Is there any way I can report the ringleader (i.e. anonymously) without risking my own job?

So my understanding is that a lot of people are upset, and you know who the main person is that is telling others to retaliate. You want to disclose to your company who that person is so they can assign appropriate discipline.

Personally I think the issue is you have nothing to do with the issue other than being a spectator of it. My thought is as a spectator, nobody likes a tattle-tale because you're doing this out of spite, not because the person is actually doing anything that raises an legitimate ethical/moral/legal concern. By telling your HR that you know who the ringleader is, HR will ALWAYS side with the company. They will get rid of everyone involved, that includes you, the whistleblower. I should also mention that should someone find out, that might jeopardize your future job prospects because those people might be your boss or might be in a position to have a say in your hiring.

So overall I would say no. Do not bring it up or mention it unless the individuals are actively sabotaging the company and doing something illegal or ethically wrong.

I know who one of the ringleaders is (can prove it, but discovered it by doing something I shouldn't with the company network, which could get me fired if I admitted to doing it).

Whoa.... stop exactly now: "I shouldn't be doing with the company network". So how do you you know that you can prove it? Did you already do what you should not be doing or are you speculating? It is very possible that you already broke some law (and not just company policy) by doing what you did - ask a lawyer to be sure. Revealing gender and title of that co-worker could also get you in trouble if this post somehow make the way to your company.

Do not put yourself at risk for "obtaining proof", that is (I suppose) not your job. There are people whose job it may be, but they never would need to ask it here.

And how do you know about salary or agreements? To people like you around me, especially in economically troubled times I always indicated a "low" salary increase (without numbers) with a neutral or sad face when I actually knew that I got the biggest salary increase in the team.

or her team, but she doesn't get a pay raise or benefits increase, not even a new title she can use on her resume/CV or LinkedIn profile to help her get a higher-paying job at a different company or competitor.

You exhibit a certain mindset in your post, and I see a good possibility that you project it to your co-worker. The motives you suppose that hold for others "to even a new title ... to help her get a higher-paying job" in combination with your "want to continue to rise up the ranks of this company." and interpretation of professional relationships in terms of loyalty show your mindset. I know that it may take some time until you get what I want to say, but that's that.

Now let's go to what you should do: if you have the impression that the company is not aware of this, then inform them about things which you can know for sure:

• Boss, I recently saw weird message on a linkedin profile - is that really our HR?
• Boss, which titles can I use on my linkedin profile - I recently saw a lot of people updating and wondered if I missed something
• If your trust your Boss: Hi, have you recently seen the people update their linkedin profiles. Is anything going on about which I should know?

Most important: Face it- your management decided whom to promote. What management did tell/promise them or not is speculation. It could be that the "ring leader" will be your new boss - if the company survives. It could be another envious person of the promotion in the team trying to smear the person. It could be that the company is already dead and the new titles were given to the persons relevant to polishing up the IP for sale. It could be that you are (independently of anything which you could do) on the list of people to be fired. It could be that the "ring leader" decided to leave the company and as a kind of friendly agreements new titles were given and the person helps a good transition.

The Company has made a mistake that set them down this path. Outing the 'ringleader' of the prank isn't going to avert the disaster the company started by messing their employees around.

All you'll do is side with a company that is going to be struggling soon and may be looking to cut costs. Someone who admits to having done something they shouldn't have with the company network can probably be let go without that costly severance package. You'll be a prime target for cost cutting.

I'm really not sure what you hope to achieve.

I am sure this prank caused plenty of drama within your company. However I think you might be vastly overestimating the amount of attention it received outside your company. Don't think that many people outside your company pay that much attention to the LinkedIn profiles of your colleagues. So I think it's very unlikely that such a prank really endangers your company and there is no need for you to "save" the company by exposing it's ringleader.

So like the other answers I think the best thing you can do is stay out of it, especially since you got the evidence by doing unsavory things yourself.

Company is getting exactly what they deserve. 25+ senior engineers, in other words highly experienced and highly intelligent people, are showing the company that they are pissed off. There are two outcomes: Either the company will do something significantly to placate them (firing the one person in management responsible for the mess would free up enough money to give everyone a four percent rise), or these 25+ engineers will very soon be gone to better jobs.

If you think you should get involved in this, you are most likely to end up under a steamroller.

No, mind your own business.

There is very little upside to being embroiled in the drama even as a “whistleblower”. There are a lot of ways for it to make trouble for you and frankly the “chaos” of people changing their social media profiles is not going to hurt anything.

Best case you please some manager or HR person and earn the undying enmity of all the actual engineers which you may be working for or with for a lot of your career. And if they all hate and mistrust you as being a snitch you are poisoning your career.

Worst case is you get fired for cause for network snooping on employees. Given what is going on, the managers have a lot more to hide and will be more worried about what you could do than the “LinkedIn Mafia” will be. And nothing is better than a scapegoat you can legally fire for cause to try to scare the others back into line.

Your current work environment is toxic, but it’s the fault of the management being unprofessional towards the staff, not the fault of the oppressed staff acting up a bit. You shouldn’t put up with being exploited nor should you contribute to the exploitation of your peers.