A systems administrator receives a text message from an unknown number claiming to be the Chief Executive Officer of the company. The message states an emergency situation requires a password reset. Which of the following threat vectors is being used?

Smishing is correct because it describes a phishing attack conducted via SMS text message. The attacker is attempting to trick the recipient into revealing sensitive information (like a password) by impersonating a trusted authority (the CEO) through a text message. Typosquatting is incorrect because it involves registering domain names similar to legitimate ones to trick users who mistype URLs. Pretexting is incorrect because while it involves creating a fabricated scenario to gain information, it's a broader social engineering technique and doesn't specifically refer to the SMS delivery method. Impersonation is incorrect because it's a general social engineering tactic where an attacker pretends to be someone else, but it doesn't specify the use of text messages as the attack vector.