Lens Protocol V2 - maanas's results

Lines of code

https://github.com/code-423n4/2023-07-lens/blob/cdef6ebc6266c44c7068bc1c4c04e12bf0d67ead/contracts/FollowNFT.sol#L115-L125

Vulnerability details

Impact

In scenarios where a user fails to unfollow a profile before selling his follow NFT, he could forever be unable to unfollow the profile.

Proof of Concept

A user could sell his follow NFT without unfollowing a profile. If the new owner of the follow NFT doesn't set the user as the operator or doesn't remove the current user from being a follower, the user will forever be unable to unfollow the profile.

An example scenario would be:

1. Follow NFT's of a particular profile gains monetary value and is being sold at high prices.
2. A user following the profile decides to wrap and sell his Follow NFT but fails to unfollow.
3. The user develops a bad relationship with the profile
4. He wants to unfollow but is unable to

Tools Used

Manual Review

Recommended Mitigation Steps

Allow a profile to unfollow even if the user is not the owner of the NFT.

Assessed type

Other

Lines of code

https://github.com/code-423n4/2023-07-lens/blob/cdef6ebc6266c44c7068bc1c4c04e12bf0d67ead/contracts/libraries/MigrationLib.sol#L60

Vulnerability details

Impact

Some profiles cannot be migrated to V2 if their handle tokenId has already been minted.

Proof of Concept

A handle can be minted in the LensHandles contract before a profile that would have the same handle is migrated from V1.

https://github.com/code-423n4/2023-07-lens/blob/cdef6ebc6266c44c7068bc1c4c04e12bf0d67ead/contracts/namespaces/LensHandles.sol#L87-L94

When the profile attempts to migrate, it would revert since the handle tokenId has already been minted. Hence the profile will be unable to migrate to V2.

Tools Used

Manual Review

Recommended Mitigation Steps

Before minting a handle check whether it belongs to a V1 profile.

Assessed type

Other