Bid Function Allows Bidding at the Exact Auction End Time
Summary
See below
Vulnerability Details
In the FjordAuction contract, the bid function allows users to place bids as long as the current time is not strictly greater than the auction end time (auctionEndTime). The relevant code snippet is:
The condition block.timestamp > auctionEndTime means that users can still place bids if the current timestamp is exactly equal to auctionEndTime. The purpose of the bid function is to accept bids only before the auction ends, but this implementation allows bids to be placed at the exact end time of the auction, which may not be the intended behavior.
Impact
This behavior could lead to unexpected last-second bids being accepted at the exact end time of the auction, potentially disrupting the auction process and fairness.
Tools Used
Manual
Recommendations
To ensure that no bids are accepted at or after the auction end time, modify the condition to:
Lead Judging Commences
Users can bid in the same block when the actionEnd could be called (`block.timestamp==actionEndTime`), depending on the order of txs in block they could lose funds
The protocol doesn't properly treat the `block.timestamp == auctionEndTime` case. Impact: High - There are at least two possible impacts here: 1. By chance, user bids could land in a block after the `auctionEnd()` is called, not including them in the multiplier calculation, leading to a situation where there are insufficient funds to pay everyone's claim; 2. By malice, where someone can use a script to call `auctionEnd()` + `bid(totalBids)` + `claimTokens()`, effectively depriving all good faith bidders from tokens. Likelihood: Low – The chances of getting a `block.timestamp == auctionEndTime` are pretty slim, but it’s definitely possible.
Prize pool breakdown
Live
The contest is live. Earn rewards by submitting a finding.
Appeals
This is your time to appeal against judgements on your submissions.
Appeals Review
Appeals are being carefully reviewed by our judges.