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Why the most successful Retefe spam campaign never paid off

Switzerland is one of the main targets of the Retefe banking trojan since its first appearance in November 2013. At that time, it changed the local DNS resolver on the computer (See also blog post “Retefe Bankentrojaner” in German only). Almost a year went by until they changed to the still current approach of setting a proxy auto-config (PAC) URL (See also blog post “The Retefe banking Trojan has targeted Switzerland“). To understand the story of this blog post, it helps to understand the modus operandi of the Retefe malware. We recommend you read up on it on our blog links posted above if you are not familiar with it.

While the Retefe actors are constantly changing tactics, for example their newest campaigns also target Mac OS X users, their malware still works the same. One of notable changes was the introduction of Tor in 2016. At first, they started using Tor gateway domain names such as onion.to, onion.link within the proxy auto-config URLs, later on they switched to Tor completely. The advantage of using Tor is of course, anonymity and the difficulty to block or take down the infrastructure.

Onion domain names don’t use DNS or do they?
The Tor network can use .onion domain names but these names are not resolved over DNS but instead work only in the Tor network. RFC 7686 (The “.onion” Special-Use Domain Name) goes into more details on the special case of .onion domain names. However, the fact is that .onion domain names do leak into the DNS system. For potential reasons and more information on this subject we recommend the paper by Versign Labs “Measuring the Leakage of Onion at the Root” (PDF).
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A new issue of our SWITCH Security Report is available!

Dear Reader!

A new issue of our monthly SWITCH Security Report is available!

The topics covered in this report are:

  • Cybercriminals increasingly targeting Mac users
  • Malware fitted as standard for Android
  • Switzerland breaks taboo of Net neutrality for sake of CHF 320 million
  • Internet of Things toys spying on children of all ages

The Security Report is available in both English and German.

»»  Download the english report.      »»  Download the german report.

Did you miss our previous Security Report? Click here to go to the archive.

 

Mobile Malware


Adups — The Spy in your Pocket

Smartphones have become inseparable companions of our everyday life. They are so cheap nowadays, you can buy commodity devices running Android OS for less than a hundred Swiss francs. Smartphones aren’t mere wireless telephony devices. They are modern computer systems equipped with a variety of sensors: cameras, microphone, GPS receiver, gyroscopes and accelerometers, etc. They also feature multiple wireless communication interfaces such as multi-generation mobile networking, 2.4 and 5 GHz Wi-Fi, Bluetooth, NFC, etc, which make them a polyvalent communication platform with a quasi permanent Internet connection. Another way of looking at it: using all the components typical smartphones are equipped with, they can be fitted as perfect bugging devices.

On November 15th 2016, Kryptowire published a blog post revealing that „several models of Android mobile devices contained a firmware that collected sensitive personal data about their users and transmitted the data to third-party servers without disclosure or the users’ consent“. The sensitive data includes unique device and user identifiers, but also contact lists, call history, installed applications, and under circumstances text messages as well as fine grained location data. The said firmware originates from Adups, a Shanghai-based company specialized in mobile and IoT technologies. It is part of their FOTA product, a commercial replacement of Google’s Over-The-Air upgrade system, which is used to deploy firmware upgrades to the devices (hence the acronym: Firmware Over The Air). The FOTA component is pre-installed on various brands and models of Android devices manufactured in China. Being installed as a system APK, the software has unrestricted access to all data on the device and cannot be uninstalled.

 

HTTP request originating from a device affected by the Adups backdoor

HTTP request originating from a device affected by the Adups backdoor

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The Jan/Feb 2017 issue of our SWITCH Security Report is available!

Dear Reader!

A new issue of our monthly SWITCH Security Report has just been released.

The topics covered in this report are:

  • The Guardian going post-truth with WhatsApp story?
  • Fruitfly spyware lives long on Macs
  • Good malware – FBI in absurdity trap
  • Star Wars on Twitter – sleeping Twitter botnet with over 350,000 bots discovered

The Security Report is available in both English and German.

»»  Download the english report.      »»  Download the german report.

Did you miss our previous Security Report? Click here to go to the archive.

 


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Usage of .ch domain names for spamming malware Tofsee stopped

It is rare that a malware family uses .ch or .li domain names in their domain name generation algorithm (DGA). The last time I remember, that we had to take action against a malware using .ch or .li domain names was about 8 years ago. It was Conficker that infected millions of computers worldwide. The malware was generating about 500 .ch and .li domains a day to be potentially used as a command and control server. By then SWITCH joined the conficker working group to prevent the use of domain names by this malware.

Since then we have been watching the use of .ch and .li domain names in malware DGAs and prepared for this by making an agreement with the Registrar of Last Resort (RoLR) to prevent the registration of domain names used in DGA algorithms of malware.

This week the Swiss Govermental Computer Emergency Response Team (GovCERT) informed us about the malware Tofsee using .ch as one of the TLDs in its DGA. Continue reading


A file that wasn’t there

One of our minions (he was introduced in this blog entry a while ago) recently came to us asking for advice: he was about to automate yet another task, by using his Python-fu, and realized that he misses entries in the file system as well as in the registry.

Notably, he only sees this behaviour on 64bit-versions of the Windows operating system:

Windows Explorer (64bit) vs Python application (32bit)

Left: Windows Explorer (64bit) lists several folders and files.   Right: Python application (32bit) only lists the folder Microsoft.

The left image shows the folder C:\Windows\System32\Tasks as seen in the Windows Explorer, the right image as seen in a simple 32bit-python application. Only the subfolder Microsoft is listed there. Something is amiss.

 

Below is the code to produce the right image, when executed in a 32bit-version of Python:

import glob, os
for pathfilename in glob.glob(r"C:\Windows\System32\Tasks\*"):
    print pathfilename

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The December 2016 issue of our SWITCH Security Report is available!

Dear Reader!

A new issue of our monthly SWITCH Security Report has just been released.

The topics covered in this report are:

  • Power and cybercrime – massive quantities of user data stolen in two recent hacks
  • When supposed security add-ons actually spy on your browsing habits
  • Mirai part II – botnet knocks out 900,000 Telekom routers
  • It’s not all bad news – Avalanche botnet taken down

The Security Report is available in both English and German.

»»  Download the english report.      »»  Download the german report.

Did you miss our previous Security Report? Click here to go to the archive.