Syria’s Bashar al-Assad condemns Friday’s attack:

[leveymg]

17. As usual, Damascus was playing both sides of the Iraq War, and suffered the consequences

Recall that the Bush Administration shortly before was also using Syria as a place to deposit early batches of AQ detainees for "enhanced interrogation" before the CIA brought that sort of thing in-house.

Anyway, you are right that it was reported that Assad's assassinated brother, then the head of military intelligence, was permitting AQ to transit Syria into Iraq: http://foreignpolicy.com/2012/10/01/the-generals-gambit/

The point was underscored by U.S. intelligence assessments, which noted that the route the would-be jihadists took to the war was also their way out. Foreign fighters "who gained operational experience while fighting in Iraq return to their source countries through Syria," one such report observed. "These experienced fighters returning from jihad pose a threat to the Syrian regime. Although Syria currently is mainly a transit point for AQI, Syria will be an AQI target in the future. AQI ultimately intends to conduct attacks in Syria."