Android Malware DroidDream: How it Works

Yesterday, Google pulled more than 50 apps from the Android Market after they were found to contain the Android malware dubbed DroidDream. Similar to previous instances of Android malware that have been found on alternative Android app markets, the authors of DroidDream hid the malware in seemingly legitimate applications to trick unsuspecting users into downloading the malware—a growing trend in mobile threats. We also discovered that these apps were placed in alternative app markets in addition to the Android Market.

The Lookout Security Team did a deep analysis of the DroidDream malware present in one of the infected applications, Bowling Time. Below we’ve included details on how the first phase of the malware works when installed on a phone. We are continuing to analyze DroidDream in more detail and will update this post with additional results.

In the DroidDream samples we have analyzed, the malware cannot start automatically: it requires the user to manually run the infected application. When the host application—Bowling Time, in this case—is launched by a user, DroidDream will start by sending sensitive data to a command and control server. The sensitive data includes:

• IMEI
• IMSI
• Device Model
• SDK Version

DroidDream is configured to perform at least one successful check-in with the command and control server, at which point the command and control server will respond and acknowledge the presence of malware on the infected device. We found that the DroidDream authors have configured the malware to make sure the device is not already infected with another variant of DroidDream. If the device is already infected, the malware will not re-infect it. Continue reading…