Is money earned from private work during official working hours permissible, considering that there is a lot of free time and the company does not benefit from this work?

An employee, whether on overtime or regular duty, is considered a private contractor who is entitled to wages if he dedicates himself to the work, even if there is no work available or he is permitted to leave. An employee may use the computer for personal matters during idle time if it does not affect work and the use of work equipment is permitted by text or custom. However, working for another party during official working hours, even during idle times, is not permissible without the employer's permission.