PayPal & HTTPS

[Darth Shiv]

The issue with the certificate is actually stated in the original "subject":

"pixel.mathtag.com"

That is the website the certificate is valid for. You are visiting a website called paypal.com. So the subject doesn't match I.e. the certificate was NOT for paypal. Could be a MITM attack.

Secondly, certificate trust chains NEED a domain name. NO certificate is valid for an IP address as the trust chain checks the certificate subject and validates it against the address you visit as well as the issuer of the certificate. It's like asking if the certificate is authentic. Anyone can say "oh yeah this is a paypal certificate" but the way it is verified is it is signed by an authority that is trustworthy to check the person who requested signing is the legit owner of the domain. So there is no way to bind an IP to a certificate and check validity because that is not how the system is designed to work.

The problem is clearly yours. Your machine has been compromised in some way. A *very unlikely* alternative is your ISP is trying a MITM attack.

 

[Cycloid Torus]

The problem is clearly yours. Your machine has been compromised in some way. A *very unlikely* alternative is your ISP is trying a MITM attack.

Totally agree. Have contacted ISP and described issue - they will check.

What I am looking at is like a database file which needs re-packing. I am seeing entries in the DNS where the IP is perfectly good, but for another name. I am also seeing differences between the local machine DNS and the Chrome DNS (can't get at FireFox as that is hidden for "privacy"). I reinstalled Chrome and changed Chrome DNS TTL to 1 second - and have had no problems since. This may be just a bandaid, so I appreciate any other thoughts.

 

[Darth Shiv]

Try setting your DNS to google's DNS servers
https://developers.google.com/speed/public-dns/
8.8.8.8 and 8.8.4.4.

 

[Darth Shiv]

Firefox probably using your local machine DNS settings - at a command prompt type "ipconfig /all" and look for your wired or wireless adapter in the output.

 

[Cycloid Torus]

Paypal indicated their recent 'upgrade' (no detail) might have been issue. I cleaned all in Chrome, uninstalled and re-installed. Problem seems fixed.

Thanks for helpful suggestions, all.