Unsafe Bridge: Wonder Hero Game Exploited Through Multi-Chain Smart Contract

• Loss was just the equivalent of 750 BNB, but led to the need for relaunching the game.
• WND prices dropped to $0.24 after tokens were sold rapidly on PancakeSwap.

Wonder Hero, a relatively small P2E and NFT game, once again revealed the weakness in bridges between two blockchains. The game noticed anomalous price action of its native token, WND. 

The game has stopped most services and will most probably close until relaunching in another form. The game is still estimating the losses, of which the freefall of WND market prices is just one part. 

We understand that the community is concerned with the sudden WND price drop. Our team is looking into this issue and we will update as soon as we can.

— WonderHero (@Wonderhero_io) April 7, 2022

Wonder Hero issues the HON and WND tokens, which are now stuck on the Polygon side minus the stolen tokens. Essentially, the assets are safe, but cannot operate until the backing is restored in some form and there is a balance between the token amounts on both sides of the smart contract. 

The only two possible scenarios in a bridge hack are for the hacker to return the sum, or for the project to replenish the losses. In the case of ThorChain (RUNE), the funds were returned by a white hat hacker. But the Wormole bridge on Solana and the Ronin-ETH bridge had no such luck, leading to the need to pour in funds and refuel the smart contract.

Can WND Survive the Crash

Wonder Hero hosts its WND tokens on Polygon and Binance Smart Chain. The bridge smart contract had a flaw that allowed an attacker to mint 80M WND tokens on the BSC side. This time, the haul was negligible – the hacker managed to sell the WND on PancakeSwap, while tanking the price and netting only about 750 BNB.

For the game environment and for the future of WonderHero, the hack was a significant blow. Now, the game has stopped its development with a view to resupplying the smart contract and relaunching.

WND started trading in November 2021, reached a peak above $8.96 then had volatile trading and entered a bear market. The final crash brought WND down to $0.24 before trading was stopped. 

WND trading is very slim on Huobi and PancakeSwap, affecting only a few users. Wonder Hero is a mobile turns-based RPG battler.