Is ur PC Virus infected ???
Boot your system in Safemode
Go to command prompt, in Drive C do the following commands.
Type -> ATTRIB -H -R -S AUTORUN.INF then press enter
Type -> DEL AUTORUN.INF then press enter
Type -> ATTRIB -H -R -S Recycled then press enter
In Windows Explorer in Safemode, remove the folder Recycled in drive C use Shift-Delete to delete the folder.
Repeat Step 3 to 6 for all drives of your system including the USB drive.
Search for CTFMON.EXE in your system using the Search of Windows found in Start Menu. If you find a file that is not located in C:\WINDOWS\SYSTEM32, delete it immediately. Dont forget to empty the recycle bin afterwards (Usually the virus will copy itself in the Startup folder of the Startmenu. Check if the file is present there and delete it then.)
To disable autorun of drives (i.e. everytime you double-click a drive or cd or usb, it is auto open) follow the following step:
Click Start->Run->type REGEDIT.EXE
Go to this key from the register HKEY_CURRENT_USER\Software\ Microsoft\Windows\CurrentVersion\Policies\Explorer
Look for the entry NoDriveTypeAutoRun, double click the entry
Type a new value : 0FF (Hex) for the NoDriveTypeAutoRun, this will turn off the AutoRun for all drives, and press ENTER
Reboot the system.
Viruses that uses Autorun.INF
There are several viruses that uses the autorun.inf to spread itself such as the Bacalid (hides itself in ctfmon.exe) and the RavMon.EXE. These viruses set its file attributes to System+Hidden+Read-Only attributes so some anti-viruses will have a hard time detecting or finding them. These viruses save itself in the root directory of every available drives of the current infected computer and runs itself every time you Double-Click the drive. In USB Sticks and CDs that are infected by the virus runs automatically especially if drive autorun is enabled for the current drives (which is usually by default, autorun for drives are enabled).
Disable AUTORUN from Registry
Now you can disable the AUTORUN for all drives by configuring the registry. Open the registry by typing regedit.exe to the command prompt (if your still at the command prompt) or execute it in Run. Look for the HKEY_CURRENT_USER\Software\ Microsoft\Windows\CurrentVersion\Policies\Explorer as shown below:
Double-click the NoDriveAutorun DWORD entry and type the value HEX: FF (255 in Decimal). (If the NoDriveAutorun does not exists, you can creat it by right-clicking the right side area of the regedit window, then click New->DWord Value -> type NoDriveAutorun) Close the registry and restart the computer. This procedure will disable all the autorun for all drives of your computer and at least will prevent the autorun function of infected USB drives or CDs and avoid the infection of viruses like the Bacalid and RavMon.exe
If you want to prevent viruses that uses autorun.inf to infect your USB flash drive, try to do this:
1. Open your flash drive via Command Prompt (do this via Start->Run->cmd.exe)
2. Change your logged drive to your USB flash drive (e.g. if your drive is at drive E: then type E: on the command prompt then press enter)
3. Create a folder named: AUTORUN.INF on the root directory of your flash drive. (to do this type the command: MD\AUTORUN.INF). If an error: a subdirectory already exists… shows, try to follow the instruction above to remove existing autorun.inf before doing this instruction.
The reason why this will avoid future infection is that autorun.inf viruses usually generates a file autorun.inf. Having an AUTORUN.INF folder on the root directory of your drives will make virus programs unable to create their own autorun.inf file, virus can’t even overwrite it because it’s a folder and not a file…
Go to command prompt, in Drive C do the following commands.
Type -> ATTRIB -H -R -S AUTORUN.INF then press enter
Type -> DEL AUTORUN.INF then press enter
Type -> ATTRIB -H -R -S Recycled then press enter
In Windows Explorer in Safemode, remove the folder Recycled in drive C use Shift-Delete to delete the folder.
Repeat Step 3 to 6 for all drives of your system including the USB drive.
Search for CTFMON.EXE in your system using the Search of Windows found in Start Menu. If you find a file that is not located in C:\WINDOWS\SYSTEM32, delete it immediately. Dont forget to empty the recycle bin afterwards (Usually the virus will copy itself in the Startup folder of the Startmenu. Check if the file is present there and delete it then.)
To disable autorun of drives (i.e. everytime you double-click a drive or cd or usb, it is auto open) follow the following step:
Click Start->Run->type REGEDIT.EXE
Go to this key from the register HKEY_CURRENT_USER\Software\ Microsoft\Windows\CurrentVersion\Policies\Explorer
Look for the entry NoDriveTypeAutoRun, double click the entry
Type a new value : 0FF (Hex) for the NoDriveTypeAutoRun, this will turn off the AutoRun for all drives, and press ENTER
Reboot the system.
Viruses that uses Autorun.INF
There are several viruses that uses the autorun.inf to spread itself such as the Bacalid (hides itself in ctfmon.exe) and the RavMon.EXE. These viruses set its file attributes to System+Hidden+Read-Only attributes so some anti-viruses will have a hard time detecting or finding them. These viruses save itself in the root directory of every available drives of the current infected computer and runs itself every time you Double-Click the drive. In USB Sticks and CDs that are infected by the virus runs automatically especially if drive autorun is enabled for the current drives (which is usually by default, autorun for drives are enabled).
Disable AUTORUN from Registry
Now you can disable the AUTORUN for all drives by configuring the registry. Open the registry by typing regedit.exe to the command prompt (if your still at the command prompt) or execute it in Run. Look for the HKEY_CURRENT_USER\Software\ Microsoft\Windows\CurrentVersion\Policies\Explorer as shown below:
Double-click the NoDriveAutorun DWORD entry and type the value HEX: FF (255 in Decimal). (If the NoDriveAutorun does not exists, you can creat it by right-clicking the right side area of the regedit window, then click New->DWord Value -> type NoDriveAutorun) Close the registry and restart the computer. This procedure will disable all the autorun for all drives of your computer and at least will prevent the autorun function of infected USB drives or CDs and avoid the infection of viruses like the Bacalid and RavMon.exe
If you want to prevent viruses that uses autorun.inf to infect your USB flash drive, try to do this:
1. Open your flash drive via Command Prompt (do this via Start->Run->cmd.exe)
2. Change your logged drive to your USB flash drive (e.g. if your drive is at drive E: then type E: on the command prompt then press enter)
3. Create a folder named: AUTORUN.INF on the root directory of your flash drive. (to do this type the command: MD\AUTORUN.INF). If an error: a subdirectory already exists… shows, try to follow the instruction above to remove existing autorun.inf before doing this instruction.
The reason why this will avoid future infection is that autorun.inf viruses usually generates a file autorun.inf. Having an AUTORUN.INF folder on the root directory of your drives will make virus programs unable to create their own autorun.inf file, virus can’t even overwrite it because it’s a folder and not a file…
posted by Nilesh at
September 26, 2008
0 Comments
