Xave Finance Hack

Reported loss $0
Ethereum
Other

What happened

On October 8, 2022, an attacker took over contracts owned by Xave Finance, formerly HaloDAO, and minted 100,000,000,000,000 RNBW (100 trillion) to their own address, inflating the token's supply and crashing its price.

Xave's Gnosis Safe multisig had a SafeSnap DaoModule enabled. The module forwards any proposal approved through a Reality.eth question, and the Safe executes it. The module still had default settings: questionCooldown and minimumBond were both 0. Anyone could post a proposal, answer it themselves at no bond, and execute it with no delay for the multisig to react.

The attacker's proposal minted the RNBW and moved ownership of the RNBW token, the LPOP token and the PrimaryBridge contract to the attacker. Beosin reported that the minted RNBW was converted into xRNBW and held at the attacker's address. One incident review puts the realized loss at about $635, because RNBW liquidity was thin. Xave's team later took mitigation steps on its V2 contracts.

Attacker: 0x0f44f3489d17e42ab13a6beb76e57813081fc1e2 Attack contract: 0xe167cdaac8718b90c03cf2cb75dc976e24ee86d3 Exploit transaction: 0xc18ec2eb7d41638d9982281e766945d0428aaeda6211b4ccb6626ea7cff31f4a

How it happened

  1. The attacker created a Reality.eth question for a proposal of four transactions: mint 100 trillion RNBW to the attacker, and call transferOwnership to the attacker on the RNBW token, the LPOP token and PrimaryBridge.
  2. The attacker answered the question in favor. With minimumBond at 0 there was no meaningful bond to stake or lose, and nobody challenged it.
  3. The attacker registered the proposal on the DaoModule with addProposalWithNonce, 9 blocks before the exploit.
  4. Once the answer was final, the attack contract called executeProposalWithIndex in transaction 0xc18ec2eb.... With questionCooldown at 0, the module forwarded all four calls to the Xave Safe, which executed them because it trusted the module.
  5. The attacker received the 100 trillion RNBW and ownership of the three contracts.

Protocol details

Classification Token / Governance
Protocol Type DEX
Affected asset / contract RNBW
Implementation language Solidity
Protocol links Website @XaveFinance

Security review history

Evidence

Same attack technique

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