A user reports that their smartphone frequently displays pop-ups that warn of security threats and...

The symptoms point to malicious or rogue content: frequent “security warning” pop-ups that push “tools” is a classic sign of scam/rogue apps, and the new fast battery drain suggests an unwanted process running in the background. The CompTIA objectives explicitly list mobile security symptoms such as “high number of ads,” “fake security warnings,” and “unexpected application behavior,” which aligns with this scenario. On the browser side, Quentin Docter notes that if you continually receive pop-ups or overlays, “you may be infected with malware,” and recommends scanning with antivirus/antimalware software. He also explains that clearing browsing data/cache is sometimes necessary to resolve browser-related problems and details how to clear cache/browsing data.

Because the user tapped the pop-up and then battery life worsened, the best practical fix is to remove the likely malicious application(s) (uninstall unknown apps) and clear browser cache to eliminate stored site data/scripts fueling the pop-ups. A factory reset is a stronger last resort, but least disruptive remediation is A.