ChainBleedv0.1 · open intel
← back to feed·LOGIC2021-12-22 · 4y ago
Incident · SLOWMIST

Visor Finance

Contract Vulnerability
Estimated loss
VERDICT —UNRATED
Verdict pending. Auto-ingested incidents are reviewed before a public verdict is rendered.
▰ METHOD
LOGIC
LOGICBYTECODE CATCHABLEAI SCANNABLE
Root cause

Root-cause analysis not yet published. The incident description below contains all currently available signal — review the attack transaction directly for definitive forensics.

▰ PROOF OF CONCEPT
DEFIHACKLABS
src/test/2021-12/Visor_exp.sol
view forked test on github ↗

Reproducible Foundry test fork from SunWeb3Sec/DeFiHackLabs. Clone the repo, run forge test against the file path above, and replay the exploit against a mainnet fork at the historical block. Use for reproduction only — not for live targets.

Forensic narrative

Uniswap V3 liquidity management protocol Visor Finance was hacked again. Hackers took advantage of the loopholes to withdraw more than 8.8 million VISRs and sold them on Uniswap, causing the VISR tokens to plummet by nearly 95% and profit over 120 ETH through Tornado Cash. Money laundering. According to SlowMist analysis, this attack is due to a flaw in the RewardsHypervisor contract when checking the permissions of the user's recharge, causing the attacker to construct a malicious contract to arbitrarily cast mortgage credentials. Prior to this June, Visor Finance was also hacked and lost more than US$500,000. Attack method (per SlowMist): Contract Vulnerability. Reported loss: 120 ETH.

Primary source
https://medium.com/visorfinance/post-mortem-for-vvisr-staking-contract-exploit-and-upcoming-migration-7920e1dee55a
Sourced from
slowmist
Technical record
chain
protocol
Visor Finance
bug_class
logic
date_occurred
2021-12-22
loss_usd
source_id
sm:visor-finance::2021-12-22
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