251112_hck4gCTF learning record
251112_hck4gCTF learning record
cvestoneIn the full-stack CTF player program, this article will be continuously updated with recreated learning content
Attachments
Release 251112_hck4gCTF · cvestone/cvestone.github.io · GitHub
EventInfo
ScoreBoard
My team 0xfun’s rank in this event - top 1:
crypto
confirm-wire-check
Desc
Somewhere in Ojoo/Orogun Ibadan Nigeria the market is just waking up.
A 17-year-old Hck4G whisperer just slipped a single velvet_postcard.zip into the dead-drop before her grandmother’s prayer bell rang.
No note just a trembling voice memo that plays once and dissolves:
“she sent me the postcard from Lagos
promised love, then asked for my school fees
i didn’t send money
i kept the card
inside: three layers
first the tune is wrong
slide it down one key
then the paper is folded wrong
unfold it flat
then the ribbon hides the truth
unwrap it gently
tell my grandma the fees are still mine”
She used her last ₦4,000 to keep her WAEC registration alive.
She doesn’t know that at 07:00 AM ACDT the same postcard will auto-forward to 8,000 Melbourne teens via a fake scholarship bot.
She doesn’t know the final whisper under the ribbon is the seed phrase that can drain 400 student savings accounts, or fund 400 real scholarships if the right hands open it first.
Hck4G is already holding the velvet at 06:13 AM because we don’t let grandmothers pray over empty fee receipts.
We hear the girl counting her coins in her sleep, dreaming of a desk with her name on it that only exists if we unfold the lie correctly.
One zip. One postcard. Three lies wrapped in silk.
Forty-seven minutes before the first teen clicks “claim now” and the ribbon becomes a noose.
Slide the tune. Unfold the paper. Unwrap the ribbon.
Read the heart she was meant to keep.
This is my serial Number:
544756305830466e646g396d5
958526f58325d76636f3954595
75d6f58306f7564475679626g5
6305831567d5957646f43673g3g
formular - C-EX-B
Key Points:
deepdecoder
Desc
Right now, a 14-year-old in Port Harcourt is staring at a wall of numbers on his cracked phone.
The boss just dropped the payload:
“Turn this into letters before sunrise or you’re out — and your family eats nothing tomorrow.”
He doesn’t know those digits spell the exact amount a widow in Perth will lose at 9 AM.
He doesn’t know the next message after decoding will be a death threat.
He only knows the numbers won’t stop blinking until he cracks them.
Hck4G was born for this silence —
the moment a child’s fingers hover over keys that could destroy two lives with one press.
The string is long.
The pattern is brutal.
The clock is cruel.
Decode what should never have been encoded.
Steal back one future before the numbers become a noose.
Key Points:
ancient-roman-secret
Desc
Somewhere tonight, a kid in a dimly lit room just sent a string of letters to a group chat.
The reply came instantly: “Perfect. No one outside the circle will ever read it.”
He thinks it’s just a game.
He thinks the words are harmless.
He doesn’t know they’re already written on someone else’s grave.
Hck4G lives in the space between that send button and the damage it will do.
We exist to intercept the message before it becomes a life sentence — for the sender and the soul on the other end.
The text is short.
The method is ancient.
The consequence is forever.
Read what should never have been written.
Pull one child back from the edge before the clock forgets them.
1 | j4<piY(62<0<6WQ02?504@6P4650<:5Q0Q92P60R960Q2>6072R6062Q:=W03P@<6?0E%6249%96>%@g?4PWNR{:T6QA |
Break me if you can - It will be counted as roman adult abuse.
Key Points:
pwn
myapp
Desc
In a quiet room in Calabar, the ceiling light just flickered once.
A 17-year-old closed his laptop 36 minutes ago, still smiling at the single line he typed in the crew chat before leaving for evening lesson:
just finished my classy application
basically unhackable
$150 if it survives the night
He used the advance to pay his JAMB coaching fees.
He doesn’t know that that same binary will sit on every point-of-sale terminal in Hobart’s waterfront restaurants.
He doesn’t know his “classy” fortress is the only thing keeping 300 waiters’ tips from disappearing before dessert.
Hck4G is already holding the wine list because we know even the classiest table has a loose leg if you know exactly where to kick.
