Users of the TeamViewer remote-access service have been complaining in recent weeks about how their systems have been hacked into, unauthorized purchases made on their cards, their bank accounts emptied. Initially it was believed that this was due to a hack into TeamViewer itself, but the company has denied this. Instead, they have blamed password re-use, especially with millions of old passwords in the wild thanks to disclosed social network breaches.

Others have speculated that malware could be in use somehow, and that may be the case. We have evidence that trojanized TeamViewer installer packages have been used in a spam campaign that resulted in attackers gaining remote access to various systems. While this particular spam campaign used an old version of TeamViewer, we can’t dismiss the possibility of other attacks using newer versions.