Just scratching the surface:
Overall, the number of Bureau of Diplomatic Security (DS) security staff in Benghazi on the day of the attack and in the months and weeks leading up to it was inadequate, despite repeated requests from Special Mission Benghazi and Embassy Tripoli for additional staffing. - page 5
At the same time, the SMCs (U.S. Special Mission compound) dependence on the armed but poorly skilled Libyan February 17 Martyrs Brigade (February 17) militia members.... - page 5
http://www.state.gov/documents/organization/202446.pdf
The February 17th Martyrs Brigade are Islamic terrorists. It is/was led by Fawzi Bukatef, Muslim Brotherhood.
This occurred on Clinton’s watch.
Oct 10, 2012 - The State Department acknowledged Wednesday that it rejected appeals for more security at its diplomatic posts in Libya in the months before a fatal terrorist attack in Benghazi