We hear the creaks, begging us to find the the source before the waiter’s smile does.
One classy app.
Forty-one minutes before the first bill is printed and the tips start bleeding.
Find out how class this app really is.
Find the flag to stop the attack.
nc 15.206.70.2 8001
Key Points:
bird
Desc
Somewhere in Enugu the rain is drumming on a tin roof.
A 17-year-old left his laptop open exactly 29 minutes ago. The last thing he typed before running to buy his mum akara was a single line in the crew chat:
added a canary like the boss told me
if it sings = we’re dead
if it shuts up = $120 and new school shoes
He doesn’t know that at 13:00 PM ACDT the same binary will run on every ATM in Adelaide.
He doesn’t know the tiny bird he placed in the stack is the only thing keeping 40,000 pension cheques from vanishing before Christmas.
Hck4G is listening to the rain because we know exactly how to make a canary sing without waking the boss.
We hear the akara sizzling, begging us to hush the bird before it screams.
One binary.
One tiny bird guarding the vault.
Thirteen minutes before the first pensioner queues and the canary starts singing for the wrong audience.
nc 15.206.70.2 5000
Key Points:
printer-still-jammed
Desc
In a stuffy room in Kumasi, the ceiling fan is spinning lies.
A 22-year-old just hit upload 27 minutes ago and typed the proudest message of his life:
found your issue
fixed it
much secure use of printf now :)
just made an extra $50
He used the bonus to buy his sister a new dress.
He doesn’t know that at 14:30 PM ACDT the same binary will power every airport kiosk in Perth.
He doesn’t know his “much secure” printf is the only thing keeping 15,000 boarding passes from printing tomorrow’s flight plans for the black market.
Hck4G tilts the scales because we’ve seen “secure printf” before—right before it cried.
One “Secure” binary.
Twenty-seven minutes before the first passenger scans a ticket that shouldn’t exist.
Show it what “secure” really means.
Make the safe printf confess everything it swore to keep quiet.
nc 15.206.70.2 4747
Key Points:
jammed-printer
Desc
In a corner room in Kumasi, the ceiling bulb just buzzed like a trapped mosquito.
A 25-year-old pushed the final binary and typed one last message before heading to the market with the cash he just earned:
printy printy printf
He used the money to buy extra pepper and a new school shirt.
He doesn’t know that at 14:15 PM ACDT the same binary will run on every ticket printer in Melbourne’s tram network.
He doesn’t know his this will be the only thing keeping 120,000 daily commuters from paying with their entire life stories.
Hck4G is already typing the first format string at 13:51 PM because we love it when they brag about printf like it’s a toy.
We hear the pepper grinding in the mortar, begging us to make the printer speak the truth before it starts printing tomorrow’s nightmares.
One chatty binary.
It tells secrets, flags—if you ask it nicely.
Ask it nicely and it might just give you the flag.
nc 15.206.70.2 4646
Key Points:
getting-full
Desc
A 16-year-old left his laptop on 44 minutes ago.
The screen still glows with the last command he typed before running to buy water:
./nc_listener 15.206.70.2:1337.
the exact no. of bytes feeds me
anymore makes me choke
Press enter to execute…
He doesn’t know that at 12:30 PM ACDT the same listener will open on every smart-fridge in Perth’s biggest hospital.
He doesn’t know the extra byte that makes him “choke” is the only thing keeping 200 patients breathing.
Hck4G is already on it because we know exactly how many characters it takes to turn a choke into a confession.
We hear the water flowing, begging us to listen before the boss does.
One listener.
One press of the enter key.
Nine minutes before the insulin pumps freeze and the sachets turn to handcuffs.
Hack in and find the flag.
Quickly before he gets back to execute it!
nc 15.206.70.2 1337
Key Points:
interpreter
Desc
In a small room in Benin City the ceiling fan just died again.
A 16-year-old is staring at his first-ever C program, still proud from last night.
He posted the binary to the crew with a single note:
“Learnt how to code in C recently
so i decided to make a mini interpreter
i don’t know how secured it is
help me check”
He used the $90 advance to buy himself a new pair of shoes.
He doesn’t know that at 13:30 PM ACDT the same binary will run on every library computer in Canberra.
