Brazilian Masquerade

What do you see here?

A free AV product protecting a Windows XP machine, right?

No, actually its malware a Brazilian Trojan banker coming via
email and then using a masquerade to stay in the system. The malware
is 386Kb only, written in Delphi, and comes via an email together
with a bunch of many other malicious and non-malicious files.

If the victim clicks on the system tray icon, he will get this
message:

(Translation: Your Avast! Antivirus is
being updated, wait.)

In some combinations it also shows messages like this one:

(Translation: Avast! antivirus:
Attention, your system is protected)

Why do cybercriminals use such a method to hide their malware in
the system? Google trends shows that Avast is the most popular AV in
Brazil. And my experience of life in Latin America shows that people
still dont want to pay when there is something free.

Before dropping the mentioned fake Avast product, another module,
based on the anti-rootkit product Avenger, tries to remove the
following legitimate AV products from the system if they are
installed: AVG, McAfee, Panda, Nod32, Kaspersky, Bitdefender,
Norton, Microsoft Security Essentials, PSafe, Avira and Avast.

There are many malicious files used in the same campaign. They have
different roles and are detected by Kaspersky Anti-virus as Trojan.Win32.Delf.ddir,
Trojan.Win32.ChePro.aov, Trojan.Win32.ChePro.anv, Trojan-Banker.Win32.Delf.apg,
not-a-virus:RiskTool.Win32.Deleter.i, Trojan-Banker.Win32.Agent.jst
and Trojan.Win32.Delf.ddiq

Looks like cybercriminals from Brazil think this way: "Why to
fight AV detections? Sometimes it's too complicated. Let's just
better replace them with our own fake solutions and everybody gets
happy
".

Last, but not least, in addition to malware related to the mentioned
campaign, we see more and more Trojan Bankers from Brazil coming
with fake descriptions, pretending to be modules of different AV
products. Heres one example:

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