FlagThis — Daily Cybersecurity Intelligence Briefing

Russian state-sponsored threat actors have launched a targeted campaign to hijack Signal Messenger accounts by exploiting vulnerabilities in the Public Switched Telephone Network (PSTN) rather than the application's encryption. This shift toward identity-layer exploitation demonstrates a sophisticated strategic pivot to bypass End-to-End Encryption (E2EE) by compromising the telephony-based authentication process used for account registration.