Every web site you use which has account and login capabilities has a log out function (if not, it is a poorly designed site) which you may or may not use. So for the purposes of this tip, I want to share why not logging out when you are done can be dangerous. Please keep in mind, this is just one possible exploitation and it depends on the way the site you are using is designed as to whether or not it is applicable. I’m going to try to keep it simple, so here goes…

Some sites like to embed what’s called a session ID into the URL when you are logged into their site. Typically you can tell because there will be a long random string of characters in your address bar. The session ID provides a medium for your browser and the site’s server to communicate back and forth. Now, if you navigate away from this site directly, the site you navigate to can capture the URL you can from (which includes your session ID) as the referring URL and record this in their log files. As a result, the new site now has your session ID information and can access the old site as you (again, depending on how the site is designed).

If you log out of the web site, this (should at least) closes your session. This is why you get a lot of notices from banking sites asking you to immediately close your browser.

Again, this is just one possible exploit and it depends entirely on how the site is designed but it does go to show you what can happen even when you are trying to be cautious online.