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Daily AlpacaHack

A daily CTF challenge with a fun new puzzle every day

What is Daily AlpacaHack?

We publish one simple, beginner-friendly or educational CTF challenge every day!

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Solve within 24 hours of release to appear on the leaderboard.

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Today's Challenge
minaminaominaminao
Flag Printer 20XX
Misc
Medium
43 solves
Submissions (latest 3)
trimscash
trimscash

SOLVED!

Jun 19, 9:03 AM

ahnmo

SOLVED!

Jun 19, 8:46 AM

Leaderboard

Try the first challenge

Is this your first CTF? Let's begin by tackling the first challenge released on Daily AlpacaHack.

View challenge
admin
AlpacaHack 2100
Misc
Welcome🌱
1,896 solves
Upcoming challenges reveal the , , and in advance.
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Jun 2026

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1
admin
Half-Year Recap
Misc
Welcome🌱
222 solves
2
minaminaominaminao
Cache Me If You Can
Web
Easy🌱
186 solves
3
minaminaominaminao
vm1
Misc
Medium
92 solves
4
pppp4649pppp4649
Small e
Crypto
Easy🌱
127 solves
5
minaminaominaminao
RPS GAME
Misc
Crypto
Medium
95 solves
6
nozokare
Flag for localhost
Web
Easy🌱
146 solves
7
tan90909090tan90909090
C++ flag checker
Rev
Hard
81 solves
8
shiragishiragi
Guess IP
Misc
Easy🌱
132 solves
9
nozokare
A Piece of DHKE
Crypto
Medium
80 solves
10
shiragishiragi
chmod-swapper
Misc
Medium
80 solves
11
tchentchen
Alpaca Certification
Web
Easy🌱
146 solves
12
rsk0315
Floating Equality
Misc
Medium
89 solves
13
pppp4649pppp4649
Elliptic Equation
Crypto
Hard
57 solves
14
tchentchen
CAuth
Web
Hard
61 solves
15
minaminaominaminao
SITE/2
Web
Easy🌱
110 solves
16
tan90909090tan90909090
Xored PNG
Misc
Medium
83 solves
17
tchentchen
Looks like Alpacahack
Web
Medium
74 solves
18
shiragishiragi
Catrunner 2
Misc
Easy🌱
89 solves
19
minaminaominaminao
Flag Printer 20XX
Misc
Medium
43 solves
20
nozokare
Planned topicRNG
Crypto
Hard
21
Planned topicHeap
Pwn
Hard
22
Planned topicSecret Sharing
Crypto
Easy🌱
23
Planned topicNginx
Web
Medium
24
Coming soon
26
Coming soon
28
Planned topicTBA
Pwn
Hard
29
Coming soon
30
Coming soon
2
Coming soon
3
Coming soon
4
Coming soon
5
Coming soon

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Writeups

nirvana

Writeup for Catrunner 2

nirvana

ja
Catrunner 2

32 minutes ago

Daily AlpacaHackに挑戦するつくよみちゃん 06/18/Catrunner 2/shiragi

nirvana

Writeup for Looks like Alpacahack

Daily AlpacaHackに挑戦するつくよみちゃん 06/17/Looks like Alpacahack/tchen

tadanobutubutu

Writeup for Xored PNG

ja

2026/06/16 17:17

Daily AlpacaHackに挑戦するつくよみちゃん 06/16/Xored PNG/tan90909090

ja

2026/06/16 17:06

tadanobutubutu

Writeup for SITE/2

ja

2026/06/16 10:33

Rows:

Another Login Challenge

Topic: LoginReleased: Mar 13, 2026

143 solves
Web
Medium

by

tchen

tchen

Login, login, and login!

Beginner Hint 1 (AI-translated)
  • In index.js, a simple login feature is implemented.

  • It appears to check that users[username] exists and that users[username].password matches the provided password.

  • It doesn’t seem possible to create your own user. Also, a user called admin is registered, but guessing that password would be impossible.

Beginner Hint 2 (AI-translated)
  • In JavaScript, users["foobar"] and users.foobar are almost equivalent. Could this be used somehow?
  • The login form alone might not allow you to send the intended data. For methods of sending data without using a browser, refer to my writeup for I wanna be the Admin.
another-login-challenge.tar.gz

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