Feds Warn SMS Authentication Is Unsafe

An anonymous reader quotes a report from Gizmodo: Hackers aligned with the Chinese government have infiltrated U.S. telecommunications infrastructure so deeply that it allowed the interception of unencrypted communications on a number of people, according to reports that first emerged in October. The operation, dubbed Salt Typhoon, apparently allowed hackers to listen to phone calls and nab text messages, and the penetration has been so extensive they haven't even been booted from the telecom networks yet. The Cybersecurity and Infrastructure Security Agency (CISA) issued guidance this week on best practices for protecting "highly targeted individuals," which includes a new warning (PDF) about text messages. "Do not use SMS as a second factor for authentication. SMS messages are not encrypted-a threat actor with access to a telecommunication provider's network who intercepts these messages can read them. SMS MFA is not phishing-resistant and is therefore not strong authentication for accounts of highly targeted individuals," the guidance, which has been posted online, reads. Not every service even allows for multi-factor authentication and sometimes text messages are the only option. But when you have a choice, it's better to use phishing-resistant methods like passkeys or authenticator apps. CISA prefaces its guidance by insisting it's only really speaking about high-value targets. The telecommunications hack mentioned above has been called the "worst hack in our nation's history," according to Sen. Mark Warner (D-VA).

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