DeFi aggregator raided by five hackers on launch day

Fledgling decentralized finance, or DeFi, protocol ForceDAO has had a rough start, with several incursions from hackers taking place just hours after it launched.

The Ethereum-based yield aggregator had only just launched its airdrop campaign on April 3 when four malicious “black hat” hackers managed to drain a total of 183 Ether (ETH), worth approximately $367,000 at the time. One friendly "white hat" hacker assisted the team by alerting them to prevent further losses.

The team has released a post-mortem report of the attacks and taken responsibility for what it termed an “engineering oversight.”

POST-MORTEMTo the Force and DeFi community, we'd like to share a post-mortem on the recent xFORCE exploit.Thanks to everyone technical and non-technical who helped along the way.Especially to the White Hat who helped deter FORCE getting drained.https://t.co/MK2GH69yLd

— Force (@force_dao) April 4, 2021

Following the incursion, the team made a decision to transfer 60 million FORCE tokens from the treasury multisignature wallet into a deployer wallet to create and execute three votes that would effectively burn the FORCE balances in three of the hackers’ addresses.

The post-mortem explained that the xFORCE platform affected was a fork of a SushiSwap smart contract containing a mechanism to revert tokens in the event of failed transactions. The protocol describes xFORCE as the “interest-bearing” version of FORCE, representing shares in its pools similar to how liquidity provider tokens work.

A flaw in the contract used by ForceDAO enabled the attackers to exploit this mechanism to mint xFORCE tokens, which were then withdrawn and exchanged for ETH on the markets. The team acknowledged the attack would have been relatively easy to prevent.

“This could’ve been prevented by using a standard Open Zeppelin ERC-20 or adding a safeTransferFrom wrapper in the xSUSHI contract.”

It added that the hack was currently under investigation, as some of the addresses originated from the popular exchanges FTX and Binance. A snapshot will be taken, and the project will be relaunched with a new xFORCE token, it added.

Following the launch and airdrop, the price of FORCE surged to over $2 on Apr. 4 but has since crashed over 95% to $0.05 at the time of writing.