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 copies of itself into the affected system and executes them:
- %System%\{random filename 2}.exe
- %Application Data%\{random foldername}\{random filename}.exe
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
It drops the following files:
- %Windows%\Tasks\Security Center Update - {number}.job
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)
It creates the following folders:
- %Application Data%\{random foldername}
(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
Autostart Technique
This Trojan 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\CurrentControlSet\
Services\SecurityCenterServer{number}
ImagePath = "%System%\{random filename 2}.exe -service %Application Data%\{random foldername}\{random filename}.exe"
It adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{random entry} = "%Application Data%\{random folder name}\{random filename}.exe"
HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{random entry} = "%Application Data%\{random folder name}\{random filename}.exe"
Other System Modifications
This Trojan adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\PRQzDA
HKEY_LOCAL_MACHINE\SOFTWARE\{random key}
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SecurityCenterServer{number}
HKEY_CURRENT_USER\SOFTWARE\PRQzDA
HKEY_CURRENT_USER\SOFTWARE\{random key}
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\{random key}
License = "444"
HKEY_CURRENT_USER\SOFTWARE\{random key}
License = "444"
It deletes the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\SafeBoot
Other Details
This Trojan connects to the following possibly malicious URL:
- http://{BLOCKED}us.su/{url path}
- http://{BLOCKED}elow.su/{url path}
- http://{BLOCKED}black.su/{url path}
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
Scan your computer with your Trend Micro product and note files detected as TROJ_ZCLICK.YZYL
Step 4
Identify and delete files detected as TROJ_ZCLICK.YZYL using the Recovery Console
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To identify and delete of malware/grayware files:
• On Windows XP and Server 2003 systems:
- Insert your Windows Installation CD in your CD-rom.
- Press the restart button of your computer.
- When prompted, press any key to boot from the CD.
- When prompted on the Main Menu, type r to enter the recovery console.
(Note: On Windows 2000, after pressing r, type c to choose the Recovery Console in the repair options screen.) - When prompted, type your administrator password to log on.
- Once logged in, type the drive that contains Windows in the command prompt that appears, then press Enter.
- Type the drive that contains Windows, then press Enter.
- Type the following, then press Enter:
SET AllowAllPaths = TRUE
del {malware/grayware path and file name} - Repeat the above procedure for all files detected earlier.
- Type exit to restart the system.
• On Windows Vista, 7, and Server 2008 systems:
- 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 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}" - Repeat the above procedure for all files detected earlier.
- 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:
- 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}" - Repeat the above procedure for all files detected earlier.
- Type exit and press Enter to close the Command Prompt window.
- Click Continue to restart the system normally.
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\SOFTWARE
- In HKEY_LOCAL_MACHINE\SOFTWARE
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- SecurityCenterServer{number}
- In HKEY_CURRENT_USER\SOFTWARE
- In HKEY_CURRENT_USER\SOFTWARE
To delete registry keys this malware/grayware 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 - Still in the left panel, locate and delete the key:
PRQzDA - Again Still in the left panel, locate and delete the key:
{random key} - In the left panel of the Registry Editor window, double-click the following:
HKEY_LOCAL_MACHINE>SYSTEM>CurrentControlSet>Services - Still in the left panel, locate and delete the key:
SecurityCenterServer{number} - In the left panel of the Registry Editor window, double-click the following:
HKEY_CURRENT_USER>SOFTWARE - Still in the left panel, locate and delete the key:
PRQzDA - Again Still in the left panel, locate and delete the key:
{random key} - Close Registry Editor.
Step 6
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
- {random entry} = "%Application Data%\{random folder name}\{random filename}.exe"
- In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- {random entry} = "%Application Data%\{random folder name}\{random filename}.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:
{random entry} = "%Application Data%\{random folder name}\{random filename}.exe" - 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:
{random entry} = "%Application Data%\{random folder name}\{random filename}.exe" - Close Registry Editor.
Step 7
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.
- %Application Data%\{random foldername}
To delete malware/grayware/spyware folders:
For Windows 2000, Windows XP, and Windows Server 2003:
- Right-click Start then click Search... or Find..., depending on the version of Windows you are running.
- In the File name* input box, type:
- %Application Data%\{random foldername}
- In the Look In drop-down list, select My Computer, then press Enter.
- Once located, select the folder then press SHIFT+DELETE to permanently delete the folder.
- Repeat steps 2 to 4 for the remaining folders:
- %Application Data%\{random foldername}
*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:
- %Application Data%\{random foldername}
- Once located, select the file then press SHIFT+DELETE to permanently delete the folder.
- Repeat steps 2-3 for the remaining folders:
- %Application Data%\{random foldername}
*Note: Read the following Microsoft page if these steps do not work on Windows 7.
Step 8
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.
- %Windows%\Tasks\Security Center Update - {number}.job
To manually delete a malware/grayware file from an affected system:
• For Windows 2000, Windows XP, and Windows Server 2003:
- Right-click Start then click Search....
- In the File name* input box, type the following:
- %Windows%\Tasks\Security Center Update - {number}.job
- 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.
*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%\Tasks\Security Center Update - {number}.job
- 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.
Step 9
Scan your computer with your Trend Micro product to delete files detected as TROJ_ZCLICK.YZYL. 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 10
Restore this deleted registry key/value from backup
*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control
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