`LM_PC_KPIRewarder_v1` if bond token has a blocklist and disputer set disputer address to a blocked address, result in DoS

[hats-bug-reporter[bot]]

Github username: @NicolaMirchev Twitter username: EgisSec Submission hash (on-chain): 0x4c23a8b0e13a17a6383ffa4cac3ade98fe84fd37d206399f31df8c4ddcc5bb61 Severity: medium

Description: Description\ In LM_PC_KPIRewarder_v1 an asserter creates assertation to UMA oracle posting KPI data. UMA oracle accepts bond in different currencies, which is used to incertivies disputers and asserters to tell the truth. This defaultCurrency can be USDC/USDT, both of which has a blocklist functionality. The problem here is that if by any chance/mistake asserter has posted wrong info, untrusted diputer is able to dispute the assertation and provide arbitrary address as disputer. This address later recieves the bond reward, if dispute has been successful. The following would result in DoS of UMA settleAssertion function, which result in unreachability of LM_PC_KPIRewarder_v1::assertionResolvedCallback and so the whole LM_PC_KPIRewarder_v1 logic, because it would be impossible to create new assertions, before we have set assertionPending to false.

Attack Scenario\

1. There is a KPI staking module with trusted asserters, who frequently post asserts to UMA
2. Asserter then posts KPI with some data, but after 2 hours, we see that the info is not correct and an expoiter who monitors for unvalid assertations strikes.
3. He opens a dispute, knowing that he will win, because of the wrongness of the data.
4. He set up a blocklisted address as disputer.
5. LM_PC_KPIRewarder_v1 is DoSed and no rewards could be accured, because there is pending assertation stucked

Attachments

1. Proof of Concept (PoC) File Will provide if needed

2. Revised Code File (Optional) Implement some kind of backup logic, which could be opening a new assertation asserting Contract is stucked, because assertion {id} could not be proceed. The following could be opened by Asserter, only if assertionPending = true and when it is resolved, it should make back assertionPending = false

[0xdeth]

@PlamenTSV @0xmahdirostami

Can you please add a label for this issue, so the sponsors don't miss it?

Thanks.