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Daily AlpacaHack

A CTF challenge series with fun puzzles to enjoy every day

What is Daily AlpacaHack?

We regularly publish simple, beginner-friendly or educational CTF challenges!

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Solve each challenge within its time window to appear on the leaderboard.

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Today's Challenge
2501
Lean as a Service
Misc
Medium
36 solves
Submissions (latest 3)
onotch

SOLVED!

Oct 31, 12:24 PM

ctf-udon

SOLVED!

Oct 30, 3:40 PM

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🌱
2,327 solves
Upcoming challenges reveal the , , and in advance.
Prev

Oct 2026

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k0080k0080
what is my pointer 2
Pwn
Hard
50 solves
1
admin
Baby Alpaca
Misc
Welcome🌱
173 solves
2
tan90909090tan90909090
C# File-based app
Rev
Easy🌱
87 solves
3-4
2501
Shared Prime
Crypto
Medium
92 solves
5-8
tan90909090tan90909090
fsbase modification
Pwn
Hard
64 solves
9-12
2501
Almost Shared Prime
Crypto
Hard
46 solves
 
2501
Almost Shared Prime
Crypto
Hard
46 solves
13-14
tan90909090tan90909090
cowsay jail
Misc
Medium
63 solves
15-18
hiikunzhiikunz
decreasing
Misc
Hard
35 solves
19-22
tan90909090tan90909090
x32 ABI flag checker
Rev
Hard
34 solves
23-24
pppp4649pppp4649
Σecret
Crypto
Easy🌱
52 solves
25-28
k0080k0080
what is my pointer 4
Pwn
Hard
39 solves
 
k0080k0080
what is my pointer 4
Pwn
Hard
39 solves
29-31
2501
Lean as a Service
Misc
Medium
36 solves
1
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Writeups

claritys

Writeup for alloc-101

claritys

en
alloc-101

1 hour ago

claritys

Writeup for login-bonus (English)

en

2 hours ago

claritys

Writeup for Integer Writer (with brief explanation)

tadanobutubutu

Writeup for what is my pointer 4

tadanobutubutu

Writeup for Σecret

ja

2026/10/24 16:37

Rows:

login-bonus

Topic: C StringsReleased: Dec 17, 2025

314 solves
Pwn
Medium4.5

by

ptr-yudai

ptr-yudai

USER

SOLVED AT

claritys

claritys

4 hours ago

2026/10/30 12:02

2026/10/27 11:30

2026/10/25 17:49

2026/10/12 13:36

2026/10/10 17:33

2026/10/10 15:47

2026/10/07 11:39

2026/10/01 05:00

2026/09/28 06:36

2026/09/27 09:51

2026/09/24 13:43

2026/09/18 09:01

2026/09/14 01:34

2026/09/05 12:19

2026/08/22 01:18

2026/08/18 17:10

2026/08/13 10:50

2026/08/11 11:40

2026/08/08 23:40

2026/08/08 08:27

2026/08/07 11:29

2026/08/01 05:40

2026/07/30 14:53

2026/07/27 11:56

Rows:

descriptionsolveswriteups