Hackers with access to the Signaling System 7 (SS7) used for connecting mobile networks across the world were able to gain access to Telegram messenger and email data of high-profile individuals in the cryptocurrency business.
Source: Hackers hijack Telegram, email accounts in SS7 mobile attack
Telegram SS7 attack
httpv://www.youtube.com/watch?v=dkvQqatURdM&ab_channel=ThomasBrewster