Thursday, April 21, 2005

New variant of the Mitglieder Trojan being mass mailed -

PandaLabs has detected the mass mailing of spam that contains the new and dangerous CG variant of the Mitglieder Trojan (also known as Bagle.bn by other security companies). Data collected by the international PandaLabs network shows that this new malicious code is starting to spread rapidly across several countries.

The email messages in which this new Trojan has been detected have a blank subject and message body and include an attached file called work.zip. However, users should be careful, as this Trojan is being spammed out manually or through zombi computers and therefore, the characteristics of the email message carrying Mitglieder.CG could be totally different.

If the user runs the file containing Mitglieder.CG, the Notepad application will be opened, displaying the word 'Sorry'. At the same time, a file called winshost.exe is created in the Windows system directory on the affected computer. When the computer restarts, this file will be run and create another file called wiwhost.exe. This file will modify the host file so that the user will not be able to access certain websites; mainly websites related to antivirus programs and IT security.

In addition, the Trojan deletes files and Registry entries and stops processes related to security applications that could be installed on the computer.

According to Luis Corrons: "the aim of Mitglieder.CG is to download malware to the computer. It does this by connecting to a large number of Internet addresses and trying to download files, which could predictably contain other malware, such as backdoors, spyware, adware, bots, etc. This allows the authors of these malicious code to create networks of infected computers in order to launch attacks on other computers or collect hundreds of thousands of email address to send spam to."

Due to the wide circulation of this Trojan, Panda Software advises users to take precautions and to update their antivirus software. Panda Software has made the corresponding updates available to its clients to detect and disinfect this new malicious code.