In response to THORChain’s treasury report for Q1 2022 launched on April 1, the chain registered a development in income regardless of the twofold influence of persistent market sluggishness and extremely unstable geopolitical elements. Public knowledge exhibits that THORChain recorded $2.17 billion in income in Q1 2022. THORChain, acclaimed because the “cross-chain model of UniSwap”, gained a foothold within the cross-chain buying and selling market counting on its distinctive benefits and earned in depth recognition amongst buyers.
Behind all these glamours, THORChain can be deeply troubled by hacking. The chain suffered frequent safety breaches because it was launched on Ethereum, a undeniable fact that casts doubt on its safety. On April 11, THORChain tweeted about phishing assaults, warning customers to not work together with [DeTHOR] or different unknown tokens inside their wallets, which as soon as once more raised issues about its safety points.
Whereas constructing a sound safety system for CoinEx merchandise, the CoinEx safety workforce additionally retains monitor of safety incidents within the blockchain area to assist customers higher perceive the safety of various tasks from the angle of technical safety and mitigate the funding threat. Aiming to enhance the safety standards for the blockchain sector, the CoinEx safety workforce has analyzed the safety dangers of THORChain (RUNE). The workforce hopes that THORChain may be aware and mitigate the next dangers by optimizing the related sensible contract codes. As well as, this text can be a warning for customers, reminding them to be extra conscious of asset safety and keep away from asset losses.
How safe is THORChain (RUNE)?
By means of evaluation of the contract code and logic of THORChain (RUNE), the CoinEx safety workforce has discovered the next dangers:
To start with, let’s take a look at the contract code of THORChain (RUNE):
https://etherscan.io/address/0x3155ba85d5f96b2d030a4966af206230e46849cb#code
We are able to inform that RUNE is a reasonably normal ERC-20 token. It needs to be famous that aside from the ERC-20 interface, THORChain (RUNE) presents an extra interface:
In response to transferTo (as proven within the image above), THORChain (RUNE) makes use of tx.origin, which is among the causes behind its safety dangers. Right here, we must always clarify the distinction between tx.origin and msg.sender:
The beneath image describes what occurs when an everyday tackle calls the sensible contract:
In such circumstances, msg.sender = account.tackle, and tx.origin = account.tackle, which implies that msg.sender is simply the identical as tx.origin.
The next is what occurs when an account calls contract A, and contract A calls contract B:
When contract A calls contract B (as proven above), we are able to inform that msg.sender equals tx.origin in contract A.
Nevertheless, in contract B, msg.sender = contractA.tackle, whereas tx.origin = account.tackle. Due to this fact, tx.origin is sort of a world variable that traverses all the name stack and returns the tackle of the account that initially despatched the transaction. That is the important thing concern: up to now, nearly all identified assaults towards THORChain (RUNE) relate to tx.origin.
Let’s now learn the way attackers steal customers’ RUNE tokens via tx.origin:
Assault No.1: Pilfer a Goat from a Herd
Addresses on Ethereum are divided into exterior addresses and contract addresses. Transferring ETH to those two varieties of addresses via exterior addresses is basically completely different. The Official Documentation of solidity states {that a} contract tackle should implement a obtain Ether operate earlier than making transfers.
In gentle of the options of tx.origin, hackers could construct an Assault contract:
When the Assault contract receives an ETH switch from a person, it can “pilfer a goat from a herd” — the contract will steal the person’s RUNE tokens within the course of.
Assault No.2: Inside Assault
An Inside Assault is a particular kind of assault. When attempting to steal a person’s RUNE via an Inside Assault, the hacker must have a medium token. Furthermore, the token should additionally name third-party contracts. In response to the switch data of RUNE on Ethereum, some attackers hacked RUNE via AMP Token transfers.
AMP Token makes use of the ERC-1820 normal to handle Hook registration and look at whether or not Hook is registered upon every switch. If Hook has been registered, then the Hook will likely be referred to as.
