Firefox: Blocked connection: potential security issue

Solved
PatrickKelkonk Posted messages 11 Status Membre -  
MisteryBean Posted messages 8946 Registration date   Status Modérateur Last intervention   -
Hello, I have been using Firefox for years, but a few days ago I decided to format my PC to give it a fresh start. The formatting went well, I reinstalled everything, and Firefox was working perfectly. But one fine morning, disaster struck! While trying to watch a little YouTube video, this error message appeared:

"Firefox has detected a potential security threat and has stopped loading www.youtube.com because this website requires a secure connection.

What can you do?

www.youtube.com uses a HTTP Strict Transport Security (HSTS) policy, a secure connection is mandatory to access it. You cannot add an exception to visit this site.

The problem likely comes from the website, so you cannot fix it.

If you are browsing on a corporate network or using antivirus software, you can contact support teams for help. You can also report the problem to the people who administer the website."

I cannot ignore the error message and go to YouTube. I then went to Mozilla support to seek help. Unfortunately, their support system (which I find dreadful) mostly wasted my time. So I thought, naively, "Well, I might as well contact support directly." To my surprise, I found that there was NO way to contact them, and they suggested going to a forum. Hence this message.

Thank you for your attention, hoping you are more competent than Mozilla.

20 réponses

MisteryBean Posted messages 8946 Registration date   Status Modérateur Last intervention   1 291
 
Hello,

Does it work with another browser? (like Edge for example)

In Firefox, click on the three lines at the top right => Help => Troubleshooting Mode => Restart.
Try going to YouTube. If it works, it means that it's an extension causing the problem.
You will need to disable them and test one by one.

--
Security contributor.
0
PatrickKelkonk Posted messages 11 Status Membre
 
Other browsers work, I "repaired" Firefox, without success, and I uninstalled/reinstalled it without success either.
0
MisteryBean Posted messages 8946 Registration date   Status Modérateur Last intervention   1 291
 
After repairing, did you no longer have any extensions?

Try what I indicated anyway

--
Security contributor.
0
PatrickKelkonk Posted messages 11 Status Membre
 
I tried what you told me, unfortunately still without success.
0
MisteryBean Posted messages 8946 Registration date   Status Modérateur Last intervention   1 291
 


=> Press Windows + R
=> Type firefox -p and press enter
=> Click on Create Profile
=> Give it a random name
=> Click on the created profile and start Firefox

What does that give?

0
PatrickKelkonk Posted messages 11 Status Membre
 
Firefox starts but there is still an error message.
0
MisteryBean Posted messages 8946 Registration date   Status Modérateur Last intervention   1 291
 
Are you doing well with the created profile? Firefox empty like a fresh installation?

What antivirus do you have?

0
PatrickKelkonk Posted messages 11 Status Membre
 
Yes, Firefox is like I've just installed it and my only antivirus is Windows Defender.
0
MisteryBean Posted messages 8946 Registration date   Status Modérateur Last intervention   1 291
 
Do you have this problem only on YouTube?

Are you signed in to YouTube? Or Google?

--
Security contributor.
0
PatrickKelkonk Posted messages 11 Status Membre
 
The problem is with YouTube and Google, and yes, I was logged in with my Google account.
0
MisteryBean Posted messages 8946 Registration date   Status Modérateur Last intervention   1 291
 
Normally, with the new profile, you shouldn't be logged into Google, can you confirm?

If you click on https://www.youtube.com/ from Firefox, is it the same?

--
Security contributor.
0
PatrickKelkonk Posted messages 11 Status Membre
 
No, with the new profile I have no more extensions, I'm more connected, Firefox is clean, even going through the link it doesn't work.
0
MisteryBean Posted messages 8946 Registration date   Status Modérateur Last intervention   1 291
 
It's really strange. On my PC under Firefox, it's working perfectly :-(

Are the other Google apps working? Gmail / drive / etc .. ?

