The Philippines does have a corruption problem. Open sources are very clear on insurgents being able to purchase arms and equipment from high ranking military officials. Terrorists and criminals routinely buy their way out of capture or prison. Al Ghozi's 'escape' from prison is a perfect example, albiet a brazen and clumsy one. The U.S. hostages of the Abu Sayyaf also reported that the ASG would often pay their way out of trouble when they were cornered. A game of cat and mouse that benefited both sides.
Most of this has been able to flourish because the southern Philippines has been a relative backwater until recently. Now that the scrunity is intensifying, it will be harder for people to play both sides.