Trojan:Win32/Sefnit.AU

The Trojan:Win32/Sefnit.AU Trojan is one of the many Trojans that are involved in malware attacks by the SEFNIT family of malware. The Trojan:Win32/Sefnit.AU, a variant of this family may act as a Trojan downloader or installer, establishing the initial backdoor on the victim's computer and establishing an unauthorized connection with a remote server and downloading other threats and other members of the Trojan:Win32/Sefnit.AU family, such as Trojan:Win32/Sefnit.AT and Trojan:Win32/Sefnit.gen!D, which carry out other variants in this attack. Trojan:Win32/Sefnit.AU takes advantage of social engineering scams carried out through file sharing networks, in particular the eMule file sharing application. Other Trojan:Win32/Sefnit.AU distribution methods include social engineering, the installation of several threats and PUPs and spam email messages.

How Trojan:Win32/Sefnit.AU is Acquired

Trojan:Win32/Sefnit.AU and other threats in this family of Trojans may be bundled with legitimate programs downloaded from poorly guarded sources. There are various unsafe executable files that are disguised as other installers but that install the Trojan:Win32/Sefnit.AU instead. Some examples include the following:

• FlashPlayerUpdateService.exe.
• BleServicesCtrl.exe.
• Wins.exe.
• TrustedInstaller.exe.

All of the above are names of legitimate Windows services that have been co-opted by the Trojan:Win32/Sefnit.AU infection to carry out its attack and conceal its true nature. The Trojan:Win32/Sefnit.AU infection is usually part of click fraud schemes that generate revenue at the expense of the computer user. Some Trojan:Win32/Sefnit.AU variants may establish a proxy service (that is from a legitimate source) named 3proxy.

Trojan:Win32/Sefnit.AU Payload is Meant to Cause More Problems

The main purpose of Trojan:Win32/Sefnit.AU is to download other threats. Trojan:Win32/Sefnit.AU establishes an unauthorized connection with its Command and Control servers to download the other threats. Trojan:Win32/Sefnit.AU may establish both HTTP and security connections and, in the case of some variants, may even use Tor to establish its connection. As mentioned above, the main purpose of malware in the Sefnit family is to carry out click fraud. This means that Trojan:Win32/Sefnit.AU uses the victim's computer to click on affiliate marketing links and advertisements in order to generate advertisement and affiliate marketing revenue. One of the reasons why Trojan:Win32/Sefnit.AU uses 3proxy is to make it seems as if various different computers are clicking on the same link.