[Outages-discussion] paypal.com certificate revoked?

[Fabian Wenk]

Hello William

On 15.10.2022 01:18, William Kern via Outages-discussion wrote:
> yes, I was wondering about that. If you 0wned paypal.com but not
> www.paypal.com you could redirect them somewhere nasty.

Sure, something like this could be, but it is probably not the case in 
what we see.

 From my location paypal.com does resolve to two IP addresses (only 
IPv4, no IPv6 AAAA entry):

% dig -t a paypal.com

; <<>> DiG 9.18.7 <<>> -t a paypal.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 34200
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
; COOKIE: 3d4e80718edbaf1201000000634a7bd2080314135694247b (good)
;; QUESTION SECTION:
;paypal.com.			IN	A

;; ANSWER SECTION:
paypal.com.		266	IN	A	64.4.250.36
paypal.com.		266	IN	A	64.4.250.37

;; Query time: 0 msec
;; SERVER: ::1#53(::1) (UDP)
;; WHEN: Sat Oct 15 11:22:26 CEST 2022
;; MSG SIZE  rcvd: 99


And www.paypal.com to an IP address from Fastly (IPv4 only as well):

% dig -t a www.paypal.com

; <<>> DiG 9.18.7 <<>> -t a www.paypal.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 37683
;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
; COOKIE: fd4fee988a34d76801000000634a7c8d75824b434a27dbf6 (good)
;; QUESTION SECTION:
;www.paypal.com.			IN	A

;; ANSWER SECTION:
www.paypal.com.		3384	IN	CNAME	www.glb.paypal.com.
www.glb.paypal.com.	85	IN	CNAME	www-fastly.glb.paypal.com.
www-fastly.glb.paypal.com. 85	IN	A	151.101.65.21

;; Query time: 2 msec
;; SERVER: ::1#53(::1) (UDP)
;; WHEN: Sat Oct 15 11:25:33 CEST 2022
;; MSG SIZE  rcvd: 144


> Paypal actually has two redirects on the site.
> 
> http://paypal.com goes to https://paypal.com (which then goes to
> https://www.paypal.com)

This is the proper way in doing a redirect from a domain only (without 
www) from HTTP to the hostname (with www) with HTTPS. The idea is, that 
on the HTTPS site (e.g. just paypal.com) the Strict-Transport-Security 
Header is set and so the browser can be made aware of, that this site 
should be visited with HTTPS. On the next visit, even if the user just 
types paypal.com into the URL bar, the browser goes directly to 
https://paypal.com/ and so with only encrypted communication.

> $ curl -I http://paypal.com
> HTTP/1.1 301 Moved Permanently
> Content-Type: text/html
> Content-Length: 185
> Connection: keep-alive
> Location: https://paypal.com/
> 
> so that may play a role.
> 

Sure it does, but as mention above it is the proper way in doing it.

When I test this two IP addresses with openssl s_client -status, I do 
not get an OCSP Stapling response, as it may have expired now. Probably 
they are not aware of the problem yet, as even on Firefox the OCSP check 
may not be enabled. The revoke reason 'superseded' suggests that they 
may have a new certificate, but it has not been deployed yet. Somebody 
at PayPal may now have a busy weekend in figuring out what went wrong.


Best regards,
Fabian