Visor Finance Arbitrage Attack

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Visor Finance

Visor Finance liquidity pool suffered from an arbitrage attack, which drained at least $773k of funds. The team has promised upgrades to the smart contract hot wallet and all funds will be reimbursed.

This is a global/international case not involving a specific country.

About Visor Finance

"Visor Finance is a Uniswap based protocol that is specialized in NFT smart vaults for liquidity provisioning. It predicts the DeFi ecosystem where market conditions can unlock liquidity from networks of independent smart vaults."

"Visor allows DeFi participants to utilize NFT Smart Vaults for liquidity provisioning and active liquidity management on Uniswap v3." "Visor's community is thousands strong and is distributed across a variety of channels."

"As @uniswap v3 makes liquidity provision more complicated for the common man, @VisorFinance allows you to compete with professional liquidity providers by pooling peoples liquidity together and dynamically concentrating it around price to maximize returns for you."

"On Thursday, Nov 25th 1:18pm UTC an economic attack was carried out on Visor's OHM-ETH 1% LP management contract by a malicious contract. Users funds were secured in full and deposit caps lowered were to put a hold on new deposits until a deposit proxy is deployed into production."

"Hello, one of DeFi's oldest exploits - Trusting spot price of a DEX." "The underlying issue is their reliance on spot prices for issuing shares. The spot price can be manipulated." "Price manipulation is a classic economic exploit. Visor relied on floating deposit caps and total supply caps to mitigate this possibility by prohibiting large single-sided deposits and large shares of LP tokens to be minted at once." "While this has been sufficient for pools like WBTC-ETH 0.3% where liquidity distribution is deep and symmetric, it can only go so far at safeguarding pools offering steep gradient opportunities for (relatively) cheap tick traversal."

"Everyone is thirsty for drama, here are the facts: No funds at risk, all users are safe. No smart contract bug. No operational security exploit. It was Uniswap v3 economic arbitrage. The arbitrage resulted in minor treasury assets lost for Visor and in test positions." "This process was repeated in 2 additional instances, with diminishing returns until the profitable liquidity gradient was exhausted." "It is interesting to note that a potential second attacker, what appears to be a generalized MEV bot, conducted a similar attack in between the second and third instances of the attack, in block 1368725."

"Visor’s test hypervisors without the usual individual and global caps function as bounties for arbitragers to exploit positions. This has only strengthened our conviction in the current safeguards and necessary restrictions at the contract level on public and private hypervisors."

"While we cannot see the contract code, it is easy to understand that the attack vector relied on large swaps to manipulate the Uniswap V3 pool's current price. Given the steep gradient in the liquidity distribution of this pair, we see that it is an attractive candidate for price manipulation, as after an initial threshold where liquidity is highly concentrated, impacting the price requires a relatively small amount of assets."

"Due to the composable nature of Visor's management contracts, deposit proxies can be deployed and permissioned as gatekeepers. Varieties of these proxies have been used consistently in the past when deposit restrictions were desired."

"The team will be deploying such proxy into production in the coming days and resume deposits."

"User funds were lost in the first incident but will be reimbursed. The rest of the pools were apparently test pools with only team funds (100k+)."

This is a global/international case not involving a specific country.

The background of the exchange platform, service, or individuals involved, as it would have been seen or understood at the time of the events.

Include:

• Known history of when and how the service was started.
• What problems does the company or service claim to solve?
• What marketing materials were used by the firm or business?
• Audits performed, and excerpts that may have been included.
• Business registration documents shown (fake or legitimate).
• How were people recruited to participate?
• Public warnings and announcements prior to the event.

Don't Include:

• Any wording which directly states or implies that the business is/was illegitimate, or that a vulnerability existed.
• Anything that wasn't reasonably knowable at the time of the event.

There could be more than one section here. If the same platform is involved with multiple incidents, then it can be linked to a main article page.

The Reality

This sections is included if a case involved deception or information that was unknown at the time. Examples include:

• When the service was actually started (if different than the "official story").
• Who actually ran a service and their own personal history.
• How the service was structured behind the scenes. (For example, there was no "trading bot".)
• Details of what audits reported and how vulnerabilities were missed during auditing.

What Happened

The specific events of the loss and how it came about. What actually happened to cause the loss and some of the events leading up to it.

Key Event Timeline - Visor Finance Arbitrage Attack

Date	Event	Description
November 25th, 2021 12:00:00 AM	Main Event	Expand this into a brief description of what happened and the impact. If multiple lines are necessary, add them here.

Total Amount Lost

The total amount lost has been estimated at $773,000 USD.

How much was lost and how was it calculated? If there are conflicting reports, which are accurate and where does the discrepancy lie?

Immediate Reactions

How did the various parties involved (firm, platform, management, and/or affected individual(s)) deal with the events? Were services shut down? Were announcements made? Were groups formed?

Ultimate Outcome

What was the end result? Was any investigation done? Were any individuals prosecuted? Was there a lawsuit? Was any tracing done?

Total Amount Recovered

There do not appear to have been any funds recovered in this case.

What funds were recovered? What funds were reimbursed for those affected users?

Ongoing Developments

What parts of this case are still remaining to be concluded?

Prevention Policies

Which policies could have prevented this event from happening?