Sockbot Ensnares Android Devices into Botnet

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A newly discovered Android malware has the ability to add the compromised devices to a botnet that could potentially launch distributed denial-of-service (DDoS) attacks, Symantec warns.

Dubbed Sockbot, the highly prevalent threat was found masquerading as legitimate apps in Google Play. Symantec has discovered eight such applications and says that they have been downloaded between 600,000 and 2.6 million times.

The malware is mainly targeting users in the United States, but some of the infected devices are located in Russia, Ukraine, Brazil, and Germany, the security researchers say.

The applications hiding the malware were designed to modify the look of the characters in Minecraft: Pocket Edition (PE). In the background, however, they enable sophisticated and well-disguised attacking functionality.

The malicious app connects to a command and control (C&C) server on port 9001. The server requests the app to open a socket using SOCKS and wait for a connection, which arrives along with a command to connect to a target server.

After connecting to the target server, the application receives a list of ads and associated metadata. Through the SOCKS proxy mechanism, the app is also pointed to an ad server and commanded to launch ad requests. However, the security researchers discovered that the decoy app doesn’t include functionality to display ads.

“This highly flexible proxy topology could easily be extended to take advantage of a number of network-based vulnerabilities, and could potentially span security boundaries. In addition to enabling arbitrary network attacks, the large footprint of this infection could also be leveraged to mount a distributed denial of service (DDoS) attack,” Symantec reveals.

The infection campaign was tracked to a single developer account named FunBaster and each app was signed with a different developer key, likely in an attempt to avoid static analysis-based heuristics. The malicious code is also obfuscated and features encrypted key strings, thus thwarting base-level forms of detection.

Symantec informed Google on the presence of these malicious apps in the application store and the Internet giant has already removed them.

In August this year, security companies worked together to take down a large Android botnet. Called WireX, it was designed to launch DDoS attacks, and one variant was capable of launching high-volume UDP flood attacks, the researchers discovered.

Related: How Collaboration and Information Sharing Can Neutralize Adversaries

Related: Variant of Android WireX Bot Delivers Powerful UDP Flood Attacks

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Ionut Arghire is an international correspondent for SecurityWeek.

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