I found an ayah which could answer your question:
Abraham was neither a Jew nor a Christian, but he was one inclining toward truth, a Muslim [submitting to Allah ]. And he was not of the polytheists. (3:67).
As will be explained below the word Muslim doesn't just belong to Islam. Although Abraham hadn't had the Koran Allah describes him as a Muslim, too.
As we know the general meaning of Muslim is submission to Allah/God, and it shows that everybody can become a Muslim as long as he/she believes in one God/Allah and is righteousness (read Sura Asr)
The following ayah could also be interesting for answering your question:
Who receiveth guidance, receiveth it for his own benefit: who goeth astray doth so to his own loss: No bearer of burdens can bear the burden of another: nor would We visit with Our Wrath until We had sent an messenger (to give warning). (17:15)
So we can assume that Allah had sent at least one prophet to each nation to teach the
truth and the right way. In my opinion these prophets had sent the same message of Allah, but due to the the cultural differences in other societies it was an other type of an abrahamic monotheistic religion. However this is my personal point of view...
Addtionionally, sura Asr teaches us how to prevent becoming a kafir:
Indeed, mankind is in loss,
Except for those who have believed and done righteous deeds and advised each other to truth and advised each other to patience.
In the sura above the key words to become a Muslim are iman (faith), amiableness, teaching of truth, Patience and Constancy.
I can't imagine that Allah punishes anyone only because of his non-abrahmic religion or who comes from a society where Allah didn't sent a messenger. Of course, Allah knows best...