| title |
Ronin Bridge |
| description |
Compromising validator keys to authorize malicious withdrawals |
| type |
Exploit |
| network |
|
| date |
2022-03-23 |
| loss_usd |
624000000 |
| returned_usd |
0 |
| tags |
|
| subcategory |
|
| vulnerable_contracts |
0x1A2a1c938CE3eC39b6D47113c7955bAa9DD454F2 |
|
| tokens_lost |
|
| attacker_addresses |
0x098B716B8Aaf21512996dC57EB0615e2383E2f96 |
|
| malicious_token |
|
| attack_block |
|
| reproduction_command |
forge test --match-contract Exploit_RoninBridge -vvv |
| attack_txs |
0xc28fad5e8d5e0ce6a2eaf67b6687be5d58113e16be590824d6cfa1a94467d0b7 |
0xed2c72ef1a552ddaec6dd1f5cddf0b59a8f37f82bdda5257d9c7c37db7bb9b08 |
|
| sources |
| title |
url |
Ronin Writeup |
tps://roninblockchain.substack.com/p/community-alert-ronin-validator |
|
|
|
- Social engineer attack against key holders to get privileged keys
- Use the privileged keys to drain funds
The Ronin Bridge was operated by 9 validators with a threshold of 5 out of the 9. This threshold was misleading though, as 4 validators were operated by Sky Mavis. What is more: in Nov 2021, Axie delegated their validator's signature to Sky Mavis too. This delegation was supposed to be temporary, as Axie was experiencing heavy traffic. Nevertheless, it was never revoked.
As a result, Sky Mavis had 5 signatures. Enough to approve any message.
The attacker got control of the keys doing a social-engineer attack. Once they had it, the were able to call withdrawERC from the bridge without a backing transaction on the other side.
- Multisigs do not matter if in practice several keys are controlled by the same entity. Distribute keys to independent entities to actually enforce that several entities must agree with a transaction before executing it.
- Wormhole Bridge - Bridge vulnerability through uninitialized guardian set
- Polynetwork Bridge - Hijacking bridge validator roles via sighash collision
- Nomad Bridge - Bridge message validation bypass through faulty initialization
