With apparently not that much effort or specialized tools, reporters with German outlet Spiegel were able to find the cell phone numbers, email addresses, and even some passwords belonging to National Security Adviser Mike Waltz, Director of National Intelligence Tulsi Gabbard, and Secretary of Defense Pete Hegseth, some of them definitely still in use and – importantly – linked to their Signal accounts, with the reporters concluding that it's "conceivable that foreign agents were privy to the Signal chat group in which Gabbard, Waltz and Hegseth discussed a military strike."
It gets even better: "It was particularly easy for DER SPIEGEL reporters to discover Hegseth's mobile number and email address. They turned to a commercial provider of contact information that is primarily used by companies for sales, marketing and recruitment." Lol.