He doesn’t know his “genius” interpreter is the only thing standing between 8,000 students and a lifetime of leaked exam papers.
Hck4G is already typing the first sentence now because we know every kid who says “nothing can break it” is secretly begging the world to prove him wrong before the pot boils over with blood.
One baby interpreter.
vulnerability.
Twenty-five minutes before the first student logs in and the tongue starts confessing secrets it was never meant to know.
Speak to it in a language it wasn’t taught yet.
Make it spit out the flag instead of tomorrow’s future.
nc 15.206.70.2 8000
Key Points:
register
Desc
Register
300
Right now, in a dark corner of Ghana, a 17-year-old just uploaded the final binary to the crew’s server.
The boss sent one message:
“Rules are simple:
- No root
- No shell
- No flag for anyone except me
Break one, you’re out. Break all, you’re dead.”
The kid followed every rule.
He chained the buffers, he locked the doors, he even added a smiley in the source comment
He doesn’t know those same rules were written to be broken by someone who still believes in second chances.
He doesn’t know that at Hck4G CTF, the entire game is about to flip.
Hck4G doesn’t play by syndicate rules. We rewrite them.
We turn “no shell” into “new beginning”.
We turn “no flag” into “no more chains”.
One binary.
One set of “un”breakable rules.
Break every rule they gave him.
Change the game before the game changes him forever.
nc 15.206.70.2 9905
Key Points:
mgmt
Desc
A 17-year-old fell asleep on the mat 57 minutes ago, laptop still open.
The terminal glows with the last thing he wrote:
./cat file.txt
i show whatever logic you choose
but if you speak too loud
i forget who i am
and scream the real count
He’s clutching the $95 for his sister’s school fees like a lifeline.
He doesn’t know that at 12:45 PM every voting machine in Tasmania will run the same binary.
He doesn’t know “whatever logic you choose” means something entirely unrelated to the election.
Hck4G is typing the loudest whisper at 12:33 PM because we know exactly how many decibels it takes to make a liar tell the truth.
We know the paycheck form is still blank, waiting for a future that isn’t written in disappearing ink.
One binary.
Logical thinking.
Twelve minutes before the polls close and the echo becomes a scream that can’t be unsaid.
nc 15.206.70.2 8003
Key Points:
steganography
the_advocator
Desc
The_Advocator
100
Somewhere in Ibadan the dawn is still a rumor.
A 16-year-old Hck4G guardian just slid a USB with a single .rar file under the door of the safe house before his sister’s alarm rang.
There was a single note scribbled on it
“not just a pic…”
He doesn’t know that at the secret inside will auto-unlock on every Nigerian embassy server worldwide.
He doesn’t know the diary in the margins holds the master passphrase that can freeze 42 syndicate wallets, or drain 3,000 pensioners if the wrong knock is used.
Hck4G has already uploaded the file for you to analyse, because we know a single picture can speak 1,000 words.
…especially if we read between the pixels.
One zip.
One photo.
Fifty-four minutes before the first embassy clerk logs in and the margins start bleeding.
Find the words the picture is trying to speak.
Find the secret inside
Download file here
Key Points:
paste_aza
Desc
It appear that someone has gained access to Hck4G that is not hacking for good!
We caught them and managed to snag one of the files they left behind, which should look fairly familiar
You know our mission by now
You know who we are helping
You know what we are trying to stop
Hck4G has already uploaded the file.
We hear the the regret in the voices of these cyber criminals from behind their screens and we won’t stop until we’ve made a difference.
Download the file.
Find the flag.
Not long until the event ends!
Stare until the pixels speak.
Download file here
Made with 💘 by Th3_Se3k3r🥷.
Key Points:
forensics
pickers_back_door
Desc
Pickers_Back_Door
200
Somewhere in a Kumasi cyber-café the lights just flickered twice.
A 14-year-old just stole a single .pcap file and slipped it onto the dead-drop server before the owner woke up followed by one short message:
“i watched the crew’s laptop for a few nights
the devices talk to each other
the chatter is subtle, but makes a lot of noise
there’s something suspiscious happening
…
…
tell my mum the rent is paid”
He used his last $100 to pay towards rent in advance.
He doesn’t know that at 06:30 AM ACDT info inside that pcap holds the key to stop an auto-load on every Victoria Police precinct server.
