I was going to make a joke about Safari but exposed user passwords isn't really a joking matter.
In our search for various types of malicious code for Mac we recently came across a rather interesting peculiarity in Safari. It turns out that Safari for Mac OS, like many other contemporary browsers, can restore the previous browsing session. In other words, all the sites that were open in the previous session – even those that required authorization – can be restored in a few simple steps when the browser is launched. Convenient? Of course. Safe? No, unfortunately.