HEX ADVENT 2025: Crack the Advent, Conquer the Threat 🐛
Last chance to register! Registration closing on 20 Dec 2025, 09:00 SGT!
WELCOME TO HEX ADVENT 2025, ‘tis the season to Unwrap Your Potential! 🎁
HEX ADVENT 2025 is a Christmas-themed CTF Advent Calendar, designed for women, by women.
What to Expect
- 12 Days, 12 Challenges: A structured schedule to build mastery across different CTF categories.
- Focus Areas:
- Pwn (Binary Exploitation)
- Cryptography
- Reverse Engineering
- Forensics
- OSINT
- Web Exploitation
- Our Mission: To empower women in cybersecurity, create visible role models, and cultivate a robust local talent pool.
| Date | What To Expect? |
|---|---|
| 1 to 12 Dec 2025 | New challenges unlocked at 09:00 SGT daily |
| 1 to 31 Dec 2025 | Challenges open until 31 Dec 2025, 23:59 SGT |
| 1 Dec 2025 to 5 Jan 2026 | Write-up submissions will close on 5 Jan 2026, 23:59 SGT |
✍🏻➡️ REGISTER TO PLAY NOW
✅➡️ Fill in this Google Form to confirm your eligibility
📝➡️ Submit your write-ups
Event Information & Rules
Please refer to this blog post for the full Event Information and Rules.
Prize Haul
A challenge is considered solved when the correct flag is submitted on CTFd before the final deadline: 31 December 2025, 23:59 SGT.
💰 Cumulative & Shared Prize Pools
| Challenges Solved | Prize Pool |
|---|---|
| 10 | |
| 11 | |
| 12 |
💰 We are doubling the prize pools!
The cash prizes are cumulative, and shared equally among all eligible players at each tier.
Example: Players solving 12 challenges stand to receive a share of the S$800, S$1400, and S$2000 pools.
Note: If you solve 10/11/12 challenges in total, the write-ups for three specific challenges are mandatory to verify your eligibility for the prize pools.
🎄 In the spirit of this season of giving:
- If any winner chooses not to claim their cash prize, STAR Labs SG Pte. Ltd. will match it dollar-for-dollar and donate to either “Breast Cancer Foundation” or “Make-A-Wish Foundation”. Just let us know.
- Even if everyone takes their winnings (which is perfectly fine!), STAR Labs SG Pte. Ltd. will still be making donations to both organisations.
🎁 Exclusive Swags
| Challenges Solved | Swag |
|---|---|
| ≥ 1 | Exclusive Event T-shirt |
| ≥ 6 | T-shirt, Pin, Key Chain |
| ≥ 10 | All Swags + A share of the three cash prize pools |
Swags are awarded to individuals, and are not shared.
To receive the T-shirt in your preferred size, register on CTFd, and confirm your eligibility by 15 December 2025.
IMPORTANT: All players must submit their details through the Google Form to confirm their eligibility and claim the prizes.
✍🏻 Best Write-Up Prize
We are awarding 3 prizes of S$100 each for the Best Write-Up submissions. Level up your explanation and documentation skills by submitting a write-up for the intermediate pwn, crypto, and reverse engineering challenges!
📋 Write-Up Submission Rules
Write-ups are generally optional, but they are required for prize eligibility in two cases:
- Best Write-Up Prize (Optional): You may optionally submit a write-up for this challenge to compete for the S$100 Best Write-Up Prize.
- For Top Solvers (Mandatory): If you solve 10/11/12 challenges in total, the write-ups for three specific challenges are mandatory to verify your eligibility for the prize pools.
‼️Deadline Extension for Write-Ups!
Write-ups must be submitted by 5 January 2026, 23:59 SGT at this Google Form. You are not allowed to publicly post write-ups or discuss the solutions until HEX ADVENT 2025 officially ends on 31 December 2025, 23:59 SGT.
Winning entries will be featured and published on our social media platforms.
📦 Prize Collection
Winners will be notified in January-2026 with the collection details.
❓ Frequently Asked Questions
View our FAQs here
or join the Discord channel for Hex Advent: https://discord.gg/qBEdNFamGs
Credits:
- Challenge Authors: Ada Lum, Ariana Goh, Cherie-Anne Lee, Verity Lim, Wu Yuewei, Yvonne Chua
- Poster Designer: Sarah Tan
- Organising Team: Alicia Ho, Carol Ng, Frances Loy, Joel Wong, Lauren Chua, Sarah Tan
Challenges
Day 1: LAUNCH - HEX ADVENT 2025 is LIVE! Hack Our Christmas Wishlist🎄!
🚨 The Hex Advent Challenge is officially LIVE! Our first challenge, “Christmas Wishlist🎄” by Wu Yuewei, is from the Web Exploitation category. Login or register on our CTFd platform and start playing immediately!
👾 Start hacking: CTFd Platform
✅ Confirm your prize eligibility
Day 2: Merry Osintmas, The Flag is Out There!
Flag 1 captured? Sweet! “Merry Osintmas", written by Ada Lum, is now available. Login or register now and gain access to all the challenges released so far. HEX ADVENT 2025 remains open until 31 December 2025, 23:59 SGT.
