A Google Android botnet has been spotted spamming messages pushing counterfeit medication.
According to Sophos, the activity represents the latest way to monetize Android botnets. Traditionally, mobile malware has made money by intercepting SMS messages used as part of two-factor authentication mechanisms for online banks and charging fees for premium-rate SMS messages. This botnet however is sending messages that push Viagra and Cialis.
“The messages appear to originate from compromised Google Android smartphones or tablets,” blogged Chet Wisniewski, senior security advisor for Sophos Canada. “All of the samples at SophosLabs have been sent through Yahoo!'s free mail service and contain correct headers and SPF signatures. The first samples we analyzed were text only, but some other samples also contain images.”
Sophos said it is unsure of the size of the botnet, though Sophos researcher Savio Lau said the amount of spam it is sending out is relatively low. The same botnet was also detailed here in a blog post by Microsoft security researcher Terry Zink.
“Luckily, Yahoo stamps the IP address in the headers of where the device connected to its service,” Zink blogged. “I looked up where the IPs are geo-located: Chile, Indonesia, Lebanon, Oman, Philippines, Russia, Saudi Arabia, Thailand, Ukraine, and Venezuela.”
“What’s unusual about these countries? I’ve written in the past that Android has the most malware compared to other smartphone platforms, but your odds of downloading and installing a malicious Android app is pretty low if you get it from the Android Marketplace,” Zink continued. “But if you get it from some guy in a back alley on the Internet, the odds go way up.”
Wisniewski speculated victims likely downloaded Trojanized pirated copies of paid Android applications. Users should exercise caution when downloading apps for their devices.
“You can imagine the cellular phone bill you might receive if your phone is being used to download and spam out thousands of these messages,” he added.