Microsoft security software detects this threat.

This threat can send malicious data to your PC and corrupt some driver files, making them unusable..

See the Win32/Alureon family description for more information.

Find out ways that malware can get on your PC.

What to do now

Use the following free Microsoft software to detect this threat:

You should also run a full scan. A full scan might find other, hidden malware. 

Advanced troubleshooting

To restore your PC, you might need to download and run Windows Defender Offline. See our advanced troubleshooting page for more help.

Protect your sensitive information

This threat tries to steal your sensitive and confidential information. If you think your information has been stolen, see:

You should change your passwords after you've removed this threat:

Get more help

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

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

Threat behavior

Virus:Win32/Alureon.A is a detection for system drivers infected by members of the Win32/Alureon family.
Virus:Win32/Alureon.A is the detection for a system driver that has been infected by members of the Win32/Alureon family. In the wild, the following Alureon trojans have been observed to infect files, which are then detected as Virus:Win32/Alureon.A:
When the infecting trojan is run, it infects a system driver, usually 'atapi.sys'. It has also been observed to infect 'iastor.sys' but other system drivers may also be targeted.
Hides files and disk sectors
The system driver detected as Virus:Win32/Alureon.A is infected by the addition of code, whose function is to load a part of the Alureon rootkit. The Alureon rootkit is a component that gives Alureon the ability to avoid detection; it is created by the same Alureon trojan that infects the system driver.
The rootkit loaded by Virus:Win32/Alureon.A has the ability to avoid behavior blockers, which allows it to perform its malicious routines uninterrupted. It can also hide files and disk sectors.
Additional Iiformation
The rootkit loaded by Virus:Win32/Alureon.A has the ability to update its files through other Alureon configuration files, such as Trojan:Win32/Alureon.CT or Trojan:Win32/Alureon.gen!R.
Analysis by Patrik Vicol


Alerts from your security software might be the only symptom.


Alert level: Severe
First detected by definition:
Latest detected by definition: 1.173.2181.0 and higher
First detected on: Oct 23, 2009
This entry was first published on: Dec 02, 2009
This entry was updated on: Dec 30, 2014

This threat is also detected as:
  • Win32/Olmarik!generic (CA)
  • Rootkit.Win32.TDSS.u (Kaspersky)
  • W32/TDSS.drv.gen4.A (Norman)
  • Mal/TDSSPack-V (Sophos)