. - At the command prompt, type the following:
NET STOP - {eight random characters}
- Press Enter. A message should indicate that the service has been stopped successfully.
- Close the command prompt window.
Step 5
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\CurrentControlSet\Services
- {eight random characters}
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>CurrentControlSet>Services - Still in the left panel, locate and delete the key:
{eight random characters} - Close Registry Editor.
Step 6
Restore these modified registry values
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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\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\SHOWALL
- From: CheckedValue = "0"
To: CheckedValue = "1"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PCHealth\ErrorReporting
- From: DoReport = "0"
To: DoReport = "{User Preference}"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PCHealth\ErrorReporting
- From: ShowUI = "0"
To: ShowUI = "{User Preference}"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT
- From: ReportBootOk = "1"
To: ReportBootOk = "{User Preference}"
To restore registry values this malware/grayware modified:
- Open Registry Editor. To do this:
- On Windows 2000, XP, and Server 2003:
Click Start>Run, type REGEDIT in the text box provided, and then press Enter. - On Windows Vista, 7, and Server 2008:
Click the Start button, type REGEDIT in the Search input field then press Enter. - On Windows 8, 8.1, and Server 2012:
Right-click on the lower left corner of the screen and click Run, type REGEDIT in the Run input field, and then press Enter.
- In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows>CurrentVersion>Explorer>Advanced>Folder>Hidden>SHOWALL - In the right panel, locate the registry value:
CheckedValue = "0" - Right-click on the value name and choose Modify. Change the value data of this entry to:
CheckedValue = "1" - In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>PCHealth>ErrorReporting - In the right panel, locate the registry value:
DoReport = "0" - Right-click on the value name and choose Modify. Change the value data of this entry to:
DoReport = "{User Preference}" - Again In the right panel, locate the registry value:
ShowUI = "0" - Right-click on the value name and choose Modify. Change the value data of this entry to:
ShowUI = "{User Preference}" - In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT - In the right panel, locate the registry value:
ReportBootOk = "1" - Right-click on the value name and choose Modify. Change the value data of this entry to:
ReportBootOk = "{User Preference}" - 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.
- %System%\{eight random characters}.dll
- %System%\del.bat
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
- %System%\{eight random characters}.dll
- %System%\del.bat
- 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:
- %System%\{eight random characters}.dll
- %System%\del.bat
- 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 8
Search and delete AUTORUN.INF files created by WORM.WIN32.KAXELA.AA that contain these strings
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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:
DATA_GENERIC
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:
DATA_GENERIC - 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 9
Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM.WIN32.KAXELA.AA. 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.
