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Trojan:DOS/Alureon.A


Microsoft security software detects and removes this threat.

This threat is part of the Alureon malware family. It runs a file installed by other Alureon malware.

Find out ways that malware can get on your PC.



What to do now

The following free Microsoft software detects this threat:

However, in some cases you might need to use the free tool Windows Defender Offline to fully clean your PC:

The following articles might help if you're having trouble getting the tool to work:

After you've used Windows Defender Offline, you should make sure your security software is up to date and run a full scan:

Even if we've already detected and removed this particular threat, running a full scan might find other malware that is hiding on your PC.

You can also visit the Microsoft virus and malware community or our advanced troubleshooting page for more help.

If you’re using Windows XP, see our Windows XP end of support page.

Additional recovery instructions

Repair your Master Boot Record - run the Bootrec.exe tool

To completely remove this threat you might need to run the Bootrec.exe tool using Windows installation media.

You can read more about the Bootrec.exe tool in the Use Bootrec.exe in the Windows RE article.

Before you begin:

You will need to use Windows installation media to run the Bootrec.exe tool. If you don’t have Windows installation
media, you might have to create it.

To run the Bootrec.exe tool in Windows 8:

  1. Put your Windows 8 media in the DVD or USB drive and restart your PC.
  2. Select a language, time and currency, and keyboard or input method, and then click Next.
  3. Click Repair your computer.
  4. Click Troubleshoot, then Advanced options.
  5. Click Command Prompt and then type Bootrec /FixMBR and then press Enter.
  6. Type Exit and the press Enter.
  7. At the Choose an Option screen click Continue.
  8. Remove the Windows 8 media from your drive and restart your PC.

To run the Bootrec.exe tool in Windows 7:

  1. Put your Windows 7 media in the DVD or USB drive and restart your PC.
  2. Press any key when you are prompted.
  3. Select a language, time and currency, and keyboard or input method, and then click Next.
  4. Click Repair your computer.
  5. Select the operating system that you want to repair, and then click Next.
  6. In the SystemRecovery Options dialog box, click Command Prompt.
  7. Type Bootrec.exe / FixMBR, and then press Enter.
  8. Remove the Windows 7 media from your drive and restart your PC.

Threat behavior

Trojan:DOS/Alureon.A is a member of the Alureon malware family. It tries to decrypt and run the contents of a file named ldr16.

The file is stored on the encrypted virtual file system (VFS) created by Trojan:Win32/Alureon.DX.

Analysis by Scott Molenkamp


Symptoms

Alerts from your security software may be the only symptom.


Prevention


Alert level: Severe
First detected by definition: 1.87.1229.0
Latest detected by definition: 1.173.2181.0 and higher
First detected on: Aug 04, 2010
This entry was first published on: Aug 27, 2010
This entry was updated on: Dec 30, 2014

This threat is also detected as:
No known aliases