Covert Affairs/WMG

Henry Wilcox is the mysterious leak.
Henry Wilcox is known to run black ops - he's the freakin' Prince of Darkness, for crying out loud. He's the only person who could avoid Arthur's polygraph test, because he's technically not part of the agency. His son, Jai, knows Ben. He's framed Ben for the leak, so Joan and Arthur are hunting him down. Ben thinks Joan and Arthur have betrayed him. Really, he's pitting them against each other as part of his master plan.
 * Confirmed in the first season finale, when Liza Hearns gets into a car with him and he makes a comment about "getting her to win that Pulitzer Prize."

Ben's mission in Sri Lanka was connected to Auggie's mission in Iraq.
They both happened around the same time, and were both dark ops. Perhaps Ben's screw-up in Sri Lanka led to Auggie's IED?