Ruling on forging the lecturer’s signature to prove attendance in a graduate studies program

Some medical schools require graduate students to attend a certain number of lectures and clinics in order to be allowed to enter the final exam for the Masters degree. Because graduate students are doctors who are working and most of them are married or have military service, and have commitments that make them unable to attend these lectures, they have resorted to forging the lecturer’s signature in their notebooks. 
Please note that the college is aware of this because the number of people attending the lecturers is far lower than that of those who apply to sit the exam. Although the administration of the college is aware of that, it turns a blind eye and does not refuse to accept the notebooks that contain forged signatures. Some people have tried to ask the administration to allow them to enter the exam without these notebooks, but the administration has refused.
I hope that you can explain the fiqhi ruling on what these students are doing.