Is helping students in open-source electronic exams—whether by guiding them or taking the exam on their behalf—permissible in Islamic law, and is the money earned from this halal, or does it fall under the ruling of cheating?

It is impermissible to solve exams for students, even for free. Any earnings acquired through such an act are considered unlawful gains (haram) and must be disposed of by giving them to the poor and needy, because this act constitutes cheating. The exam is intended for the student to solve on their own, and helping others in this regard is cooperating in sin. Allah Almighty says: "And do not cooperate in sin and aggression." The Prophet, peace and blessings be upon him, said: "Whoever cheats us is not of us." Repentance requires abstaining from the act, feeling remorse, resolving not to return to it, and disposing of any money gained from it.