Spyware

Spyware collects information on a user's activities without their consent. It may be installed on a system illegitimately, or as part of other software without the user's knowledge, for example as a program embedded in an application that collects information and periodically communicates back to its home site. Criminals use malware such as spyware to steal personal information, including usernames, passwords, and bank account numbers.

On phones, spyware that someone installs to watch another person is also called stalkerware. The FTC notes that these apps can let an abusive partner or ex-partner track the device's location, turn on the microphone to record phone conversations, read text messages and emails, see photos and videos, and watch online activity. They are designed to avoid detection, and some hide in the phone's settings under innocuous names such as "system service".

Signs that a phone may be monitored include a battery that drains faster than usual, unexpected data use, overheating, and the phone turning off and on unexpectedly. To protect a phone, the FTC advises keeping physical control of it, locking it with a passcode of at least six digits, updating the operating system and apps regularly, and turning on two-factor authentication for accounts. A full factory reset may remove stalkerware, but because removing it can alert an abuser, the FTC suggests contacting a domestic violence advocate first.