my-ctf-challenges

Challenges I created for CTFs

Table of contents

• Harekaze CTF 2018
• Harekaze CTF 2019
• zer0pts CTF 2020
• Harekaze mini CTF 2020
• zer0pts CTF 2021
• BSides Ahmedabad CTF 2021
• zer0pts CTF 2021
• zer0pts CTF 2023
• SatokiCTF 2024
• AlpacaHack Round 7 (Web)

Harekaze CTF 2018

609 teams registered, and 447 teams got at least 10 points.

CTFtime link: https://ctftime.org/event/549

Name	Category	Estimated Difficulty	Points	Solves	Solution (ja)
Obfuscated Password Checker	Web	easy	50	112	想定解法
Sokosoko Secure Uploader	Web	easy	100	57	想定解法
15 Puzzle	Rev	easy	200	44	想定解法
Logger	Rev+Net	medium	200	21	想定解法

Unpublished challenges

Sadly, there is an unpublished challenge.

Name	Estimated Difficulty	Category	Points	Solution
0-z	Web	medium	150	Solution (en, ja)

Harekaze CTF 2019

724 teams registered, and 523 teams got at least 10 points.

CTFtime link: https://ctftime.org/event/789

Name	Category	Estimated Difficulty	Points	Solves	Solver	Solution (ja)
scramble	Reversing	warmup	100	68	solver.py	想定解法
The Steganography Generator	Reversing	easy	200	10	solver.py	想定解法
Admin's Product key	Reversing	easy	200	8	solver1.py (static analysis), solver2.py (dynamic analysis)	想定解法
Encode & Encode	Web	warmup	100	54	-	想定解法
Easy Notes	Web	easy	200	10	solver.py	想定解法
SQLite Voting	Web	medium	350	3	solver.py	想定解法
Avatar Uploader 1	Misc	warmup	100	52	solver.png	想定解法
Avatar Uploader 2	Web	medium	300	11	solver.py	想定解法
[a-z().]	Misc	easy	200	36	-	想定解法

zer0pts CTF 2020

811 teams registered, and 432 teams got at least 1 points.

CTFtime link: https://ctftime.org/event/1006

Name	Category	Estimated Difficulty	Points	Solves	Solution
Can you guess it?	Web	warmup	338	44	English, Japanese
MusicBlog	Web	medium	653	13	English, Japanese
phpNantokaAdmin	Web	medium	755	8	English, Japanese

Harekaze mini CTF 2020

175 teams registered, and 141 teams got at least 1 points.

Name	Genre	Estimated Difficulty	Points	Solves	Solution
Easy Flag Checker	Reversing	warmup	130	55	Japanese
Tiny Flag Checker	Reversing	medium	193	23	Japanese
What time is it now?	Web	warmup	123	63	Japanese
JWT is secure	Web	easy	210	19	Japanese
Avatar Viewer	Web	medium	305	8	Japanese
WASM BF	Web	medium-hard	322	7	Japanese
Proxy Sandbox	Misc	medium-hard	322	7	Japanese

zer0pts CTF 2021

1447 teams registered, and 951 teams got at least 50 points.

CTFtime link: https://ctftime.org/event/1256

Name	Genre	Estimated Difficulty	Points	Solves	Solution
Kantan Calc	Web	easy-medium	135	50	English, Japanese
Simple Blog	Web	medium-hard	192	23	English, Japanese

BSides Ahmedabad CTF 2021

314 teams got at least 66 points.

CTFtime link: https://ctftime.org/event/1466

Name	Genre	Estimated Difficulty	Points	Solves	Solution
Roda	Web	easy	200	21	English, Japanese

Harekaze mini CTF 2021

109 teams registered, and 73 teams got at least 1 points.

Name	Genre	Points	Solves	Solution
Incomplete Blog	Web	201	21	Japanese
Osoraku Secure Note	Web	322	7	Japanese
Emoji Tsukuru	Web	500	1	Japanese
Let’s read wasm	Web	365	5	Japanese

zer0pts CTF 2023

476 teams got at least 53 points.

CTFtime link: https://ctftime.org/event/1972

Name	Genre	Estimated Difficulty	Points	Solves	Solution
Warmuprofile	Web	warmup	137	48	English, Japanese
jqi	Web	easy	149	40	English, Japanese
Neko Note	Web	easy-medium	181	26	English, Japanese
Plain Blog	Web	medium	239	14	English, Japanese

SatokiCTF 2024

101 teams got at least 1 point.

Name	Genre	Estimated Difficulty	Points	Solves	Solution
HBD	Misc	warmup	100	19	Japanese
zzz	Misc	warmup	100	21	Japanese
EXECjs	Web	satoki(hard)	500	1	Japanese

AlpacaHack Round 7 (Web)

78 users got at least 1 point.

Name	Genre	Estimated Difficulty	Points	Solves	Solution
Alpaca Poll	Web	easy	146	42	Japanese