May 22, 2013

Russian anti-virus company Doctor Web is warning users about a new Trojan for Android that can intercept inbound short messages and forward them to criminals. Android.Pincer.2.origin poses a serious threat because stolen messages can contain sensitive information such as mTAN codes which are used to confirm online banking transactions.

The Trojan, discovered by Doctor Web's analysts several days ago, is a second representative of the Android.Pincer malware family. Like its predecessor, this malicious program is spread as a security certificate that supposedly must be installed onto an Android device. If a careless user does install the program and attempts to launch it, Android.Pincer.2.origin will display a fake notification about the certificate’s successful installation and will not perform any noticeable activities for a while.

To be loaded at startup, the Trojan will make sure that its process —CheckCommandServices — will be run as a background service.

If at some point Android.Pincer.2.origin is launched successfully at startup, it will connect to a remote server and send it information about the mobile device, including:

• Handset model
• Device's serial number
• IMEI
• Carrier
• Cell phone number
• Default system language
• Operating system
• Availability of the root account

After that, the program awaits instructions that contain commands in the following format: "command:[command]". The following directives can be sent to the malware by criminals:

• start_sms_forwarding [telephone number]— begin intercepting communications from a specified number
• stop_sms_forwarding — stop intercepting messages
• send_sms [phone number and text] — send a short message using the specified parameters
• simple_execute_ussd — send a USSD message
• stop_program—stop working
• show_message—display a message on the screen of the mobile device
• set_urls - change the address of the control server
• ping - send an SMS containing the text 'pong to a previously specified number
• set_sms_number—change the number to which messages containing the text string 'pong' are sent.

The command start_sms_forwarding is of particular interest since it allows attackers to indicate the number from which the Trojan needs to intercept messages. This feature enables criminals to use the Trojan for targeted attacks and steal specific messages, for example, those received from banking services and containing mTAN codes or other messages containing sensitive information.

Dr.Web anti-viruses for Android successfully detect Android.Pincer.2.origin and pose no threat to devices protected by Doctor Web software.