You need some common sense and a little of internet knowledge, be careful with phishing sites as these emulate well known sites but are not secure normally (http:// instead of https) and of course don't ever download and run anything without using a tool such as virustotal.com from an unknown source.
The links on the Bitcoin forum sometimes also unsafe. If the forum administrator on strictly monitored to avoid tar nick. Those who are skilled in information technology will find a way to steal passwords and your money. While managers will be responsible Bitcoin.