WhatsApp follows your links
This is not a secret, but I found it curious and thought about sharing it here: earlier today I needed to share a video file that I was hosting in my server, and I decided to send the link over WhatsApp. As I was looking at the log files at the time, I managed to catch this curious set of requests:
7c0h.com:443 203.0.113.19 - - [14/Nov/2019:20:02:49 +0100] "GET / HTTP/1.1" 200 5059 "-" "WhatsApp/2.19.305 A"
7c0h.com:443 203.0.113.19 - - [14/Nov/2019:20:02:51 +0100] "GET / HTTP/1.1" 200 1806 "-" "WhatsApp/2.19.305 A"
7c0h.com:443 203.0.113.19 - - [14/Nov/2019:20:02:53 +0100] "GET /fi HTTP/1.1" 404 549 "-" "WhatsApp/2.19.305 A"
7c0h.com:443 203.0.113.19 - - [14/Nov/2019:20:02:53 +0100] "GET /fil HTTP/1.1" 404 688 "-" "WhatsApp/2.19.305 A"
7c0h.com:443 203.0.113.19 - - [14/Nov/2019:20:02:54 +0100] "GET /file HTTP/1.1" 404 689 "-" "WhatsApp/2.19.305 A"
7c0h.com:443 203.0.113.19 - - [14/Nov/2019:20:02:54 +0100] "GET /files HTTP/1.1" 404 690 "-" "WhatsApp/2.19.305 A"
7c0h.com:443 203.0.113.19 - - [14/Nov/2019:20:02:55 +0100] "GET /files3 HTTP/1.1" 404 691 "-" "WhatsApp/2.19.305 A"
7c0h.com:443 203.0.113.19 - - [14/Nov/2019:20:02:57 +0100] "GET /files3.mpr HTTP/1.1" 404 695 "-" "WhatsApp/2.19.305 A"
7c0h.com:443 203.0.113.19 - - [14/Nov/2019:20:03:00 +0100] "GET /files3.mp HTTP/1.1" 404 694 "-" "WhatsApp/2.19.305 A"
7c0h.com:443 203.0.113.19 - - [14/Nov/2019:20:03:01 +0100] "GET /files3.mp4 HTTP/1.1" 200 219785 "-" "WhatsApp/2.19.305 A"
In simple terms: ever since WhatsApp identified that I was sending a
link (that is, after I wrote https://7c0h.com/), WhatsApp generated a
new request for every letter I typed (including the "mpr" typo). It's a
good thing they only downloaded 215Kb of data too, because the request
came straight from my phone. I guess there is no reason to optimize your
code when you don't pay for the bandwidth.
