Asking b14g for 0 CORE, 99 times in one transaction, took 97M CORE. 70% of it has not moved

01 · What happenedThe b14g hack: requests for 0 CORE took 97M

On Saturday morning, 91 staking positions on b14g were emptied at once. One transaction took 97 million CORE. At that morning's price it was worth $1.47 million. Every request in it had asked for nothing.

b14g is a Bitcoin staking app on Core, a blockchain that pays Bitcoin holders to lock up their BTC. Core has its own coin, CORE, and it pays more when a holder stakes CORE next to their bitcoin. b14g matches the two sides. Bitcoin holders open what b14g calls merge orders, CORE holders fill them with their coins, and both share the higher reward.

At 09:29 UTC, a wallet that had existed for half an hour, which we call wallet A, sent b14g a list of withdrawal requests. Each named a b14g order that the wallet had never put a coin into, and each asked for 0. Every order paid out in full, 97 million coins in all, to the wallet that asked.

b14g confirmed the theft on X seven hours later and named two attacker wallets. Core is not yet in Bitquery's own data, so we read the chain's public records directly, from the request itself to every transfer after it. The bug sat in the same withdrawal that b14g users had made every day since at least 28 October. It took b14g more than an hour to stop withdrawals, and the service that paid the attacker's fees took 11.0M of the loot later that morning.

02 · How b14g worksHow a b14g withdrawal works

Each b14g order is a small program on the chain, a contract, that holds CORE and keeps it staked with a validator, one of the computers that run the chain and earn its rewards. The bitcoin side never leaves Bitcoin. It sits in a time lock on the Bitcoin chain, locked until a set date.

To take coins out, a holder sends b14g three things: the order, its validator, and how much they want back. b14g passes the request to the staking contract, the part of Core's own code that holds every staked coin, and the coins come back.

From 28 October until the drain, 6 wallets made 8 such withdrawals through the same contract. Each asked for a set amount and got exactly that.

03 · Asking for zeroHow the b14g exploit worked: asking for 0 CORE

The attacker's request had the same shape, with one change. Every entry asked for 0 CORE.

Core's own staking code treats a request for 0 as a request for everything the staker has with that validator. Each b14g order is the staker in the chain's eyes. So when b14g passed a 0 along, the whole order came out.

b14g let the zeros through. Its contract logged each request as 0, and it took them from a wallet that had funded no order at all. The staking contract logged the full 97 million as released, and all of it went to the wallet that asked.

We have not seen b14g's code, so we cannot point to the faulty line. The record shows what got through: a request for nothing, from a wallet with no stake, paid in full. A single bad number did similar damage earlier this month in the WAX bridge hack, where a minus sign drained a bridge.

The orders were not small. Those holding more than 1 million coins each made up 90% of what was taken.

04 · No stolen keyNo stolen key and no new code

Some thefts start with a stolen key, as in the Predict.fun hack. Others start with new code pushed in a hurry. We checked both, and neither fits.

b14g's contract is a proxy, a fixed address whose logic its owners can swap. The logic it ran during the drain had been its standing version for 17 months. b14g's multisig, a wallet that needs several of its owners to sign, does upkeep by swapping in a helper and swapping the same logic back in one step. It had done that 36 times since late December, most recently the day before the hack, and each time it put the same logic back.

The attacker's wallet was new. Its only money was a small amount of CORE for fees, sent half an hour before the drain, and no b14g record named it before. Its first call to b14g was the drain itself.

05 · 66 minutes66 minutes from the b14g drain to the pause

The contract has a pause switch, which stops every withdrawal. It took 66 minutes to come on.

Eight minutes after the drain, b14g's multisig ran its usual upkeep step on seven contracts, and withdrawals stayed open. Later, a user took out 80 CORE through the same function, the normal way.

By then the attacker was moving. Within the hour, 23.4M CORE had left wallet A through a string of new addresses. Then, 42 seconds after the pause, wallet A moved the rest to a second wallet, wallet B.

b14g said it paused the contracts as soon as it found the problem. We cannot see when that was. The record shows the pause 66 minutes after the drain.

06 · Where it wentWhere the stolen CORE went: Bybit, MEXC and Gate.io

Each of the 15 new addresses received one transfer and sent it on in a single transaction. Twelve passed their coins to busy wallets, the way an exchange sweeps the deposit addresses it gives each customer into a main wallet. Two passed theirs to fresh wallets that have not moved since, and one sent almost everything back to wallet B.