👾 Solve Merry Osintmas: CTFd Platform
✅ Confirm your prize eligibility
Day 3: Pwn and Climb the Ranks with Make A Wish!
Challenge the rankings with “Make A Wish”, written by Cherie-Anne Lee. Climb the leaderboard, login or register to play immediately and see how you stack up!
💫 Check scores & “Make A Wish”: CTFd Platform
✅ Confirm your prize eligibility
Day 4: Hex xor bin is Ready for Decryption!
Written by Ariana Goh, today’s challenge, “Hex xor bin” will test your Crypto expertise. Login or register today and access the full set of challenges. Start decrypting!
👾 Tackle Hex xor bin: CTFd Platform
✅ Confirm your prize eligibility
Day 5: Mid-Week Status – Disassemble the Christmas Tree! 🎄
It’s never too late to patch the gap while tackling “Christmas Tree” by Verity Lim. Login or register now and gain access to catch up on all previous challenges 👇🏻
👾 Catch up & play: CTFd Platform
✅ Confirm your prize eligibility
Day 6: Caught You! Querying Flags is Now Spinning! 🕸️
Spider-senses are tingling! Unravel the source code and test your Web Exploitation skills with “Querying Flags” by Ariana Goh. The flag is waiting to be caught, login or register now and start the hunt!
👾 Play now: CTFd Platform
✅ Confirm your prize eligibility
Day 7: Halfway There! Decode “Santa’s Message”!
We’re officially halfway through the challenges in HEX ADVENT 2025! Verity Lim invites you to test your investigative skills with the Forensics puzzle: “Santa’s Message”.
Join the event anytime! We welcome players to register, access all the released challenges so far, and work through them at your own pace.
👾 Detective work starts now: CTFd Platform
✅ Confirm your prize eligibility
Day 8: Level Up with HEX ADVENT 2025’s First Intermediate Challenge – Ho Ho Heap!
Time to see how you stack up, our first Intermediate challenge is here! Test your skills with the Pwn challenge: “Ho Ho Heap!”, written by Cherie-Anne Lee.
Log in or register now to access all challenges released so far and tackle this new difficulty tier!
👾 Go to “Ho Ho Heap!”: CTFd Platform
✅ Confirm your prize eligibility
📝 Submit your write-up to compete for the Best Write-Up Prize!
(Note: Mandatory write-ups are required for players who solved 10/11/12 challenges. Eligibility will be verified before prizes are disbursed.)
Day 9: Time For A Sequel with Merry Osintmas 2!
Ada Lum brings you the highly-anticipated sequel! “Merry Osintmas 2” is a fun throwback to Day 2’s “Merry Osintmas”, while also testing your OSINT skills.
Only 3 daily unveils left! While the reveals end soon, you have until 31 December 2025, 23:59 SGT to complete all challenges. Start playing now to catch the final releases!
👾 Play the sequel: CTFd Platform
✅ Confirm your prize eligibility
Day 10: Promptly Pivot Your Way Through the v0 Net!
This web challenge will really get you tangled up! The pressure is on to secure your spot on the scoreboard.
Showcase your pivoting and exploitation skills in Yvonne Chua’s “Prompt-to-Pivot: Echoes of v0”. Don’t worry if your initial attempt is giving you a dead end, just give it little prompt-ing and pivot to another angle 😉
Log in or register now to access all the challenges today!
👾 Inspect the element: CTFd Platform
✅ Confirm your prize eligibility
Day 11: Final Countdown Nears! Small and Simple Things Are Here!
“Small and Simple Things”, authored by Ariana Goh, is a tricky one that demands your Crypto skills. Yes, the challenge name says “Simple”, but finding the right key is rarely elementary.
Login or register today – all challenges (Days 1 to 11) are open for competing until 31 December 2025, 23:59 SGT!
P/S: Our surprise reveal happens tomorrow 😉 Be here at 09:00 SGT or be square!
👾 Dive into “Small and Simple Things”: CTFd Platform
✅ Confirm your prize eligibility
📝 Submit your write-up to compete for the Best Write-Up Prize!
(Note: Mandatory write-ups are required for players who solved 10/11/12 challenges. Eligibility will be verified before prizes are disbursed.)
Day 12: Final Challenge: Debug Your Way Through The Christmas Lottery!
The curtain calls on HEX ADVENT 2025’S challenges with “Christmas Lottery” by Verity Lim. Debug your way through this challenge and reverse engineer your way to the prize!
T-SHIRT REVEAL BONUS! The last piece of HEX’S ADVENT 2025’s calendar is unlocked, and thus a reveal of the artwork on our exclusive event T-shirt today. Solve at least one challenge to receive the shirt!
Log in or register now to finish strong. Remember, all 12 challenges remain open on our CTFd platform until 31 December 2025, 23:59 SGT. Good luck!
👾 The last flag awaits: CTFd Platform
✅ Confirm your prize eligibility
📝 Submit your write-up to compete for the Best Write-Up Prize!
(Note: Mandatory write-ups are required for players who solved 10/11/12 challenges. Eligibility will be verified before prizes are disbursed.)