title: Am I under risk of CSRF attacks in a POST form that doesn't require the user to be logged in?
body: <p>I'm probably being a total noob here, but I'm still uncertain about what a CSRF (Cross-Site Request Forgery) attack is exactly. So lets look at three situations...</p>
  
  <p>1) I have a POST form that I use to edit data on my site. I want this data to be edited <em>only</em> by users that are logged in.</p>
  
  <p>2) I have a site, which can be used by both users who are logged in as well as guests. Parts of the site are for logged in users only, but there are also POST forms that can be used by all users - anonymous and not (for example a standard contact form). Should the contact form be safeguarded against CSRF attacks?</p>
  
  <p>3) I have a site which doesn't have an authentication system at all (well, perhaps that's unrealistic, so lets say it has an admin site which is separate from the rest of it and the admin part is properly safeguarded). The main part of the site is only used by anonymous users. Do the POST forms on it need to be safeguarded?</p>
  
  <p>In the case of 1) the answer is clearly yes. But in the case of 2 and 3 I don't know (and is the difference between 2 and 3 even significant?).</p>