I scanned a site using a vulnerability scanner and it found a vulnerability with a CVV score of 10. Should I send the report to the company?

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    Why wouldn't you report? What's the source of your question?
    – schroeder
    Commented Nov 8, 2019 at 17:13
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    Report it as opposed to what - hacking it? Commented Nov 8, 2019 at 17:38
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    As a n0ob - I think the alternative to reporting it would be not reporting it. This question heavily implies that the scan was done without prior authorization from the company. I'm not a lawyer and I'm not saying it's illegal, but I would be concerned about consequences for myself. I know for a fact my ISP (Xfinity) prohibits this activity and reserves the right to immediately suspend my account for violating it. There are local/state laws I might not be aware, and I do know companies could have a civil claim against you for damages as the result of a scan.
    – Rob P.
    Commented Nov 10, 2019 at 8:40
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    Possible duplicate of How to report vulnerabilities without being regarded as a hacker? Commented Nov 11, 2019 at 7:53
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    @ConorMancone All I see in the edits is "I haven't hacked it"--but that mostly doesn't matter! As other answers have pointed out, if you did not have permission to scan/test that site, you probably already broke the law. If the company is mad about you checking up on them, they can potentially cause real trouble for you. Commented Nov 11, 2019 at 17:05

3 Answers 3


Quick note: this answer assumes that you have permission to run scanners against the website. Running scanners against a website is illegal in basically all jurisdictions, so if you are doing that then my only suggestion is: "STOP!".

What you shouldn't do

You should never send a vulnerability report from a scanner to a company. 90% of the time those are useless by themselves, and are likely to be ignored by any competent security team. The reason is because scanners can have any number of false positives, so a positive from a vulnerability scanner does not actually mean there is a vulnerability. However, it is common for new bug bounty testers to simply send vulnerability reports from scanners off to companies without any understanding of what the report says, if it is correct, or if it is even applicable. As a result security teams will often just ignore a report that came straight out of a scanner. Most bug bounty programs specifically state this.

What you should do

Instead you should take the time to generate a vulnerability report yourself, which means that you describe the nature of the vulnerability, steps they can take to confirm your findings, the risk the vulnerability creates for the company, and potentially even steps they can take to mitigate the danger. That is what you should send to the company, and sending something like that is almost always a good idea.

If this is a company that doesn't have a public bug bounty program then they are even less likely to be able to make sense of a report out of a scanner, so it will be that much more important for you to take the time and provide an actually vulnerability report detailing the vulnerability, the impact to the business, an estimate of its severity, and suggested mitigation steps. Obviously though that's not the situation you are in, since running automated security scans on a website without explicit approval is illegal in most jurisdictions and a bad idea in general...


Should you send the results from your scanner to a company? No, because that's often useless. What you should do is verify that the scanner isn't reporting a false positive and then send a report detailing the vulnerability, what they can do to reproduce it, an explanation of its impact, and suggested mitigation steps. You obviously shouldn't "hack" into the system under any circumstances.

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    I'm one of the security team members who receives random reports like this. I agree that 90% of the time it's a false positive sent by an amature sec researcher who has no idea what the finding means. That said, 10% of the time, it's a tool we don't run and it's useful. Also, 100% of the time it tells us about the PR impact of people scanning our site. We do sometimes make "unnecessary" code changes purely for PR reasons so that our customers get less alarmed when they run a scan. Commented Nov 8, 2019 at 18:15
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    @MikeOunsworth I went ahead and updated my question to better emphasize my actual suggestion, which is sending a detailed vulnerability report instead of a report from the scanner. Although in doing so the organization of my answer now more closely mirrors yours. :shrug: Commented Nov 8, 2019 at 18:35
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    @user1067003 I don't really agree. Expecting to scan sites without permission would be like walking down the street trying to open people's front doors. Then when someone calls the police and they show up you reply with, "I'm just checking to make sure that people locked their doors" and expecting the police to be happy with it. It's a terrible idea. Commented Nov 10, 2019 at 12:44
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    @ConorMancone Please include your last comment in the body of the question, because it's relevant: the question implies that the OP has not contacted the company, and therefore does not have permission.
    – jpaugh
    Commented Nov 10, 2019 at 23:33
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    @jpaugh I already had mention of that in my answer, although obviously it wasn't obvious enough. I've put up a small update accordingly. Commented Nov 11, 2019 at 13:13

Rule one of vulnerability scanning or any other activity that could possibly be interpreted as hostile: get permission in writing signed by senior management first. An unsolicited "vulnerability scan" is indistinguishable from a hacking attempt - and if you used a common tool, and they have any smart monitoring going on, they will have detected that scan, and logged your IP address. And a poorly-worded report of a vulnerability you have found is indistinguishable from a threat. If you're lucky, the existence of a common bug in their site might mean they don't have good monitoring. However such a company is more likely to call the police if they think, however incorrectly, that you are threatening to hack them.