Two of those twelve fed a Bybit hot wallet, the exchange's working wallet for payouts. Our address labels place the same address on Bybit's proof-of-reserves list, the wallets Bybit names on other chains to show it holds its customers' coins. The other ten fed two busy, unlabeled wallets we call service X and service Y. Both take coins through one-time deposit addresses and pass them on to large exchanges, the pattern of an exchange or a swap service.

Within 90 minutes, service X had moved some of what it took on to addresses that our labels tag as Bybit and Gate.io deposits. Service Y passed what it took to a MEXC deposit address the same morning. These services hold other customers' coins as well, so their later transfers show where CORE went that morning. They do not prove which coins were stolen.

The address that sent its coins back took 5M CORE from wallet B and returned all but 1 CORE three minutes later. We cannot tell who controls it.

07 · The fee moneyThe service that paid the b14g attacker's fees

Every transaction on the chain costs a small fee, paid in CORE. A brand-new wallet has none, so the attacker needed some first.

Half an hour before the drain, service Y sent wallet A 615.62 CORE. It was the wallet's first and only funding. Odd amounts like that are typical when someone swaps another coin into CORE, though the record cannot show what was swapped.

Later that morning, service Y took in 11.0M of the stolen coins through four deposit addresses and passed it all to MEXC. If service Y is an exchange or a swap service, it may hold a record of the customer who paid for that fee money. It is the clearest lead we found.

08 · The claimsChecking what b14g, Core DAO and X posts said

b14g, Core DAO and posts on X described the theft within hours. In its own post, Core DAO said its network and staking contracts worked normally throughout. We checked each claim against the chain.

One early post on X read the coin count as dollars and overstated the loss about 66 times.

09 · CORE priceCORE price after the b14g hack

The price held steady through the morning. It started to slide minutes after the first stolen coins reached the services, and lost 3% within half an hour.

By the evening it was 8.5% lower than 24 hours earlier. The chart shows when the price moved. It cannot show who sold.

10 · What nextWhat b14g users can watch now

Most of the stolen coins have not moved. Wallet B and the two new wallets have not touched them. Together they hold 70% of the theft, which matches b14g's own figure of 68M "on Core".

The rest reached exchange and service wallets. b14g says exchanges have frozen about 9M of the coins. Freezes happen inside an exchange's own books, so the chain cannot confirm that figure. Two balances stand out. That evening, service X still held 9.34M CORE, and the deposit address our labels tag as Gate.io's had not passed on its coins. The chain cannot show whether either is frozen.

b14g has promised a full post-mortem. It also says the BTC staked through it stays locked on Bitcoin. We did not check the Bitcoin side. For anyone who staked through b14g, wallet B is the one to watch, and it has sent nothing since that morning. The same week, hackers drained Binance, and we traced where that money went in the Binance hack.

11 · How we checkedMethod and limits

We read the drain transaction, its payouts and every later transfer straight from Core's public node, then checked every wallet's balance on the evening of 31 October. Core Scan, Core's block explorer, gave us the lists of transfers for the two services, and we re-read each one on the node. Prices come from CoinGecko.

The exchange wallets are named from Bitquery's labels and from how the coins moved. Our address APIs do the same work on the chains Bitquery covers, and Bitquery runs this kind of tracing for clients through its crypto investigation services.

12 · The addressesWhere to look

These are the wallets and transactions behind this story, each linked to Core Scan, the chain's explorer.

FAQ

Was b14g hacked?

Yes. On the morning of 31 October, one wallet emptied 91 b14g staking orders in a single transaction. It asked to withdraw 0 CORE from each, and Core's staking code reads 0 as everything, so each order paid out in full.

How much was stolen in the b14g hack?

About 97 million CORE, worth $1.47M at the price just before the drain. One early post read the figure as dollars by mistake.

Was Core DAO hacked?

We found nothing wrong with Core itself. Its staking contract did what b14g's orders asked. The fault was in how b14g passed the requests on. Core DAO says coins staked directly with validators, or through other apps, were not touched.

Where are the stolen coins now?

On the evening of 31 October, 70% of them had not moved, most in the attacker's second wallet. The rest went to a Bybit hot wallet and two services that pass coins on to Bybit, Gate.io and MEXC.

Is BTC staked through b14g safe?

b14g says the BTC staked through it stays locked on Bitcoin and was not affected. Bitcoin staked for Core sits in a time lock on the Bitcoin chain, and the theft took CORE only. We did not check the Bitcoin side.

What happened to the CORE price after the b14g hack?

The price fell 8.5% over the 24 hours to the evening of the hack. It started to slide minutes after the first of the loot reached exchange and service wallets.