Android users are facing a new threat in the form of SpamSoldier, a piece of malware gaining a foothold on all major US carrier networks. SpamSoldier is hidden as part of another package such as a game or app that the user willingly installs. Once installed, the phone is hijacked to send out spam SMS messages in blocks of 100. All traces of the sent messages are removed, so the user is unaware that their phone is part of a growing botnet.

Typical messages invite users to download free games and apps (which are of course also infected) or direct the user to collect a $1,000 gift card by following a link.

In mid-December, the number of infected devices was clocked at roughly 1,000 and growing fast across all major carrier networks. If detected, the typical response from a carrier is to block all SMS messages from an infected smartphone. While effective and stemming the spread, it can be a serious inconvenience to users who may rely on that service.