Good article Jill.  A prime reason corporate IT depts are hit is old, unpatched server software, using known versions with known vulnerabilities.  Cost cutting measures such as only three running backups can kill you as well - 7 is best as the State found out years ago with an infection started on a Thursday.  By Monday the over writes would have wiped out any good copies.  Two of us happened to discover the infection from Kodiak, had read enough between us to recognize the attack and notified IT.  We dodged a bullet, the target files were all the State communication Autocad files.  Thousands.  We pushed for antivirus software on each pc, not just the servers and were told it was not needed.  We then got infected by Monkey B, one of the original viruses.  Ironically, one recent ransomware attack is Petya, based on Monkey B.  Arse Technica has a self recovery article here: http://arstechnica.com/security/2016/04/experts-crack-nasty-ransomware-that-took-crypto-extortion-to-new-heights/