Thorough tests show that Backdoor.Pihar will infect Master Boot Record of the computer and leads to the instability of Windows operation.

Backdoor.Pihar is a Trojan that may infect master boot record (MBR) of the target computer. Symantec and other anti-virus applications may detect the compromised MBR as Boot.Pihar. To allow remote unauthorized access, Backdoor.Pihar will open a backdoor and accepts commands from an attacker.

Damage Level: Medium

Systems Affected: Windows 9x, 2000, XP, Windows Vista, Windows 7

When running inside the computer, Backdoor.Pihar creates a couple of random files using random hexadecimal characters. It also modifies various registry entries to lessen Internet browser’s security settings.

To run itself on Windows start-up, Backdoor.Pihar will add a registry entry that calls the Trojan during boot-up. Additionally, it will inject malicious code to master boot record (MBR) to achieve similar objective. The infected master boot record can be identified as Boot.Pihar.

Lastly, this Trojan will communicate to predefined web site address and accept remote commands through backdoor. It may contact any of the following web sites.


The Trojan may arrive on a computer in a number of schemes and that may include the following:

  • Integrate a comment containing malicious links to unmanaged web sites and forums. The link aims to point user to a web site hosting the Trojan.
  • It sends anonymous messages or postings to social networking sites. Again, the post includes a link to send user to a compromised web address.
  • Malicious code is planted on pages of legitimate web sites that unexpectedly download the Trojan to visitor’s computer. This technique uses an SQL injection to attack any sites with known security vulnerability.
  • Lastly, attackers behind Backdoor.Pihar use an unsecured file-sharing network to spread a copy of itself that are usually embedded on shareware applications. Downloading and executing the free program silently installs the Trojan without user’s notice.

How to Remove Backdoor.Pihar

1. Temporarily Disable System Restore (Windows Me/XP). [how to]
2. To be able to identify even the most recent variant of Backdoor.Pihar, open your antivirus application and update the virus definition file.

3. Start Windows in Safe Mode with Networking.
- From a power-off state, turn on the computer and press F8 on your keyboard repeatedly.
- Your computer will display Windows Advanced Boot Options menu. Please select Safe Mode with Networking.
- The system will now boot Windows and loads only necessary drivers and files.

4. Open your antivirus program and run a full system scan. After the scan, delete all infected items. If unable to delete, better place them in quarantine. Once the scan is complete, please proceed with the next step.

Scan with Norton Power Eraser:

Additional virus removal tool like Norton Power Eraser provides deep scanning technology to eliminate other threats not detected by a normal virus scan. Use this tool with extra caution.

5. Go to this link and download Norton Power Eraser.
6. Once the download completes, double click on the file NPE.exe to run the program.
7. It will prompt for End User License Agreement, click on Accept to continue.
8. On NPE main window, click on Scan. Then select Exclude Rootkit Scan. Click on Continue to proceed.
9. Virus scanning may take some time. After running the scan, NPE will display the scan result.

Important! If there are any detected threats under Suspicious, remove the check mark. Only threats in Detected category are necessary to remove at this point. Make sure that you mark the Create System Restore Point before proceeding with the fix.

10. Now click on Fix to start removing the threats including Backdoor.Pihar remnants if there are any.
11. When done, Norton Power Eraser will restart the computer. Then after a reboot, it will initialize and display the eliminated threats.
12. You may now close Norton Power Eraser.

Alternative Removal Method for Backdoor.Pihar

Option 1 : Use Windows System Restore to return Windows to previous state

If Backdoor.Pihar enters the computer, there is a big chance that Windows files, registry entries and other essential components are also infected. System Restore can reinstate clean system files by restoring the configuration to an earlier date. The method also replaces compromised files with a clean version. If you have a saved restore point before Backdoor.Pihar infiltrates the PC, we highly encourage you to execute this procedure if none of the above works. You may proceed with Windows System Restore, click here to see the full procedure.

Option 2 : Backdoor.Pihar manual uninstall guide

IMPORTANT! Manual removal of Backdoor.Pihar requires technical skills. Deleting system files and registry entries by mistake may result to total disability of Windows system. We advise you to perform a backup of registry before proceeding with this guide.

1. Kill any running process that belongs to Backdoor.Pihar.
- Press Ctrl+Alt+Del on your keyboard.
- When Windows Task Manager appears, look for Backdoor.Pihar files (refer to Technical Reference) and click End Process.

End Task

2. Delete all registry entries that belong to this malware.
- Press [Windows Key]+R on your keyboard.
- In the 'Open' dialog box, type regedit and press Enter. This will open registry editor.
- Find and delete registry entries as mentioned in Technical Reference section below.
- Close registry editor. Changes made will be save automatically.

Run Regedit

3. Scan the computer with antivirus program.
- Connect to Internet and open your antivirus software. Please update to obtain the latest database and necessary files.
- Restart the computer in Safe Mode.
- Just before Windows logo begins to load press F8 on your keyboard.
- On Windows Advanced Boot Options, select Safe Mode and press Enter.

4. Delete all files dropped by Backdoor.Pihar.
- While still in Safe Mode, search and delete malicious files. Please refer to 'Technical Reference'. Make sure that you execute 'End Task' first before deleting the file. Otherwise, the system will not let you perform this action.

Associated Files and Folders:Added Registry Entries:

2 Responses

  1. says: hase a new virusfree owner
    greets and thanks

  2. mary says:

    how would i get rid of this in windows 7

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