content: The FBI can just use one of those zero-days in Windows which Microsoft knows about but which hasn't gotten patched yet. Remember, the government gets informed about these things first.  http://www.bleepingcomputer.com/news/security/google-discloses-windows-zero-day-before-microsoft-can-issue-patch/ A firewall will do little good if you load a web page and the embedded video takes over the machine, or the loading of a PDF leads to complete compromise.