From email address to phone number

Presented at BSidesLV 2019, Aug. 7, 2019, noon (25 minutes).

Email addresses are one of our most public piece of PII. We are comfortable sharing it with strangers, publishing it on the internet and it is generally our public way of communicating.

However, when it comes to phone numbers things change. We are more selective with who we share it with, mostly because receiving unsolicited phone calls is much more invasive. There are also security implications when making your phone number publicly available. SS7 attacks, SIM swapping, phishing and scam calls are just a few of the threats that originate from the target's phone number.

What if it were possible to obtain someone's phone number by only knowing their email address? Beyond the criminal advantage, it could be very useful to investigators, red teams and OSINT lovers.

In this talk, I will discuss techniques which when combined will let you discover someone's phone number via their email address. I will also demo and release a tool that helps automate the process.


Presenters:

  • Martin Vigo
    Martin Vigo is a red teamer and researcher with a background in product security and software engineering. He previously focused on Mobile security, Identity and Authentication, helping keep "the cloud" secure. Since then, he has shifted to pure offensive security work, putting on the black hat to catch the bad guys. Martín is also involved in educating developers on security essentials and best practices. Martin has presented several topics including accounts takeover by voicemail cracking, breaking password managers, exploiting Apple's Facetime to create a spy program and mobile app development best practices. These were given at conferences such as DEF CON, Blackhat EU, Ekoparty, BSides Las Vegas, Kaspersky Security Analyst Summit and Shakacon. Outside the office, Martin enjoys research, bug bounties, gin tonics and scuba diving.

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