I just visited a forum and a member knew what OS I was running without me saying anything (a not TOO common distro of linux). Now I'm not sure how he exactly he might have done it, or what information he might have been able to get out, but, for starters, I'm guessing that, besides information on my OS, they might have been able to determine other things such as my ip address, general location, browser, and even browser cookies. Whether or not it was necessary, I deleted my browser, performed a scan with both chkrootkit and rkhunter, and will never get back on that site. Heck, I'm wondering if by posting here so soon after, I'm putting myself at risk.

I guess the questions burning in my mind are: can they pose a threat to others in my network assuming there is a firewall and wpa2 security type? I don't have any real important information in my system, and I don't really do anything that might really put me at real risk besides the odd online purchase, but I don't know what others might have in their systems.

Should I be able to keep doing those normally until I see something weird? Besides what I already mentioned, what other steps should someone in this situation take?

  • Was the member a moderator or admin? They often have extra access to user information that you provide to the server simply by visiting (e.g. IP), though I haven't heard of one that displays user agents. It's not normally displayed to normal users or those not logged in, though. – Someone Somewhere Mar 1 '16 at 22:42

I wouldn't be overly concerned. There are plenty of ways he could possibly have found your operating system, a lot of them not considered malicious and are done directly through the browser without any form of exploit.

For example this information could come from your user agent: http://en.wikipedia.org/wiki/User_agent

Through the user agent they could also get your browser configuration too. As you rightly say, they would definitely know your IP address, which could be geo-located to your city.

There is also a technique called fingerprinting, which can get things like your version of Java and other software which may run in your browser. Have a look at this link and click "Test Me" - you might be surprised!

In terms of getting onto your network, unless you know the site is running some form of malicious code which could take control of your machine, I would expect you are safe. In order to control your machine, it would need to break out of your browser and get local rights.

Typically this can only be done by exploiting a vulnerability in your browser or application software. The best mitigation for this is to ensure that your browser and any browser embedded software such as Java and Flash are up-to-date.


I think you can safely live normally ;)

The user in this forum propably just took a guess on your UserAgent. This is neither considered hacking nor does it do any damage on your pc. There is even a Website telling you what OS you use, only by visiting it. There are also more informations about how this is working.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.