“Payzero” Scams and The Evolution of Asset Theft in Web3

In this entry, we discuss a Web3 fraud scenario where scammers target potential victims via fake smart contracts, and then take over their digital assets, such as NFT tokens, without paying. We named this scam “Payzero”...

Use reentrancyGuard for safeTransferFrom

Lines of code Vulnerability details Impact A reentrancy guard is a mechanism used to prevent reentrant calls in smart contracts, which can be a security vulnerability. Reentrancy can happen when a malicious contract calls the "safeTransferFrom" function and then calls it again before the first ca...

limits are not correctly enforced in withdrawHook contract

Lines of code Vulnerability details Impact withdrawHook contract checks that inside a specified length of time only certain amount of withdrawal are possible per user and globally. But on every period reset the allowed withdraw limit check is missing. And a user can withdraw more that is allowed...

POSSIBLE FRONTRUNNING ATTACK ON MINTING LONG/SHORT POSITIONS

Lines of code Vulnerability details Impact createMarket function in PrePOMarketFactory.sol contract creates a new PrePOMarket contract. Salt is used for creating the contract which is computed from createPairTokens function. Variables passed to this function are visible from anyone they are input...

Long and short tokens can continue to be minted even after expiry

Lines of code Vulnerability details Impact Users can mint after expiry but before the final price has been set Proof of Concept function mintuint256 amount external override nonReentrant returns uint256 requirefinalLongPayout MAXPAYOUT, "Market ended"; requirecollateral.balanceOfmsg.sender =...

function mint() in PrePOMarket shouldn't accept deposits after expiryTime of Market

Lines of code Vulnerability details Impact Function mint Mints Long and Short tokens in exchange for amount collateral and according to the comment in the IPrePOMarket: "Minting is not allowed after the market has ended." but there is no check or restriction in the code that to make sure minting ...

Infinite approval given to DepositTradeHelper contract can be misused by malicious actors

Lines of code Vulnerability details Impact depositAndTrade function in DepositTradeHelper account has infinite approval to spend baseTokens & collateralTokens of user using offChain signatures. However, once swapRouter executes UniV3 swap transaction on line 33, the contract does not give up its...

[NAZ-M2] Usage of send() Can Result In Revert

Lines of code Vulnerability details Impact Several functions are sendusing is used by the across several functions to transfer ETH/WETH. send uses a fixed amount of gas, which was used to prevent reentrancy. However this limit your protocol to interact with others contracts that need more than th...

Redeem should revert if the TokenSender.sol doesn’t have enough outputtoken to reimburse to users.

Lines of code https://github.com/prepo-io/prepo-monorepo/blob/49a7ed94272db013245d9364e69be713a8aef0a2/apps/smart-contracts/core/contracts/TokenSender.solL41 Vulnerability details According to the comments in the code of RedeemHook.hook function : Once a market has ended, users can directly settl...

DoS on relayCalls when the nonce variable reach type(uint256).max

Lines of code Vulnerability details Impact Denial of service on relayCalls functions when the nonce variable reach typeuint256.max Proof of Concept When the smart contracts start to be used, the variable in storage nonce will start to increment by 1, and since the nonce variable cannot be...

There is no re-register o re-assign function

Lines of code Vulnerability details Impact There is no re-register or re-assign option for the smart contracts. Let's assume a smart contract is registered either through the register function with a new NFT minted or the assign function to an existing NFT. However, if somehow, the NFT is burned ...

PostTxProcessing can revert user transactions not interacting with Turnstile

Lines of code Vulnerability details Impact Any transaction, even those that don't interact with the Turnstile contract, can be reverted by the PostTxProcessing hook if there was a CSR specific error. Thus, the CSR module can impair the behavior of smart contracts not related to the module. Proof ...

Use of transfer() instead of call() to send eth

Lines of code Vulnerability details Use of transfer instead of call to send eth Impact Use of transfer might render ETH impossible to withdraw because after istanbul hardfork, there is increases in the gas cost of the SLOAD operation and therefore breaks some existing smart contracts. Those...

We Need Smarter Smart Contracts To Prevent DeFi Hacks

By Waqas The smart contracts that govern DeFi are littered with exploitable code, and hackers understand that since hundreds of millions of crypto funds have been siphoned off due to this very issue. This is a post from HackRead.com Read the original post: We Need Smarter Smart Contracts To Preve...

Critical Flaw Reported in Move Virtual Machine Powering the Aptos Blockchain Network

Researchers have disclosed details about a now-patched critical flaw in the Move virtual machine that powers the Aptos blockchain network. The vulnerability "can cause Aptos nodes to crash and cause denial of service," Singapore-based Numen Cyber Labs said in a technical write-up published earlie...

Ankr Launches Chainscanner Blockchain Explorer Tool

By Waqas The Chainscanner is available for free on the Ankr website, allowing users to search for transaction data, addresses, smart contracts, and much more. This is a post from HackRead.com Read the original post: Ankr Launches Chainscanner Blockchain Explorer Tool...

Upgraded Q -> M from 696 [1666361742731]

Judge has assessed an item in Issue 696 as Medium risk. The relevant finding follows: L05 - Usage of trasfer over call to send Ether could cause unexpected Reverts payablepayAddress.transferpayAmt; // royalty transfer to royaltyaddress The function payEther sends ether via transfer which passes a...

Regulating DAOs

In August, the US Treasurys Office of Foreign Assets Control OFAC sanctioned the cryptocurrency platform Tornado Cash, a virtual currency "mixer" designed to make it harder to trace cryptocurrency transactions--and a worldwide favorite money-laundering platform. Americans are now forbidden from...

Crypto Trading Firm Wintermute Loses $160 Million in Hacking Incident

In what's the latest crypto heist to target the decentralized finance DeFi space, hackers have stolen digital assets worth around $160 million from crypto trading firm Wintermute. The hack involved a series of unauthorized transactions that transferred USD Coin, Binance USD, Tether USD, Wrapped...

Elrond-go has improper initialization

Impact Read only calls between contracts can generate smart contracts results. For example, if contract A calls in read only mode contract B and the called function will make changes upon the contract's B state, the state will be altered for contract B as if the call was not made in the read-only...