What could indicate a malicious code attack?

A new app appearing on the device unexpectedly is a significant indicator of a potential malicious code attack. This occurrence could suggest that unauthorized software has been installed without the user's knowledge or consent, which is a common method used by cybercriminals to implement malicious code on a device. Such apps might be designed to steal data, track user behavior, or perform other harmful actions while remaining hidden from the user.

In contrast, an improvement in battery life generally does not correlate with malicious activity; rather, it might simply indicate that the device is running more efficiently, possibly after an update. Similarly, a device that runs updates swiftly typically reflects efficient software processes and isn't indicative of an attack. Lastly, if there's no change in device performance, it might suggest that everything is functioning normally, which wouldn't raise any suspicions regarding malicious activity. Thus, the unexpected appearance of an app is the most telling sign of a harmful intrusion.