Tag Archives: Mobile Number

DIY SIP-based TDoS tool/number validity checker offered for sale

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By Dancho Danchev

Over the past year, we observed an increase in publicly available managed TDoS (Telephony Denial of Service) services. We attribute this increase to the achieved ‘malicious economies of scale’ on behalf of the cybercriminals operating them, as well as the overall availability of proprietary/public DIY phone ring/SMS-based TDoS tools.

What are cybercriminals up to in terms of TDoS attack tools? Let’s take a peek inside a recently released DIY SIP-based (Session Initiation Protocol) flood tool, which also has the capacity to validate any given set of phone numbers.

More details: Continue reading →

DIY Russian mobile number harvesting tool spotted in the wild

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By Dancho Danchev

Earlier this year we profiled a newly released mobile/phone number harvesting application, a common tool in the arsenal of mobile spammers, as well as vendors of mobile spam services. Since the practice is an inseparable part of the mobile spamming process, cybercriminals continue periodically releasing new mobile number harvesting applications, update their features, but most interestingly, continue exclusively targeting Russian users.

In this post, I’ll profile yet another DIY mobile number harvesting tool available on the underground marketplace since 2011, and emphasize on its most recent (2013) updated feature, namely, the use of proxies.

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How mobile spammers verify the validity of harvested phone numbers

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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.

More details:

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