A newly discovered backdoor that has managed to infect over one thousand Android devices was designed to steal sensitive data from popular social media applications, Google reveals.
Dubbed Tizi, the malware comes with rooting capabilities and has been already used in a series of targeted attacks against victims in African countries such as Kenya, Nigeria, and Tanzania. Discovered by the Google Play Protect team in September 2017, the backdoor appears to have been in use since October 2015.
A fully featured backdoor, Tizi installs spyware that allows it to steal sensitive data from the targeted applications, Google says. The malware family attempts to exploit old vulnerabilities to gain root access on the infected Android devices, and its developer also uses a website and social media to lure users into installing more apps from Google Play and third-party websites.
To date, Google has identified over 1,300 devices affected by the malware. According to the company, newer Tizi variants include rooting capabilities that attempt to exploit a series of local vulnerabilities, including CVE-2012-4220, CVE-2013-2596, CVE-2013-2597, CVE-2013-2595, CVE-2013-2094, CVE-2013-6282, CVE-2014-3153, CVE-2015-3636, and CVE-2015-1805.
Since most of these vulnerabilities target older chipsets, devices, and Android versions, users running a security patch level of April 2016 or later are far less exposed to Tizi's capabilities. If none of the exploits work, the Tizi apps attempting to gain root will switch to perform the action through the high level of permissions it asks from the user.
Once it has gained root on the compromised device, the threat can proceed to stealing sensitive data from popular social media apps such as Facebook, Twitter, WhatsApp, Viber, Skype, LinkedIn, and Telegram.
After infection, the malware usually contacts its command and control (C&C) by sending an SMS with the device's GPS coordinates to a specific number. Subsequent communication with the C&C, however, is performed over HTTPS, but some versions of the malware also use the MQTT messaging protocol to connect to a custom server.
“The backdoor contains various capabilities common to commercial spyware, such as recording calls from WhatsApp, Viber, and Skype; sending and receiving SMS messages; and accessing calendar events, call log, contacts, photos, Wi-Fi encryption keys, and a list of all installed apps,” Google says.
On top of that, however, the malware can also record ambient audio and take pictures without displaying the image on the device's screen.
To stay safe, users are advised to pay close attention to the permissions they grant to newly installed applications; to enable a secure lock screen, such as PIN, pattern, or password; keeping their devices up-to-date at all times, given that the threat exploits old, known vulnerabilities; and ensure Google Play Protect is enabled.