We can try to run a diagnostic on the PC:

Read the entire procedure before posting the reports
Do not post them directly in the messages as they are unreadable and incomplete

The reports FRST.txt and Addition.txt are expected

All reports must be hosted on https://security-x.fr/up/ and you must include the obtained links in your response

---------------------------------------------------------------------------------------------

--> The SmartScreen filter may trigger an alert. Click on Actions or More info and then click on Run anyway

---------------------------------------------------------------------------------------------

--> Download the FRST version of Farbar, compatible with your system, and save the file on your Desktop

--> For a 32-bit system
--> For a 64-bit system

How to know which version 32 bits or 64 bits is running on my system?

--> Wait for your browser to offer the download to save, without clicking anywhere, especially not on the page sponsors.
--> Close all applications, including your browser
--> Double-click on FRST.exe and click Yes to accept the Disclaimer
--> Under Vista, Windows 7 / 8 and 10, you must launch the file by right-clicking -> Run as administrator
--> Wait for it to say The tool is ready to run
--> On the main menu, click on Scan and wait for the scan to complete
--> At the end of the scan, the FRST.txt and Addition.txt reports are created. Post these reports in your next response.
--> The reports are saved in the same location as the tool and under C:\FRST\Logs

--
Security contributor.
0
PatrickKelkonk Posted messages 11 Status Membre
 
Addition : https://up.security-x.fr/file.php?h=R97bc88e535656a167f55ef96e5b04bd7

FRST : https://up.security-x.fr/file.php?h=R5002735c07d8e16a0d3bf7d079fd42f6
0
MisteryBean Posted messages 8946 Registration date   Status Modérateur Last intervention   1 291
 
RE_

Windows Defender blocked the Windows crack you tried to install.

KMS installed a proxy, which might be what Firefox is detecting.

KMS often comes with a trojan and/or a proxy, so with licenses available for 1 euro, it’s not worth getting infected.

We can clean up the PC, and then you'll need to get legal.

HKLM\SOFTWARE\Policies\Microsoft\Windows\CurrentVersion\Internet Settings: [ProxySettingsPerUser] 0 <==== WARNING (Restriction - ProxySettings)
AutoConfigURL: [HKLM] => hxxp://127.0.0.1:86/
AutoConfigURL: [HKLM-x32] => hxxp://127.0.0.1:86/
AutoConfigURL: [{B8945291-0F69-4927-B89A-5BC3DDC6169D}] => hxxp://127.0.0.1:86/
Tcpip\Parameters: [DhcpNameServer] 192.168.1.1
Tcpip\..\Interfaces\{af81a7ca-993d-4b68-bef7-6937bd7440c4}: [DhcpNameServer] 192.168.42.129
Tcpip\..\Interfaces\{c5a7ca8c-3b57-4f80-8119-b0231db7f7b7}: [DhcpNameServer] 192.168.1.1
ManualProxies: 0hxxp://127.0.0.1:86/
HKLM\SOFTWARE\Policies\Microsoft\Internet Explorer: Restriction <==== WARNING


0
PatrickKelkonk Posted messages 11 Status Membre
 
I have been using KMS for years and here is the famous downside that I was told about so much...

Ugh, I guess I will buy Windows then.

Thank you very much anyway and have a good evening.
0
MisteryBean Posted messages 8946 Registration date   Status Modérateur Last intervention   1 291
 
RE_

Do you want me to provide a fix to remove KMS and what it has installed? This will help verify if that's what is blocking YouTube and you can get into compliance more easily.

--
Security contributor.
0
PatrickKelkonk Posted messages 11 Status Membre
 
No, don't worry, I can handle this part; I've been using it for a long time and I've never had any problems, I didn't think it would come from there.

But thank you very much!
0
PatrickKelkonk Posted messages 11 Status Membre
 
PS: I just deleted KMS and everything is working again!!
0
MisteryBean Posted messages 8946 Registration date   Status Modérateur Last intervention   1 291
 
OK, all that’s left is to buy a key ;-)

Wishing you the best

--
Security contributor.
0