Excerpts:

“Meanwhile, the CBN official who handles the funding is an uncle to three of those arrested in connection with the Nyanya bombings. The three boys lived with him. They were arrested by the SSS (Department of State Security) after the bombings but they do not seem to have been interrogated about their uncle in CBN. Or if they have given up information about their uncle then the SSS has not moved against him.”

“Also, a senior official of CBN, who recently left the bank, was very close to Sodiq Aminu Ogwuche, the mastermind of the Nyanya bombings who also schooled in Sudan. Boko haram commanders said Ogwuche’s wife used to visit this top official in his office at the headquarters of the bank in Abuja before the Nyanya bombings. They were very close,” Davis said.

http://www.thecable.ng/exclusive-boko-haram-funded-through-cbn
http://saharareporters.com/2014/08/31/australian-negotiator-insists-modu-sheriff-ihejirika-sponsor-boko-haram-exonerates-buhari

Stephen Davis, an Australian hostage negotiator who spent some time in Nigeria trying to secure the release of more than 200 Nigerian schoolgirls abducted by Boko Haram militants in Chibok, Borno State, told SaharaReporters that he stands by his widely reported allegations that former Governor Modu Sherriff of Borno State and a former Chief of Army staff, General Azubuike Ihejirika (ret.), were among the top sponsors of the Islamist insurgents who have massacred thousands of Nigerians and foreigners and made the northeast part of Nigeria a highly militarized zone.

So you see why the Army has been useless; and Boko Haram have been using Army supplied weapons.