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by jgrahamc 1908 days ago
You can start here: https://www.youtube.com/watch?v=nlt4XKhucS4
2 comments

Couple of points from the video:

1. The regular expression simplifier (https://youtu.be/nlt4XKhucS4?t=1102) stood out as particularly interesting - I get the impression it was partly "mostly simple", and partly battle-tested/nontrivial/hand-tuned. Speaking not-entirely-rhetorically, this would probably be a very interesting tidbit to study.

2. You mentioned at https://youtu.be/nlt4XKhucS4?t=2272 in response to a question that you apparently pass PNGs and other binary content "straight through" (in the context of file upload), ie bypassing the WAF. Given things like...

- webpage in JPEG (http://lcamtuf.coredump.cx/squirrel/, https://news.ycombinator.com/item?id=12262470, https://news.ycombinator.com/item?id=4209052),

- JavaScript in EXIF (https://blog.sucuri.net/2013/07/malware-hidden-inside-jpg-ex...)

- PHP in EXIF (https://web.archive.org/web/20130708132109/https://websec.io...)

- HTML+JavaScript+1021 byte demo inside PNG: https://news.ycombinator.com/item?id=24824299, http://www.p01.org/MONOSPACE/ (general NB: "Packed version" link under "Additional links" actually loads the demo for me in Chrome, but clicking through from HN and loading the URL directly doesn't - some sort of bizarre CORS-related thing?)

...I presume the status quo has changed somewhat here. Hearing how/what's going on in this space would be very interesting.

Slides: https://github.com/cloudflare/jgc-talks/raw/master/nginx.con...

Above link is direct download, which I'm biased towards since Chrome's PDF viewer supports left and right arrow keys.

Protip for users with tiny* screens: right-click video twice, enable Picture-in-Picture, arrange video so slides are still visible so you can follow along)

(* Specifically <24", ie laptops)