The BKA Trojan still spreading through emails containing fake invoices

Even though the fraudsters behind the BKA Trojan (aka Ransom Trojan) have been caught by the police, there are still a lot of emails spreading the Trojan in circulation.

One of these emails drew my attention because it was addressed directly to me and because of the way in which it is constructed.


The email pretends to come from the well-known online shopping portal and it is addressed to only the recipient in the From field.

It contains in the body the first and last name taken probably from the email address, thus being very convincing for the unaware user. The same formula is used to name the attachment – a zip archive with the name “Rechnung <first name> <last name>.zip” / “Invoice <first name> <last name>.zip”.

What is really interesting, inside the ZIP archive there is another ZIP archive called “Bestellung 16.02.2013 – Rechnung” / “Order 16.02.2003 – Invoice” containing a .com file. However, a brief analysis shows that this is just a normal executable created with Visual Studio containing the trojan ’TR/Ransom.Foreign.acdb.1′. This method of packing the malware is very clever, because very few security solutions on gateways and most certainly no local solution, scans on more than one layer recursively inside archives. Using this technique the cybercriminals ensured that the payload goes through the security checks on its route to the user’s inbox.

Avira users don’t have to worry about this, all products detect this file as ’TR/Ransom.Foreign.acdb.1′.


Sorin Mustaca

IT Security Expert

via Avira – TechBlog

© Copyright Sorin Mustaca, All rights Reserved. Written For: Sorin Mustaca on Cybersecurity

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About the Author

Sorin Mustaca
Sorin Mustaca, (ISC)2 CSSLP, CompTIA Security+ and Project+, is working since over 20 years in the IT Security industry and worked between 2003-2014 for Avira as Product Manager for the known products used by over 100 million users world-wide. Today he is CEO and owner of Endpoint Cybersecurity GmbH focusing on Cybersecurity, secure software development and security for IoT and Automotive. He is also running his personal blog Sorin Mustaca on Cybersecurity and is the author of the free eBook Improve your security .

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