If the bank sends verification code while transferring then, he can't. But if he uses some hacking knowledge it is possible. Why don't u change ur password ?

i don't know about CBE but mobile banking (*889#) it is possible if the guy who got ur pasword have some knowlege on security like hacking

I can't ! your mobile bank is open by the number you hold . even if he know your secret number of your CBE account i cant transfer yr birr.

I'm not sure how it rly works but it's best you change your password immediately and report it