Unsafe MetaData Decoding leading to an entire transaction fail
Description: For function including PerpetualVault.sol::metadata[0] are at risk of malicious attack because if there are no length checks before accessing metadata can result to an "index out of bounds error" for when metadata array is overly short or a transaction fail.
Impact: This can be taken advantage of by malicious off-chain scripts which can feed an empty metadata array and create instances when PerpetualVault.sol::abi.decode() reverts and cause an entire transaction to fail. This can lead to invalid memory access, out-of-bounds reads, or incorrect values being used in calculations.
Proof of Concept:
here below is the code
(uint256 acceptablePrice) = abi.decode(metadata[0], (uint256))
the contract assumes metadata is always a valid uint256. if the metadata is shorter or malformed, it can lead to unexpected behavior. Also per chance, if metadata is supplied by an untrusted source, an attacker can crash the contract or manipulate the decoded value
Expected outcome of the attack
the decoding will fail if metadata is not exactly 32 bytes.
The contract might revert, leading to Denial of service in PerpetualVault.sol::_withdraw()
If unchecked, an attacker might manipulate how PerpetualVault.sol::acceptablePrice is used in further calculations.
Recommended Mitigation:
It is preferable to validate metadata length and add an explicit check, most especially before PerpetualVault.sol::abi.decode().
Lead Judging Commences
Admin is trusted / Malicious keepers
Please read the CodeHawks documentation to know which submissions are valid. If you disagree, provide a coded PoC and explain the real likelihood and the detailed impact on the mainnet without any supposition (if, it could, etc) to prove your point. Keepers are added by the admin, there is no "malicious keeper" and if there is a problem in those keepers, that's out of scope. ReadMe and known issues states: " * System relies heavily on keeper for executing trades * Single keeper point of failure if not properly distributed * Malicious keeper could potentially front-run or delay transactions * Assume that Keeper will always have enough gas to execute transactions. There is a pay execution fee function, but the assumption should be that there's more than enough gas to cover transaction failures, retries, etc * There are two spot swap functionalies: (1) using GMX swap and (2) using Paraswap. We can assume that any swap failure will be retried until success. " " * Heavy dependency on GMX protocol functioning correctly * Owner can update GMX-related addresses * Changes in GMX protocol could impact system operations * We can assume that the GMX keeper won't misbehave, delay, or go offline. " "Issues related to GMX Keepers being DOS'd or losing functionality would be considered invalid."
Suppositions
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