--- title: "umdctf2024 - Donations" date: 2024-04-28T18:57:47-03:00 draft: false description: "" tags: ["web", "ctf"] --- After downloading and prettifying the javascript code we see that there's a `/api/flag` and a `/api/donate` endpoints. The flag route returns: ```json {"detail":"only the wealthy may view the treasure..."} ``` After trying some things that didn't work, I went to the donate functionality. Using the parameters that I found in the javascript I is playing with this funcionality and noticed that you can only donate to a specific user ```json {"detail":"you may only donate to Jeff Bezos"} ``` And somehow that Jeff Bezos's id is `lisanalgaib` The solution was to donate a negative amount and earn that in return. ```http POST /api/donate HTTP/2 Host: donations-api.challs.umdctf.io Content-Length: 30 Cookie: session=... Content-Type: application/x-www-form-urlencoded to=lisanalgaib¤cy=-99999 ```