If the verb "bring" is 가져오다 or 가져가다, what will be the passive of it? Because it seems there is no passive form for 오다 or 가다.
I don't think 가져오다/가져가다 has a passive form. Instead you will use active form or different verbs depending on context - note that in Korean one can easily "emphasize the object" by changing word order or using topic marker -은/는.
So, for example:
The box was brought here by me. -> 그 상자는 내가 가져왔다. (Active form, but "the box" is the topic.)
The box was brought here on a cart. -> 그 상자는 카트에 실려왔다. (Alternative passive verb.)
The new insect species was then brought to America. -> 이 새로운 종의 곤충은 이후 아메리카로 전파되었다.