closeTrove never nulls trove.stake

[code423n4]

Lines of code

https://github.com/code-423n4/2023-02-ethos/blob/73687f32b934c9d697b97745356cdf8a1f264955/Ethos-Core/contracts/TroveManager.sol#L1278-L1293

Vulnerability details

// Auditor's note: not 100% sure if this is intentional, but I have reason to believe it's a mistake.

Description

When a trove gets liquidated, its stake gets set to 0 (through _removeStake, called eg here). However, when a trove gets closed gratiously through _closeTrove, the stake is never nulled.

Exploit scenario

Not nulling a stake could cause unforseen consequences if other areas of the code assume that a non-existent (closed) trove doesn't have a stake.

Recommendation

Either ensure all data relating to a trove gets nulled on closure, or provide documentation (code comments) for why th following invariant doesn't hold:

• opening a trove and closing it leaves the system unchanged (except for the order of elements in TroveOwners).

[c4-judge]

trust1995 marked the issue as unsatisfactory:
Out of scope