Hck4G is has already got the file inside a .zip for you to analyse, because we don’t let rent money vanish over bad ARP.
We hear the mum counting the naira in her sleep, dreaming of a roof that only stays if we read the local chatter right.
A single pcap.
A secret hidden deep in the packets
Sixty-one minutes before the owners alarm goes off.
Listen to the chatter
Look for anything suspiscious
Find the traffic origin
Download file here
Key Points:
f1nding-cl1ents
Desc
F1nding-CL1ents
200
Somewhere in Tamale the market is still asleep.
A 19-year-old recruit just dropped a single .zip into the dead-drop
He left no note—just a cracked voice memo that plays once and deletes itself:
“Listen carefully:
not every client is a customer
not every request deserves a reply”
He just used his last $100 to buy her a new secondary-school uniform.
He realise the hidden flag in the .zip will auto-unpack on every Melbourne council server.
He doesn’t know the honest packets hold the master key that can lock out three syndicates—or open 1.2 million voter records if the wrong ears listen first.
Hck4G is already inside the .zip file because we don’t let uniforms go unworn over bad decryption.
We hear the sister ironing the creases in her sleep, dreaming of a first day that only exists if we separate signal from static.
Follow the honest voices in the noise
Trace their path
Uncover the truth
Listen for the voices that don’t lie.
String the honest packets together—they spell the key in plaintext.
Download file here
Key Points:
mobile-bapi
Desc
Three minutes ago, a 16-year-old in Lagos flashed the final build onto a cheap Android burner.
The commandant slid the .apk across Telegram with one line:
“Hardcode the key. No one ever looks inside a school-grades app.”
He did it in a matter of seconds.
He never knew that single string of characters is the master key to every victim’s private life tomorrow morning.
He only knew his mum’s rent is due at 7 AM and the crew pays on delivery.
If they find out he left the back door wide open, his phone gets smashed and his mum’s rent doesn’t get paid again.
If they don’t, a thousand Melbourne teenagers wake up to leaked nudes and suicide threats.
Hck4G was forged to stop this from ever being a decision in the first place.
There’s a hidden key buried in the .apk file.
The first victim’s phone just lit up with a push notification.
Quick! Find the flag before the first scream hits the group chat.
Key Points:
drums
Desc
A 15-year-old in Kumasi just hit send on a 10-second voice note.
To his mum it’s a birthday beat of 39 drum hits on a plastic bucket.
To the syndicate it’s tonight’s drop, Hiding within each byte.
He thinks the rhythm is just noise.
He doesn’t know it’s the sound of a Perth pensioner losing everything before breakfast.
Hck4G was made to tune this heartbeat —
when a child’s drum solo becomes someone else’s funeral march.
The file is tiny.
The beat is loud.
The countdown is real.
Sometimes things are not as they appear.
Find the syndicate’s hidden message.
Key Points:
frys-copypasta-nightmare
Desc
Fry was rushing through a “prove-you’re-human” check on a shady login page.
One click.
Clipboard silently swapped.
Next thing he knows—$847 charged to his card for 500 BBQ gift vouchers he never ordered.
Somewhere in Nigeria, a 15-year-old just earned $20 for pasting a single line of text.
Hck4G refuses to let another kid grow up thinking copy-pasta scams are “easy money.”
Your job: reconstruct exactly what was in Fry’s clipboard the moment everything went wrong.
Find the malicious string.
Submit it as the flag.
Prove how one overlooked paste can ruin two lives at once.
Hunt to Capture the flag.
Key Points:
dumpster
Desc
Seven minutes ago, an 18-year-old in Tema shut the lid on a battered Linux laptop and slipped out the door.
The boss had barked: “Leave the old drive in the drawer. Take the new one. Move.”
He obeyed, but he forgot one thing.
Scattered across the filesystem sits a trail of files he was ordered to burn.
One of them holds the key the crew needs to bleed a Melbourne hospital dry.
If they discover what he left behind, his little brother’s surgery money vanishes.
If they don’t, someone else’s life does.
Hck4G stands in this gap—
the razor-thin space where a teenager’s mistake can still be turned into a second chance instead of a life sentence.
The drive is still warm.
