A recently deomstrated vulnerability in the OpenSSL package on Debian Linux distribution has generated numerous certificates weak and are easy to crack. Many servers still use these weak certificates, even though it is impossible to establish a secure connection using them. The heise SSL Guardian checks the SSL certificates and warns you when it detects a weak one.
As always, it is important that you be very sure that the website is legitemate, if you choose to continue browsing the webpage. Also, you may report the certificate to report online to heise server.
Click here to download and install Heise SSL Guardian. The add-on works on Windows Vista/XP and earlier on Internet Explorer 7 and earlier. Once installed, Heise SSL Guardian will open a test page with a bad certificate to test if it works OK.
If you are a Firefox user, ensure you update to Firefox 3.0 and follow this article here to install Perspective & SSL Blacklist extensions to protect yourself on HTTPS websites.