Binary_Search

Binary_Search

Want to play a game? As you use more of the shell, you might be interested in how they work! Binary search is a classic algorithm used to quickly find an item in a sorted list. Can you find the flag? You'll have 1000 possibilities and only 10 guesses. Cyber security often has a huge amount of data to look through - from logs, vulnerability reports, and forensics. Practicing the fundamentals manually might help you in the future when you have to write your own tools! You can download the challenge files here:

• challenge.zip ssh -p 63767 [email protected] Using the password 83dcefb7. Accept the fingerprint with yes, and ls once connected to begin. Remember, in a shell, passwords are hidden!

Solution

1. So, we're supposed to guess a number. Since we're told whether our guess was higher or lower that the right number we can apply the binary-search algorithm to find the number.
2. sshpass -p 83dcefb7 ssh -p 63767 [email protected]
3. This winning round I guessed 500, 250, 125, 200, 225, 210, 215, 213, and 213 was right.

Flag

Flag: picoCTF{g00d_gu355_ee8225d0}