Cetus suffered attacks leading to huge losses, analysis of attack methods and fund flow.

On May 22, the liquidity provider Cetus on the SUI ecosystem reportedly suffered an attack, with multiple trading pairs experiencing significant declines, estimated losses exceeding $230 million. Cetus subsequently announced that it has suspended its smart contracts and is investigating the incident.

The security team quickly intervened to analyze the situation. Below is a detailed analysis of the attack methods and the funds transfer situation.

Attack Analysis

Attackers exploit overflow vulnerabilities by carefully crafting parameters to bypass detection, exchanging a minuscule amount of tokens for a massive amount of liquidity assets. The specific steps are as follows:

1. The attacker borrowed a large amount of haSUI through a flash loan, causing the pool price to plummet by 99.90%.

2. Open liquidity positions in a very narrow price range, with a width of only 1.00496621%.

3. Claims to add a large amount of liquidity but only actually pays 1 token. This is the core of the attack, exploiting a vulnerability in the overflow detection of checked_shlw in the get_delta_a function.

4. The system misjudges the required number of tokens, allowing attackers to exchange a small number of tokens for a large amount of liquidity assets.

5. The attacker removed liquidity, obtaining a huge token profit, ultimately netting approximately 10 million haSUI and 5.76 million SUI.

Project Party Repair Status

Cetus has released a fix patch, mainly correcting the checked_shlw function:

• Correct the error mask to the correct threshold
• Adjust judgment conditions
• Ensure correct detection of overflows that may be caused by left shifts.

Capital Flow Analysis

Attackers profited approximately $230 million, including various assets such as SUI, vSUI, and USDC. Some funds were transferred to EVM addresses through cross-chain bridges. The specific flow is as follows:

• Approximately $10 million deposited into Suilend
• 24 million SUI transferred to the new address, not yet transferred out.
• Transfer USDC, SOL, suiETH, etc. to EVM addresses through cross-chain bridges.
• The funds on the EVM address are partially exchanged for ETH.
• 20000 ETH transferred to new address

Currently, the SUI Foundation claims to have successfully frozen $162 million of stolen funds.

Summary

This attack fully demonstrates the dangers of mathematical overflow vulnerabilities. Developers should strictly validate all boundary conditions of mathematical functions in smart contract development to prevent similar attacks.