If you're a Yahoo Messenger user, you have surely received mass messages, usually sent to the entire list and able to exploit some members' naivety. As I said, the most used technique to steal a password is the sending of malicious links that usually try to install an ActiveX control on your computer and send your password to a remote address. It is very important to avoid clicking on dangerous or unknown links as well as refusing to open websites sent from unknown users.
It is often said that some hackers are able to steal a Yahoo Messenger password straight from their computers and using a remote connection. Wrong! No one is able to find a user's private data unless he allows for it. That's why it's very important to block any malicious attempt to connect to your computer as well as any anonymous remote connection.
The main question is: is it possible to steal a Yahoo Messenger username and password? Theoretically, yes. Practically, it's impossible. OK, so my password is safe but some friends are claiming their passwords were stolen by hackers. What happened? Usually, the users might think their account was stolen if they're unable to connect but there are numerous reasons for this error: bad connection, Yahoo temporary downtime or even a ban applied to the account for multiple reasons.
So, are we safe enough to use Yahoo Messenger without any threat? Of course not, but all you need to do is to block any unknown connection that might harm your computer and steal your private information. How? Using a firewall that gives you full control over your incoming and outcoming traffic...