I was involved in disclosing a vulnerability found by a student to a production web site using custom software (i.e., we didn't have access to the source code or configuration information). As luck would have it, the web site got hacked. I had to talk to a detective in the resulting police investigation. Nothing bad happened to me, but it could have, for two reasons. The first reason is that whenever you do something "unnecessary", such as reporting a vulnerability, police wonder why, and how you found out. Police also wonders if you found one vulnerability, could you have found more and not reported them? Who did you disclose that information to? Did you get into the web site, and do anything there that you shouldn't have? It's normal for the police to think that way. They have to. Unfortunately, it makes it very uninteresting to report any problems. A typical difficulty encountered by vulnerability researchers is that administrators or programmers often deny that a problem is exploitable or is of any consequence, and request a proof. This got Eric McCarty in trouble -- the proof is automatically a proof that you breached the law, and can be used to prosecute you! Thankfully, the administrators of the web site believed our report without trapping us by requesting a proof in the form of an exploit and fixed it in record time. We could have been in trouble if we had believed that a request for a proof was an authorization to perform penetration testing. I believe that I would have requested a signed authorization before doing it, but it is easy to imagine a well-meaning student being not as cautious (or I could have forgotten to request the written authorization, or they could have refused to provide it...). Because the vulnerability was fixed in record time, it also protected us from being accused of the subsequent break-in, which happened after the vulnerability was fixed, and therefore had to use some other means. If there had been an overlap in time, we could have become suspects. The second reason that bad things could have happened to me is that I'm stubborn and believe that in a university setting, it should be acceptable for students who stumble across a problem to report vulnerabilities anonymously through an approved person (e.g., a staff member or faculty) and mechanism. Why anonymously? Because student vulnerability reporters are akin to whistleblowers. They are quite vulnerable to retaliation from the administrators of web sites (especially if it's a faculty web site that is used for grading). In addition, student vulnerability reporters need to be protected from the previously described situation, where they can become suspects and possibly unjustly accused simply because someone else exploited the web site around the same time that they reported the problem. Unlike security professionals, they do not understand the risks they take by reporting vulnerabilities (several security professionals don't yet either). They may try to confirm that a web site is actually vulnerable by creating an exploit, without ill intentions. Students can be guided to avoid those mistakes by having a resource person to help them report vulnerabilities. So, as a stubborn idealist I clashed with the detective by refusing to identify the student who had originally found the problem. I knew the student enough to vouch for him, and I knew that the vulnerability we found could not have been the one that was exploited. I was quickly threatened with the possibility of court orders, and the number of felony counts in the incident was brandished as justification for revealing the name of the student. My superiors also requested that I cooperate with the detective. Was this worth losing my job? Was this worth the hassle of responding to court orders, subpoenas, and possibly having my computers (work and personal) seized? Thankfully, the student bravely decided to step forward and defused the situation. As a consequence of that experience, I intend to provide the following instructions to students (until something changes):

1. If you find strange behaviors that may indicate that a web site is vulnerable, don't try to confirm if it's actually vulnerable.
2. Try to avoid using that system as much as is reasonable.
3. Don't tell anyone (including me), don't try to impress anyone, don't brag that you're smart because you found an issue, and don't make innuendos. However much I wish I could, I can't keep your anonymity and protect you from police questioning (where you may incriminate yourself), a police investigation gone awry and miscarriages of justice. We all want to do the right thing, and help people we perceive as in danger. However, you shouldn't help when it puts you at the same or greater risk. The risk of being accused of felonies and having to defend yourself in court (as if you had the money to hire a lawyer -- you're a student!) is just too high. Moreover, this is a web site, an application; real people are not in physical danger. Forget about it.
4. Delete any evidence that you knew about this problem. You are not responsible for that web site, it's not your problem -- you have no reason to keep any such evidence. Go on with your life.
5. If you decide to report it against my advice, don't tell or ask me anything about it. I've exhausted my limited pool of bravery -- as other people would put it, I've experienced a chilling effect. Despite the possible benefits to the university and society at large, I'm intimidated by the possible consequences to my career, bank account and sanity. I agree with HD Moore, as far as production web sites are concerned: "There is no way to report a vulnerability safely".

Edit (5/24/06): Most of the comments below are interesting, and I'm glad you took the time to respond. After an email exchange with CERT/CC, I believe that they can genuinely help by shielding you from having to answer questions from and directly deal with law enforcement, as well as from the pressures of an employer. There is a limit to the protection that they can provide, and past that limit you may be in trouble, but it is a valuable service.