Praise be to Allah.
It is not permissible to cheat in exams, because of the general meaning of the evidence that forbids cheating, which includes cheating (or deceiving) in buying and selling, in giving advice, in contracts and treaties, in matters of trust, in school and university exams, and so on, because the Prophet (peace and blessings of Allaah be upon him) said: “The one who cheats (or deceives) us is not one of us.” Narrated by Muslim (101).
Muslim (102) also narrated from Abu Hurayrah (may Allaah be pleased with him) that the Messenger of Allaah (peace and blessings of Allaah be upon him) said: “Whoever cheats (or deceives) does not belong to me.”
This wording indicates that cheating and deceiving is forbidden in all cases, whether it is deceiving a Muslim or a kaafir.
Moreover, cheating in exams results in a number of negative consequences and sins, such as:
1-Taking what one is not entitled to, which is the certificate that results from the exam.
2-Consuming wealth unlawfully, if one gets a job with that certification.
3-Corruption of work, administration and specialities, due to the presence of one who is not qualified or suited for the work.
4-Involvement in bribery, for which those who are engaged in it are cursed, if the one who is cheating pays someone money to enable him to cheat.
Moreover, these people who cheat in the kaafir lands bring these certificates back to the Muslim lands, and some of them reach high positions, so the matter affects Muslims too, and he may be deceiving Muslims as well.
To sum up, all kinds of cheating and deceiving are haraam, and it is an evil and corruption, whether it happens in a Muslim land or in a kaafir land. What the one who has done that must do is repent to Allaah and not do it again.
And Allaah knows best.