Mobile security issues: unofficial app stores, jailbreaking and rooting, sideloaded APKs, high network traffic, data-limit alerts, sluggish response, fake security warnings, unexpected app behavior, leaked personal files

Mobile devices are protected mainly by two things: official app stores that screen apps before publishing them, and an operating system sandbox that keeps each app isolated from other apps and from the system. Most mobile security problems begin when a user weakens one of those protections. This topic splits naturally into causes (what weakened the device) and symptoms (what you notice when something is wrong), and the exam expects you to tell them apart and choose the right response.