Strange software, especially mobile apps
You know not to download strange software on your computer, or download directly from trusted vendor websites or other reputable sources. Don't forget to take the same precautions on your mobile device. Android phones in particular are vulnerable because of the more open nature of the ecosystem. Some malware disguises itself as legitimate apps that people are searching for. Or even as anti-virus software. Check reviews carefully before downloading, and stick with reputable app stores. Malicious apps can track what you type, stealing all your passwords, or send texts to premium rate numbers, racking up big charges for you, and big profits for them.