Yes, it is! They can also include clauses that the company's code and other materials won't be shared with 3rd parties, aka an NDA. These are standard and well

Yes, it is! They can also include clauses that the company's code and other materials won't be shared with 3rd parties, aka an NDA. These are standard and well-accepted practice. The contract will also be very clear that access to the systems is only granted to the person signing the contract. They don't get to grant access to other people just because they have contractor status.