We don't know. If it was, do you really think it would be their only operation? Who else would have both the capability to massively MITM SSL within a geographical area? I'm not suggesting it was the Iranian government (to clarify, neither was my post above), but for someone to go after the certs it would be expected they'd want to have somewhere (or at least someone) to MITM in mind.

How many Iranians use Yahoo Mail? How many people of interest outside of Iran use Yahoo Mail?