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Virus:Win32/Alureon.A


Virus:Win32/Alureon.A is a detection for system drivers infected by members of the Win32/Alureon family.


What to do now

The Win32/Alureon trojan may enable an attacker to transmit malicious data to the infected computer. Recovering from this situation may require measures beyond removing the trojan itself from the computer.
 
To detect and remove this threat and other malicious software that may be installed in your computer, run a full-system scan with an up-to-date antivirus product such as the following:
 
 
For more information on antivirus software, see http://www.microsoft.com/windows/antivirus-partners/.
Restoring Corrupted Files
In some instances, Alureon may modify certain driver files such that they become corrupted and unusable. These corrupted files that will NOT be restored by detecting and removing this threat. In order to restore functionality to the computer, the corrupted file must be restored from backup. Users are advised to boot into a recovery environment and manually replace the file with a clean copy.
Restoring DNS Settings
The Domain Name System (DNS) is used (among other things) to map domain names to IP addresses - that is, to map human-readable domain names to machine-readable IP addresses. When a user attempts to visit a particular URL, a browser will use DNS servers to find the correct IP address of the requested domain. When a user is directed to a malicious server that is not part of the authoritative Domain Name System, an attacker can provide incorrect IP addresses at their choice to map to particular domain names, thus directing the user to possibly bogus or malicious sites without the affected user's knowledge.
 
Win32/Alureon may modify DNS settings on the host computer, thus the following steps may be required after the Win32/Alureon removal is complete:
  • If the computer has a network interface that does not receive a configuration using DHCP, reset the DNS configuration if necessary. For information on configuring TCP/IP to use DNS in Windows XP, see http://support.microsoft.com/kb/305553
  • If a dial-up connection is sometimes used from the computer, reconfigure the dial-up settings in the rasphone.pbk file as necessary, as Win32/Alureon may set the fields "IpDnsAddress" and "IpDns2Address" in the rasphone.pbk file to the attacker's address. The Microsoft scanner code that automatically removes Win32/Alureon backs up the infected dial-up configuration file to:
    %ALLUSERSPROFILE%\Application Data\Microsoft\Network\Connections\Pbk\rasphone.pbk.bak

Threat behavior

Virus:Win32/Alureon.A is a detection for system drivers infected by members of the Win32/Alureon family.
Installation
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.
Payload
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 Information
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

Symptoms

There are no common symptoms associated with this threat. Alert notifications from installed antivirus software may be the only symptom(s).

Prevention


Alert level: Severe
First detected by definition: 1.69.77.0
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: Apr 17, 2011

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)