challenge info  
Name: Celeste Speedrunning Association
Category: Web
Difficulty: Easy
Points: 20
Link:

 

 

Description

I love Celeste Speedrunning so much!!! It’s so funny to watch!!!

Here’s my favorite site!

Approach

Upon examining the Source Code, it appears that the website is utilizing a hidden input field called “start” that utilizes the Unix epoch time to verify the present time.

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Once the button is clicked, the server calculates the duration from the start time to when the request is received by the server. If the duration is less than 0 sec the flag will be displayed. However, this can only be accomplished by modifying the epoch value to a future time (higher value), then send the data to server

This can be done using a simple Python script.

import requests

url = 'https://mount-tunnel.web.actf.co/submit'
data = {'start': '16825199999'}

response = requests.post(url, data=data)

print(response.text)

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Flag: actf{wait_until_farewell_speedrun}