Incidents

The first Tor Trojan for Android

Virus writers of Android Trojans have traditionally used Windows malware functionality as a template. Now, yet another technique from Windows Trojans has been implemented in malware for Android: for the first time we have detected an Android Trojan that uses a domain in the .onion pseudo zone as a C&C. The Trojan uses the anonymous Tor network built on a network of proxy servers. As well as providing users with anonymity, Tor makes it possible to display ‘anonymous’ sites in the .onion domain zone that can only be accessed in Tor.

tor_backdoor_01s

Backdoor.AndroidOS.Torec.a is a variation of the popular Orbot Tor client. The cybercriminals have added their own code to the application, though the Trojan doesn’t pass itself off as Orbot – it simply uses the functionality of the client.

tor_backdoor_02s

The Trojan can receive the following commands from the C&C:

tor_backdoor_03s

  • start/stop intercepting incoming SMSs
  • start/stop theft of outgoing SMSs
  • perform a USSD request
  • send telephone data to the C&C (telephone number, country, IMEI, model, OS version)
  • send the C&C a list of apps installed on the mobile device
  • send an SMS to a number specified in a command

There are pros and cons of using Tor. On the plus side, it is impossible to shutdown the C&C. One of the main disadvantages, however, is the need for additional code. For Backdoor.AndroidOS.Torec.a to use Tor it will have required a lot more code than that required for its own functionality.

The first Tor Trojan for Android

Your email address will not be published.

 

  1. Darren Chaker

    I heard about the release of this Trojan for Android and must say this is a very concise and well written post, with great visuals too. Keep up the good work!

Reports

APT trends report Q1 2022

This is our latest summary of advanced persistent threat (APT) activity, focusing on events that we observed during Q1 2022.

Lazarus Trojanized DeFi app for delivering malware

We recently discovered a Trojanized DeFi application that was compiled in November 2021. This application contains a legitimate program called DeFi Wallet that saves and manages a cryptocurrency wallet, but also implants a full-featured backdoor.

MoonBounce: the dark side of UEFI firmware

At the end of 2021, we inspected UEFI firmware that was tampered with to embed a malicious code we dub MoonBounce. In this report we describe how the MoonBounce implant works and how it is connected to APT41.

Subscribe to our weekly e-mails

The hottest research right in your inbox