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 component file(s):
- %Temp%\key8854321.pub
- %Windows%\inf\averbh_noav.pnf
- %Windows%\hdv_725x.sys -> normal file
(Note: %Temp% is the Windows temporary folder, where it usually is C:\Windows\Temp on all Windows operating system versions.. %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)
It drops the following copies of itself into the affected system:
- %System%\MaintenaceSrv32.exe - 32 bit system
- %System%\MaintenaceSrv64.exe - 64 bit system
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)
Propagation
This Worm drops copies of itself in the following shared folders:
- ADMIN$
- C$\WINDOWS
- D$\WINDOWS
- E$\WINDOWS
Dropping Routine
This Worm drops the following files:
- %System%\{wiper name} ← used to overwrite the disk
where {wiper name} is any of the following:
- _tdibth.exe
- _wialx002.exe
- acpipmi2z.exe
- af0038bdax.exe
- arcx6u0.exe
- averfix2h826d_noaverir.exe
- hidirkbdmvs2.exe
- mdamx_5560.exe
- mdmgcs_8.exe
- mdmusrk1g5.exe
- megasasop.exe
- netbxndxlg2.exe
- prncaz90x.exe
- prngt6_4.exe
- prnlx00ctl.exe
- prnsv0_56.exe
- tsprint_ibv.exe
- vsmxraid.exe
- wiacnt7001.exe
- %System%\{network communicator name} -> Used to connect to its C&C server
where the {network communicator name} can be any of the following:- netnbdrve.exe
- prnod802.exe
- netrndiscnt.exe
- netrtl42l.exe
- mdmadccnt.exe
- prnca00.exe
- bth2bht_ibv32.exe
- cxfalcon_ibL32.exe
- mdmsupr30.exe
- digitalmediadevicectl.exe
- mdmetech2dmv.exe
- netb57vxx.exe
- winwsdprint.exe
- prnkwy005.exe
- composite005.exe
- mdmar1_ibv32.exe
- prnle444.exe
- kscaptur_ibv32.exe
- mdmzyxlga.exe
- usbvideob.exe
- input_ibv48.exe
- prnok002_ibv.exe
- averfx2swtvZ.exe
- wpdmtp_ibv32.exe
- mdmti_ibv32.exe
- printupg_ibv32.exe
- wiabr788.exe
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)
It executes the dropped file. As a result, malicious routines of the dropped file are exhibited on the affected system.
Other Details
This Worm adds and runs the following services:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\MaintenaceSrv
Start = 2
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\MaintenaceSrv
ImagePath = "{drop copy} LocalService" or "{malware path and filename} LocalService"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\MaintenaceSrv
DisplayName = "Maintenace Host Service"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\MaintenaceSrv
DependOnService = "RpcSs"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\MaintenaceSrv
ObjectName = "LocalSystem"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\MaintenaceSrv
Description = "The Maintenace Host service is hosted in the LSA process. The service provides key process isolation to private keys and associated cryptographic operations as required by the Common Criteria. The service stores and uses long-lived keys in a secure process compl0"
It does the following:
- It loads %Windows%\hdv_725x.sys as a kernel driver
- Service Name: hdv_725x
- Service Type: Kernel
- ImagePath: \??\%Windows%\hdv_725x.sys
- It overwrites the first sector (200 bytes) of the MBR, ultimate destroying its boot up procedure in the process.
- There is no C&C configured for this variant, even though it has a component that is used specifically to connect to its C&C server.
- This variant also overwrites its own files in the process.
- It overwrites files found in the following directory:
- C:\Users\desktop
- C:\Users\download
- C:\Users\document
- C:\Users\picture
- C:\Users\video
- C:\Users\music
- C:\Windows\System32\Drivers
- C:\Windows\System32\Config\systemprofile
- It forces the machine to shutdown, after overwriting the MBR and the files.
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)
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
Restore your system's Master Boot Record (MBR)
To restore your system's Master Boot Record (MBR):
• On Windows 2000, XP, and Server 2003:
- Insert your Windows Installation CD into your CD drive then restart your computer.
- When prompted, press any key to boot from the CD.
- On the Main Menu, type r to enter the Recovery Console.
(Note for Windows 2000: After pressing r, type c to choose the Recovery Console on the repair options screen.) - Type the number that corresponds to the drive and folder that contains Windows (usually C:\WINDOWS) and press Enter.
- Type your Administrator password and press Enter.
- In the input box, type the following then press Enter:
fixmbr {affected drive} - Type exit and press Enter to restart the system normally.
• On Windows Vista, 7, and Server 2008:
- Insert your Windows Installation DVD into the DVD drive, then press the restart button on your computer.
- When prompted, press any key to boot from the DVD.
- Depending on your Windows Installation DVD, you might be required to choose the installation language. On the Install Windows window, choose your language, locale, and keyboard layout or input method. 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 menu, click Command Prompt.
- In the Command Prompt window, type the following then press Enter:
BootRec.exe /fixmbr - Type exit and press Enter to close the Command Prompt window.
- Click Restart to restart your computer normally.
• On Windows 8, 8.1, and Server 2012:
- 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 - Type exit and press Enter to close the Command Prompt window.
- Click Continue to restart the system normally.
Step 4
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 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
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:
MaintenaceSrv - Close Registry Editor.
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.
- %Temp%\key8854321.pub
- %Windows%\inf\averbh_noav.pnf
- %Windows%\hdv_725x.sys
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:
- %Temp%\key8854321.pub
- %Windows%\inf\averbh_noav.pnf
- %Windows%\hdv_725x.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.
*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:
- %Temp%\key8854321.pub
- %Windows%\inf\averbh_noav.pnf
- %Windows%\hdv_725x.sys
- 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 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJAN.WIN32.DISTTRACK.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.
Step 8
Restore encrypted files from backup.
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