When you set a password, it is stored in a cookie in plain text. Every request you send to the wiki sends the cookie along with it. Again, this is sent in plain text.
If your password is compromised, a malicious user could gain access to the administrative interface of your wiki. By default, they won't be able to do much damage.
I will figure out a way to address this in a future version of Aneuch.
If you operate on a shared, unsecured machine (such as at an internet cafe or similar), this is a very obvious problem. If you forget to log out of your wiki before you leave the terminal, the cookie remains active for 1 year. A malicious user could easily gain access to your wiki by virtue of the cookie's existence.
To log out of your wiki, click the "Admin" link at the bottom of any page, and click the "Log out" button.