If your bug bounty program is private, why do you have it?

The big bug bounty platforms are structured like icebergs: the public bug bounty programs that you can see are only a tiny portion of everything that is going on there. As you earn your reputation on these platforms, they will be inviting you to private bug bounty programs. The catch: you generally aren’t allowed to discuss issues reported via private bug bounty programs. In fact, you are not even allowed to discuss the very existence of that bug bounty program.

I’ve been playing along for a while on Bugcrowd and Hackerone and submitted a number of vulnerability reports to private bug bounty programs. As a result, I became convinced that these private bug bounty programs are good for the bottom line of the bug bounty platforms, but otherwise their impact is harmful. I’ll try to explain here.

What is a bug bounty?

When you collect a bug bounty, that’s not because you work for a vendor. There is no written contract that states your rights and obligations. In its original form, you simply stumble upon a security vulnerability in a product and you decide to do the right thing: you inform the vendor. In turn, the vendor gives you the bug bounty as a token of their appreciation. It could be a monetary value but also some swag or an entry in the Hall of Fame.

Why pay you when the vendor has no obligation to do so? Primarily to keep you doing the right thing. Some vulnerabilities could be turned into money on the black market. Some could be used to steal data or extort the vendor. Everybody prefers people to earn their compensation in a legal way. Hence bug bounties.

What the bug bounty isn’t

There are so many bug bounty programs around today that many people made them their main source of income. While there are various reasons for that, one thing should not be forgotten: there is no law guaranteeing that you will be paid fairly. No contract means that your reward is completely dependent on the vendor. And it is hard to know in advance, sometimes the vendor will claim that they cannot reproduce, or downplay severity, or mark your report as a duplicate of a barely related report. In at least some cases there appears to be intent behind this behavior, the vendor trying to fit the bug bounty program into a certain budget regardless of the volume of the reports. So any security researcher trying to make a living from bug bounties has to calculate pessimistically, e.g. expecting that only one out of five reports will get a decent reward.

On the vendor’s side, there is a clear desire for the bug bounty program to replace penetration tests. Bugcrowd noticed this trend and is tooting their bug bounty programs as the “next gen pen test.” The trouble is, bug bounty hunters are only paid for bugs where they can demonstrate impact. They have no incentives to report minor issues, not only will the effort of demonstrating the issue be too high for the expected reward, it also reduces their rating on the bug bounty platform. They have no incentives to point out structural weaknesses, because these reports will be closed as “informational” without demonstrated impact. They often have no incentives to go for the more obscure parts of the product, these require more time to get familiar with but won’t necessarily result in critical bugs being discovered. In short, a “penetration test” performed by bug bounty hunters will be everything but thorough.

How are private bug bounties different for researchers?

If you feel that you are treated unfairly by the vendor, you have essentially two options. You can just accept it and vote with your feet: move on to another bug bounty program and learn how to recognize programs that are better avoided. The vendor won’t care as there will be plenty of others coming their way. Or you can make a fuzz about it. You could try to argue and probably escalate to the bug bounty platform vendor, but IMHO this rarely changes anything. Or you could publicly shame the vendor for their behavior and warn others.

The latter is made impossible by the conditions to participate in private bug bounty programs. Both Bugcrowd and Hackerone disallow you from talking about your experience with the program. Bug bounty hunters are always dependent on the good will of the vendor, but with private bug bounties it is considerably worse.

But it’s not only that. Usually, security researchers want recognition for their findings. Hackerone even has a process for disclosing vulnerability reports once the issue has been fixed. Public Bugcrowd programs also usually provision for coordinated disclosure. This gives the reporters the deserved recognition and allows everybody else to learn. But guess what: with private bug bounty programs, disclosure is always forbidden.

Why will people participate in private bug bounties at all? Main reason seems to be the reduced competition, finding unique issues is easier. In particular, when you join in the early days of a private bug bounty program, you have a good opportunity to generate cash with low hanging fruit.

Why do companies prefer private bug bounties?

If a bug bounty is about rewarding a random researcher who found a vulnerability in the product, how does a private bug bounty program make sense then? After all, it is like an exclusive club and unlikely to include the researcher in question. In fact, that researcher is unlikely to know about the bug bounty program, so they won’t have this incentive to do the right thing.

But the obvious answer is: the bug bounty platforms aren’t actually selling bug bounty management, they are selling penetration tests. They promise vendors to deliver high-quality reports from selected hackers instead of the usual noise that a public bug bounty program has to deal with. And that’s what many companies expect (but don’t receive) when they create a private bug bounty.

There is another explanation that seems to match many companies. These companies know perfectly well that they just aren’t ready for it yet. Sometimes they simply don’t have the necessary in-house expertise to write secure code, so even with they bug bounty program always pointing out the same mistakes they will keep repeating them. Or they won’t free up developers from feature work to tackle security issues, so every year they will fix five issues that seem particularly severe but leave all the others untouched. So they go for a private bug bounty program because doing the same thing in public would be disastrous for their PR. And they hope that this bug bounty program will somehow make their product more secure. Except it doesn’t.

On Hackerone I also see another mysterious category: private bug bounty programs with zero activity. So somebody went through the trouble of setting up a bug bounty program but failed to make it attractive to researchers. Either it offers no rewards, or it expects people to buy some hardware that they are unlikely to own already, or the description of the program is impossible to decipher. Just now I’ve been invited to a private bug bounty program where the company’s homepage was completely broken, and I still don’t really understand what they are doing. I suspect that these bug bounty programs are another example of features that somebody got a really nice bonus for but nobody cared putting any thought into.

Somebody told me that their company went with a private bug bounty because they work with selected researchers only. So it isn’t actually a bug bounty program but really a way to manage communication with that group. I hope that they still have some other way to engage with researchers outside that elite group, even if it doesn’t involve monetary rewards for reported vulnerabilities.


As a security researcher, I’ve collected plenty of bad experiences with private bug bounty programs, and I know that other people did as well. Let’s face it: the majority of private bug bounty programs shouldn’t have existed in the first place. They don’t really make the products in question more secure, and they increase frustration among security researchers. And while some people manage to benefit financially from these programs, others are bound to waste their time on them. The confidentiality clauses of these programs substantially weaken the position of the bug bounty hunters, which isn’t too strong to start with. These clauses are also an obstacle to learning on both sides, ideally security issues should always be publicized once fixed.

Now the ones who should do something to improve this situations are the bug bounty platforms. However, I realize that they have little incentive to change this situation and are in fact actively embracing it. So while one can ask for example for a way to comment on private bug bounty programs so that newcomers can learn from the experience that others made with this program, such control mechanisms are unlikely to materialize. Publishing anonymized reports from private bug bounty programs would also be nice and just as unlikely. I wonder whether the solution is to add such features via a browser extension and whether it would gain sufficient traction then.

But really, private bug bounty programs are usually a bad idea. Most companies doing that right now should either switch to a public bug bounty or just drop their bug bounty program altogether. Katie Moussouris is already very busy convincing companies to drop bug bounty programs they cannot make use of, please help her and join that effort.


There are currently no comments on this article.