Beedle - Oracle free perpetual lending

Summary

Lack of minimum value for auctionLength puts users at risk.

Vulnerability Details

As there is no minimum value for auctionLength a pool owner can set it to 1s. Upon a user taking a loan, the pool owner can startAuction wait a second and then seize the collateral and profit.
This is especially a problem as the pool owner could've initially set the auctionLength to a reasonably long time (e.g. 1 day) and upon seeing a user's transaction for a borrow, the pool owner can just front-run it and change auctionLength to 1s. Immediately after the loan is active, the pool owner just has to start the auction and 1s later seize the innocent user's collateral.

Impact

Pool owners can seize innocent user's collateral

Tools Used

Manual review

Recommendations

Implement a minimum value for auctionLength (e.g. 12 hours)