Android Botnet Uses Twitter for C&C

There is an Android backdoor that connects to a Twitter account instead of a command and control (C&C) server, researchers said.

Android/Twitoor is able to download other malicious applications onto the infected devices and has been active for around a month, said researchers at ESET. The threat isn’t spreading through official Android storefronts, but through SMS or malicious URLs sent to its victims.

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The backdoor is impersonating a porn player application or MMS program, but it does not present the functionality such software would normally have, ESET researchers said. After launching, the malware hides its presence on the infected device and starts checking a defined Twitter account at regular intervals for commands.

Depending on the commands it receives, the backdoor can either download malicious applications onto the compromised device or can switch to a different C&C Twitter account, researchers discovered.

“Using Twitter instead of command-and-control (C&C) servers is pretty innovative for an Android botnet,” Lukáš Štefanko, ESET’s malware researcher who discovered the malicious app, said in a post. “Twitoor serves as another example of how cybercriminals keep on innovating their business,”

ESET researchers said malware that turns devices into botnets requires communication with a C&C server to receive updated instructions, and this communication could raise suspicion from users. In addition, when these servers end up seized, they tend to disclose information about the entire botnet.

To ensure Twitoor botnet’s communication is more resilient, the malware authors decided to encrypt the transmitted messages. They also used complex topologies of the C&C network and new communication methods, such as social networks.

Štefanko also said Twitoor is the first Twitter-based bot malware for Android.