By Dancho Danchev
Have you ever received a blank call, and no one was on the other side of the line? What about a similar blank SMS received through your mobile carrier’s Mail2SMS gateway? There’s a high probability that it was a mobile spammer who’s automatically and efficiently verifying the validity of a recently harvested database of mobile numbers, with QA (Quality Assurance) in mind. These verified databases will be later on used as the foundation for a highly successful spam/scam/malicious software disseminating campaigns, thanks to the fact that the cybercriminals behind them will no longer be shooting into the dark. How do they do that? What kind of tools do they use?
Let’s find out by profiling a Russian DIY (do it yourself) software vendor, that’s been operating since 2011, and is currently offering a Session Initiation Protocol (SIP) based phone number verification tool, as well as USB-modem based phone number verification application.