Hacker News new | ask | show | jobs
by praptak 25 days ago
Appending stuff to bypass blacklists is eternal.

My first job, decades ago. I couldn't update something on my laptop because client's gateway blocked `http://foo.com/update.exe`. Guess what, `http://foo.com/update.exe?` worked as a bypass.

2 comments

A DPI firewall at a place of education had a whitelist of allowed domains that you could connect to from the internal network. One entry in the whitelist was "microsoft.com".

I installed a web proxy on my VPS, which was accessible under a domain name like "computerthings.example", created a subdomain called "microsoft", and voila: "microsoft.computerthings.example" was good enough to match "^microsoft.com.*" and allowed us to bypass the block for the next two years.

Ah, a rare situation where you have to put your URL in angle brackets for it to be parsed correctly here: <http://foo.com/update.exe?> (Not that it matters in this case. Also I would’ve guessed the angle brackets would disappear, but apparently not.)

[1] https://news.ycombinator.com/formatdoc