SITUATION 1:

I was hired as an IT Security Consultant of a manufacturing company, this company was been hacked mercilessly and I was the one to fix the problem. The Company gave me 90 days and a budget of 1 million dollars to fix the problem.

The procedures I'll do in order for me to solve/fix the problem are the following:

1. Investigate regarding the incident.
2. Identify those persons that have the motives of doing the crime.
3. Identify what kind of system used by the one who committed the
crime to enter/invade the security system of the company.
4. Study the system used.
5. Make a security system that is stronger than the company's old security system.
6. Make the hacker pay for the crime he made.

SITUATION 2:

Even though the "worm" is harmless otherwise it can cause disturbance, still it is illegal because you are not licensed to make such things like that.
You are entering a private system,...and it is impossible that you cannot be traced because your professors are better than you. So I say NO.