Neither Regular or secure mode of Imail properly give out a hash on cookies leaving the cookies straight readable to any onlookers.

No exploit is needed
POC: 

"IMail_UserId
1006332dgd2@Someserver"
--------------------------
"IMail_password
1234"

Straight From Cookie ^^ (edited to protect user)

Shoutz to Dcrab, Infinite, j0X, DjPc, Ch4r, Raven, FPA, woody, elohimus, kurupt3k, and the rest i forgot i still got love for :P