Email spammed out this weekend pretending to be an advisory about a new update to the popular Firefox web browser. The link downloads an executable file, which bundles together an installer for Mozilla Firefox 5.0.1 and a password-stealing Trojan horse. A Firefox update will not make any changes to your bookmarks, saved passwords or other settings. There is a possibility that some of your Add-ons won’t be immediately compatible with new updates. You should always exercise caution when you’re asked to click on a link in an unsolicited email.”]
Source: https://nakedsecurity.sophos.com/2011/08/08/fake-firefox-update-email-malware/