SMS
Short Message Service
Text messaging; a weak MFA channel and a smishing vector.
SMS is the cellular text messaging service, widely used to deliver one time passcodes despite well known weaknesses. Messages are not end to end encrypted and can be intercepted through SIM swapping or signaling network flaws, so it is the weakest common multifactor channel. It is also the delivery vector for smishing, a phishing variant sent by text. The exam favors authenticator apps or hardware tokens over SMS when stronger assurance is required.
Looking SMS up is step one. Getting tested on it is step two.
A free account opens all 4 Domain 1 objectives, 271 exam-style questions with a lesson and a lab on each, a placement check that skips what you already know, and a dated plan. No card.
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