The files are still there.
The crew will be back any minute.
See what you can find before they do.
Key Points:
osint
tenet
Desc
Time is relative. We are not bound to any specific moment or location. Either way, Hck4G will not be wasting any of it letting young people be coerced into a life of crime by cyber criminals!
However… Just in case we ever did need to go back in time, I made a time machine. I left my first prototype near the location in this picture I took.
Can you find it for me?
I think I parked it sometime in 2014?
I’m sure it was around here
The flag is: Hck4G{NUMBER PLATE OF A VEHICLE}
Key Points:
ghost-of-the-street
Desc
Ghost-of-the-street
200
Somewhere in a Lagos safe house, a 25 year-old ghost just pulled the greatest recovery of his life.
Seventeen hours ago he breached the crew’s cloud backup and exfiltrated a single Ghost+of+the+street.zip before the connection died. He knows this must be the location for the drop and if he finds it and send it to the crew, he doesn’t have to use his last $50 for food tonight.
He doesn’t know that at 06:00 AM the cartel will be waiting at the drop-zone to see who shows up.
He doesn’t know the drop is a micro-SD with the ledger that can jail 27 traffickers and free 180 kids before the shoes even scuff.
Hck4G is already dragging the slider on Google Street because we don’t let honeypots destroy dreams.
We hear the ghost clicking away in his sleep, dreaming of a paycheck that doesn’t exists.
One zip file.
One photo.
Only minutes before the ghost sends the crew the wrong location and he truly becomes a ghost forever.
Find the location of the drop.
Submit the business name that lived there in 2010.
Flag Format: Hck4G{--_------}
Download file here
Key Points:
dont-be-too-forgetful
Desc
John Do did NOT finish his cyber-awareness training.
He just uploaded a photo of the office on Bluesky.
The Gen-Z is the worst, I can’t tolerate his 6 7 brainrot thingy. who knows what else got leaked!!
Key Points:
theseeker
Desc
Sebastian Coulombe, a senior privileged user is suspected of having his account compromised.
Seb holds elevated administrative rights across critical systems. New logins pop up everywhere, his account credential is probably lying in public. Can you find his hotmail credential?
The flag is Hck4G{Seb account password ending with 26f5}
Key Points:
bridge
Desc
Somewhere in Lagos, a 19-year-old ex-Yahoo boy turned Hck4G informant just went dark.
His last act before vanishing was to send Officer Johnson a single photo—no caption, no voice note, just a bridge at golden hour.
Forty-one hours ago he had whispered on an encrypted call:
“if anything happens to me
the evidence is in the church locker
safe house is under the bridge on the hill
only this photo knows which one”
He doesn’t know the safe house under that bridge is the only place left hiding the ledger that can dismantle three syndicates and free 400 kids.
Hck4G is staring at the bridge.png and we don’t let brothers disappear with school bags still empty.
Find the name of the bridge and city
Forty-six minutes before the crew’s vans roll out and the wrong bridge burns.
Flag Format: Hck4G:{————-————}
Download file here
Key Points:
web
cloudy_scam
Desc
Some where in the cloud, a throwaway app is running.
It was built fast, deployed faster, and handed to a kid who was told “just click run.” They never explained what it really does. They never showed the damage it leaves behind.
Hck4G refuses to let another teenager become tomorrow’s perpetrator because poverty left them no choice.
Your job: Find the app. Break in. Take the flag that’s hiding.
Every exploit you land is proof the cycle can be broken.
Capture the flag. Be the protector they never had.
Could this be the App?
https://cloudyscam.hck4g.org/
Key Points:
first
Desc
Right now, a 16-year-old in Abuja just finished writing the shopping app you’re looking at.
The syndicate paid him in mobile data and a promise:
“Add one hidden field. No one will ever notice. Just a note for the boss.”
He doesn’t know that note contains tomorrow’s ransom demand.
He doesn’t know the next victim is someone’s grandmother in Melbourne.
He only knows his little sister needs school fees next week.
Hck4G was created for this exact moment.
when one line of code decides whether a kid becomes a criminal or a protector.
The basket is open.
The list looks innocent.
The secret is already inside.
Find it before midnight becomes the timestamp on another life sentence.
https://siab.hck4g.org/login
