CAC, or customer acquisition cost, is the total spend required to win a new customer. It includes paid ads, sales labor, promotions, onboarding, and the operational cost of turning a lead into a paying user. In analytics, CAC helps teams compare the cost of growth against the value of each customer.
In cyber security, CAC matters because attacks often distort acquisition economics. Click fraud, bot sign-ups, affiliate abuse, fake reviews, and account creation abuse can raise CAC by wasting ad spend or polluting conversion data. Defenders watch CAC alongside conversion rate, cohort quality, and fraud signals to spot suspicious traffic or manipulated funnels. A sudden rise in CAC can indicate low-quality leads, automated abuse, or reputation attacks that reduce trust before a purchase.