The contract code of AMP Token exhibits that the ultimate implementation of the switch is: _transferByPartition. In the meantime, there are two calls involving transferHook: _callPreTransferHooks (earlier than the switch) and _callPostTransferHooks (after the switch). Particularly, _callPreTransferHooks is for the from tackle, whereas _callPostTransferHooks is for the to handle (i.e. the receiving tackle).
For normal customers, stealing tokens from themselves is pointless. Due to this fact, attackers could exploit _callPostTransferHooks. Let’s now take a look at the codes of _callPostTransferHooks.
IAmpTokensRecipient(recipientImplementation).tokensReceived()
We are able to inform that the one callback that attackers may exploit is IAmpTokensRecipient(recipientImplementation).tokensReceived()
Subsequent, we’ll illustrate how this name can be utilized to switch a person’s RUNE whereas making an AMP Token switch.
Step 1: A name contract is required (as proven beneath):
Step 2: Deploy the contract to acquire the Assault Tackle.
Step 3: Name the ERC-1820 contract interface (setInterfaceImplementer) to register the interface.
ERC-1820 Tackle: 0x1820a4B7618BdE71Dce8cdc73aAB6C95905faD24
Contract interface: setInterfaceImplementer(tackle toAddr, bytes32 interfaceHash, tackle implementer)
Particularly, toAddr is the receiving tackle of the AMP switch,
interfaceHash为AmpTokensRecipient的hash:
0xfa352d6368bbc643bcf9d528ffaba5dd3e826137bc42f935045c6c227bd4c72a
interfaceHash is the hash of AmpTokensRecipient:
0xfa352d6368bbc643bcf9d528ffaba5dd3e826137bc42f935045c6c227bd4c72a
Implementer is the Assault Tackle obtained in Step 2.
Step 4: Lure a person to switch AMP to the toAddr to set off a callback, and steal his RUNE on the similar time.
Assault No.3: Phishing Assault
As its identify suggests, in a phishing assault, the attacker guarantees to present away unimaginable advantages to lure customers into performing sure contract operations. Right here, we’ll introduce a typical phishing assault.
Step 1: The attacker points an ERC-20 token, and should write it into any contract interface that entails signatures.
Step 2: Create a buying and selling pair on Uniswap or every other swap;
Step 3: Provide airdrops to all customers/addresses who maintain RUNE tokens;
The preliminary work of the phishing assault is mainly accomplished via the above these steps. Subsequent, the attacker solely has to attend for customers to commerce on a swap, and customers threat dropping their RUNE as soon as they carry out operations similar to approve, switch, and so on.
As well as, with the intention to additional confirm the safety threat of THORChain contract code, CoinEx has mentioned with the safety workforce from SlowMist and PeckShield, two well-known safety businesses within the trade. Confirmed by SlowMist and PeckShield, the safety threat talked about above does exist.
To date, we now have coated a number of varieties of assaults, in addition to the safety dangers that customers are uncovered to.
How ought to the mission workforce optimize the contract code to make itself safer and shield customers’ property?
The one reply is to be cautious about utilizing tx.origin.
How can common customers mitigate dangers and shield their property within the face of assaults that appear unavoidable? The CoinEx safety workforce presents the next recommendations:
- For Assault No.1: When making a switch, hold monitor of the estimated Gasoline consumption. For an everyday ETH switch, a Gasoline charge of 21,000 is greater than sufficient. Watch out if the Gasoline consumption far exceeds that determine.
- For Assault No.2: Isolate your tokens by adopting completely different wallets. You’ll be able to retailer completely different tokens in several addresses. Further warning is required in relation to the recent pockets tackle provided by exchanges.
- For Assault No.3: Greed is the supply of all evil. Don’t blindly take part in any airdrop occasion.
Safety has at all times been a high concern within the blockchain sector. All gamers, together with mission groups and exchanges, ought to prioritize safety throughout mission operation, hold customers’ property secure and safe, and collectively promote the sound development of the blockchain trade.