Bit9

Bit9 said a common Web application vulnerability was responsible for allowing hackers to ironically use the security vendor's systems as a launch pad for attacks on other organizations.

Based in Waltham, Mass., the company sells a security platform that is designed in part to stop hackers from installing their own malicious software. In an embarrassing admission, Bit9 said earlier this month that it neglected to install its own software on a part of its network, which lead to the compromise.

It was five months before the intrusion at Bit9 was detected.

According to research by security blogger Brian Krebs, hackers breached Bit9 in July 2012, yet this was not discovered until January 2013.