Submission Details
Severity:
signed messages can be replayed
Summary
signed messages can be replayed when sending to the bridge.
Vulnerability Details
withdrawTokensToL1() and sendToL1() don't use nonces. So the same valid signed message along with v, r and s can be submitted again to replay the operation (as everything can be seen publicly in the mempool). ECDSA.recover() will obviously return the same signer every time which is valid. If the operation being replayed is sending funds out, then the bridge could be drained.
Impact
This could drain the bridge from all funds.
Tools Used
Manual review.
Recommendations
Add a nonce to the signed message.
Updates
Lead Judging Commences
0xnevi almost 2 years ago
Submission Judgement Published Assigned finding tags:
withdrawTokensToL1()/sendToL1(): signature replay
Rewards breakdown
nSLOC
99This contest has a flat reward structure with the following payouts:
100 EXP
20 EXP
2 EXP
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