Consider it this way: a random stranger one day tells you that you left your windows unlocked. He or she swears that they didn't go into your house. Would you be grateful or would you wonder why this person was trying your windows?

It is sad to say but this is the reality of the world today - your most sensible option is to do nothing. Consider that you have learned something about vulnerability scanning today, and move on.

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    +1 for the only answer questioning the scanning. Commented Nov 9, 2019 at 12:17
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    +1 to this. I know someone who ran a vulnerability scanner against a small website just to see what would happen and it destroyed the website. It found a whole load of vulnerabilities but also wrecked the database and the website wouldn't load anymore. Be very, very careful. Nobody should be running vulnerability scans without permission.
    – niemiro
    Commented Nov 9, 2019 at 15:30
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    Another +1. Every time I read about someone running a vulnerability scan on some site (not owned by that person), it strikes me as why the hell do they even think they're entitled to do so. It's like using a crowbar on someone's front door only to verify whether it's burglary-resistant. Surely, nobody would have the idea that this is legitimate in the real world.
    – Damon
    Commented Nov 9, 2019 at 20:28
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    Yes, it is way too risky to report it. Just ask one of the authors of the famous book Programming Perl. Commented Nov 9, 2019 at 21:19
  • Would you be grateful or would you wonder why the person was trying your windows? — the answer probably says a lot about local culture.
    – gerrit
    Commented Nov 11, 2019 at 12:35

Do you want to be a white-hat or black-hat? The answer may also depend on what laws apply based on what country you are in, what country the company is in.

Things that are always ok

Use a responsible disclosure process to disclose the finding to the company.

See if the company has a vulnerability reporting process. A good place to start is seeing if they have a https://company.com/.well-known/security.txt. If not then search around and see if they have a security email address for reporting things like this.

Another option if you can't or don't want to deal with the company directly is to report through a middle-man like US Cert.

It should also be stated here that if you want the company to take you seriously, you need to clearly describe the issue, steps to reproduce, describe how pervasive it is in their application, what damage and attacker could cause with it, and what they should do to fix it. If you just send them the report from a scanner, they will likely ignore you, or worse send a lawyer after you (see below).

Things that are sometimes ok

Sometimes it's ok to publish the result without informing the company (for example by filing a CVE, or writing a blog post, github repo).

Depending on the type and severity of the vulnerability, this could end up doing more damage than good if people get hacked before the company has time to fix it.

"Things that are sometimes ok" could include running the scanner in the first place. Unless you are hired to do that or there's a bug bounty program, it could be interpreted as a hacking attempt. (Thanks @EsaJokinen). A quick google-search shows that when you do "security research" without permission you're just as likely get lead to jail time, as to get a thank you:

Hitting someone else's website with a security scanner can land you in big trouble, so make sure you understand the legal implications before you do it!

Things that are never ok

Hacking the website yourself.

This is undoubtedly illegal in every country that has laws about this.

Be very careful taking this approach because you can lose a lot, and I'm not sure you gain anything (at least from a white-hat perspective).

  • This is the first time I've heard of US Cert. If you have time, would you mind joining me in chat so I can ask you a question about it? Obviously no big deal if you can't Commented Nov 8, 2019 at 18:37
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    @ConorMancone Which chat channel? I don't know a ton about US CERT, except that they will act as an intermediary where a researcher is too small to get noticed, wants to maintain anonymity, or the researcher feels they will be legally intimidated by the vendor. From the linked site: "CISA will attempt to coordinate all reported cyber vulnerabilities with the affected vendor of industrial control systems or information technology products." Commented Nov 8, 2019 at 19:07
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    "Things that are sometimes ok" could include running the scanner in the first place. Unless you are hired to do that or there's a bug bounty program, it could be interpreted as a hacking attempt. Commented Nov 9, 2019 at 11:34
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    This is the first time I've heard of .well-known. Ironic, isn't it?
    – CJ Dennis
    Commented Nov 10, 2019 at 0:49
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    @ConorMancone the national CERT will care about that, enough to forward the report to the proper recipient. In case it wasn't a US company, I would recommend contacting instead the respective national CERT (you can find most of them on FIRST), but other than that, a working CERT that receives a proper report for a company under their constituency, will (attempt to) report it to the affected party. It is their job!
    – Ángel
    Commented Nov 12, 2019 at 0:21

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