PANCAKEHUNNY

DESCRIPTION OF EVENTS

"PancakeHunny aims to provide users the easiest way to join the bandwagon of the DeFi world, built on top of PancakeSwap, giving you the tastiest CAKEs topped with HUNNY. We support the underlying DeFi technology and ecosystem to compound user yields through the Binance Smart Chain (BSC). We have seen a huge surge in DeFi activity in 2020 since the rise of Yield Aggregator projects on different blockchain networks with existing protocols such as MakerDAO, Aave, Compound, and etc. As a Yield Aggregator with a vital role in the yield farming economy, we are leveraging different DeFi protocols and strategies to maximize user profits."

"On 3rd June 2021, at 1:46 UTC. A smart contract was created to exploit the Hunny Minter Smart Contract. The Contract was subsequently executed 91 times." "According to official sources, PancakeHunny on BSC was attacked by hackers, and the hackers made 43 ETH (a total of more than 100,000 US dollars). PancakeHunny forked from PancakeBunny, and the attack suffered this time was similar to PancakeBunny. Hackers obtained a large amount of HUNNY tokens and threw them to the market, causing the price of HUNNY tokens to plummet." "A lot of Hunny tokens [were] minted out and dumped, the hacker has taken out 38.9 ETH."

"Attacker deployed a contract and added 0.5 BNB from an external wallet address: 0x6be5a267b04e9f24cdc1824fd38d63c436be91ab" "This is the sequence of events: (1) wBNB Swap CAKE from PancakeSwap. (2) Sent CAKE to HUNNY Minter Smart Contract. (3) Added CAKE-BNB Liquidity from PancakeSwap. (4) Deposited CAKE-BNB LP tokens to CAKE-BNB Hive. (5) Redeemed HUNNY Rewards. (6) Swap Cake Balance to HUNNY-BNB, increase CAKE Balance as per #2. (7) Exploited and increased 2,281,142.448 HUNNY supply." "Attacker converted all remaining wBNB into ETH and was sent to an external wallet address: 0x2E5Ea63d69b2ed33C869eED58433f0F799E1F7AA"

"Exploiter’s wallet address: 0x0ef50be29c82ecf2158ec1886dc6692a2b0db411" "Total exploited transactions: 100" "Total BNB gained by the attacker: 216 BNB"

"We have stopped the minting process. Hives are all SAFU." "Since the minter was switched off, we were unable to allocate HUNNY profits to the respective Hives."

"None of the Bunny and Bunny fork attacks is a Flash Loan attack. They are Performance Fee Minting Attacks. They just often get amplified/made easier with Flash Loans. These attacks are made possible by one or more logic bugs in the Performance Fee Minting process."

"The core issue is: it’s taking all the wallet balance to create the LP tokens which will later be used for profit calculation and minting. Same old bug as the two of the previous hacks."

"We have taken immediate action to protect our users from any further potential issues that could arise. All Hives are unaffected. Funds are SAFU. The exploit only affects the Prices of Hunny/BNB." "We have since changed the logic behind the HUNNY Minter, whereby it will only mint HUNNY based on the profits received from vaults."

"Due to the nature of the attack, users who have staked in our HUNNY Hive should observe an increase in the profit as well as an increase in the unlocked HUNNY amount. This is because our Minter also distributed more profits to the HUNNY Hive. In short, other than a price dip, our users are actually benefitting from the higher profits (wBNB) gained from Hunny Hive." "We’ve [also] taken the chance to restructure our internal processes. This has made us stronger and more resilient than ever before."

"We'd like to express our gratitude to our partner @WatchPug_ for keeping a lookout for us since our launch. We will continue to strengthen the security of our smart contracts as we have always endeavored."

The PancakeHunny smart contract had an exploit in the rewards mechanism, which allowed the attacker to mint additional Hunny which was not intended.

HOW COULD THIS HAVE BEEN PREVENTED?

There do not appear to have been any assets lost here. The only impact was that the price of the Hunny token dropped.

Check Our Framework For Safe Secure Exchange Platforms

@WatchPug_ Twitter (Jun 17)
@PancakeHunny Twitter (Jun 17)
@PancakeHunny Twitter (Jun 17)
@PancakeHunny Twitter (Jun 17)
Introduction - HunnyFinance (Jun 17)
Pancakehunny Performance Fee Minting Attack Analysis (Jun 17)
Binance Transaction Hash (Txhash) Details | BscScan (Jun 19)
Pancakehunny Preliminary Incident Report (Jun 19)
Pancakehunny Post Mortem Analysis (Jun 19)
SlowMist Hacked - SlowMist Zone (May 18)
blocksec-incidents/2021.md at main · openblocksec/blocksec-incidents · GitHub (Aug 11)

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