FluBot is a new Android malware first discovered in December 2020. During the first few months, FluBot has been active in Spain, Hungary and Poland. Since then, the development of the malware advanced quickly and the malware has set foot in almost all European countries.
On the 18th of June 2021 FluBot version 4.6 was spotted which added a configuration for Switzerland. As of today it is actively being spamertized through SMS.
FluBot is known by different names. The name “FluBot” is best known because this was the name given in the first public technical writing. Below the reference to the most well known aliases:
January 2021, ThreatFabric was the first to give it the name “Cabassous” in a Twitter post
March 2021, ProDaft published a detailed technical report and gave it the name “FluBot”
April 2021, IBM Trusteer took a deeper look at the different FluBot versions and gave it the name “FakeChat“
FluBot is distributed using smishing (a combination from the words SMS and phishing). The victim receives an SMS with a link to an URL which distributes the APK. The installation is straight forward using sideloading.
Rogue mobile apps are counterfeit apps designed to mimic trusted brands or apps with non-advertised malicious features. In both cases, the goal is that unaware users install the app in order to steal sensitive information such as credit card data or login credentials.
The common way to install apps is to use the official app store. By default, neither Android nor Apple’s iPhone allow users to install apps from unknown sources. However, this does not mean we can just trust the official app store. SWITCH-CERT has been monitoring Apple’s App Store and Google Play for some time and noticed that many rogue apps are able to sneak into Google Play especially.
Attackers are abusing the weak app testing procedure of Google to sneak their rogue apps into Google Play. One can find counterfeit apps of Swiss brands on a regular basis. Typically, the apps reside on Google Play for some time until it is removed because of take down requests from security researchers. Until that happens, unaware users are likely to install such apps and put their data at risk.
The screenshot below shows apps found when searching for Bluewin. During the last months, Bluewin has been a common target for rogue counterfeit apps. The red circle indicates the rogue app.
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.