AlpacaHack Logo
Sign InSign Up
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!

Join Anytime

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

Not a Competition

Discussion with friends or AI is welcome (account sharing is prohibited).

Solution Sharing Rules

Sharing solutions is allowed only after the challenge period has ended.

Solve stats

0

/5

No solved challenges yet.

Sign In to view your player stats

Today's Challenge
minaminaominaminao
Bitflip RSA
Crypto
Hard
34 solves
Submissions (latest 3)
nuhe

SOLVED!

Sep 7, 3:18 PM

dokkanot

SOLVED!

Sep 7, 8:14 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🌱
2,187 solves
Upcoming challenges reveal the , , and in advance.
Prev

Sep 2026

Next
Solved
Unsolved
Upcoming
Mon
Tue
Wed
Thu
Fri
Sat
Sun
 
tchentchen
Springing
Web
Medium
67 solves
1
admin
QUIZ ALPACASHOCK
Misc
Welcome🌱
95 solves
2
hiikunzhiikunz
base 16-32-64
Misc
Easy🌱
76 solves
3-4
tan90909090tan90909090
Let's Shut Down Linux
Misc
Medium
52 solves
5
baumroll1234
6-8
minaminaominaminao
Bitflip RSA
Crypto
Hard
34 solves
 
minaminaominaminao
Bitflip RSA
Crypto
Hard
34 solves
9
Coming soon
10
Coming soon
11
Coming soon
12
Coming soon
13
Coming soon
14
Coming soon
15
Coming soon
16
Coming soon
17
Coming soon
18
Coming soon
19
Coming soon
20
Coming soon
21
Coming soon
22
Coming soon
23
Coming soon
24
Coming soon
25
Coming soon
26
Coming soon
27
Coming soon
28
Coming soon
29
Coming soon
30
Coming soon
1
Coming soon
2
Coming soon
3
Coming soon
4
Coming soon

Want a harder challenge?

Go to B-SIDE

Writeups

gattoartz

Writeup for Leaked Flag Checker

gattoartz

ja
Leaked Flag Checker

5 hours ago

gattoartz

Writeup for a fact of CTF

gattoartz

Writeup for AlpacaHack 2100

Writeup for Vending Machine: Revised Version

author
ja

2026/09/06 15:02

nitcelcius

Writeup for Vending Machine: Revised Version (warn: some code reading ahead)

nitcelcius

Writeup for Let's Shut Down Linux (with reading)

curetwinkle

Writeup for Springing

ja

2026/09/05 05:10

Rows:

func-array

Topic: Function PointerReleased: May 6, 2026

184 solves
Pwn
Easy🌱2.5

by

trimscash

trimscash

Array of Alpaca function pointers 🦙🦙🦙🦙🦙

Beginner Hint (AI-translated)
  • This problem belongs to the Pwn category, specifically Pwnable (Binary Exploitation).
  • The goal is to launch a shell by executing the win function in a remote environment.
  • The asm volatile("mov $0,%spl"); in the win function is a process to simplify the problem. When calling the system function, rsp must be a multiple of 16. So, to simplify the problem here, we make rsp a multiple of 16 by setting the lower byte of rsp to 0. With this, we can execute the win function without worrying about it in this case. Reference
  • alpaca_functions is an array of function pointers placed on the stack.
  • When a function is called, the return address, the address to return to the original function, is placed on the stack.
func-array.tar.gz

Please sign in to submit the flag.

descriptionsolveswriteups