In line with THORChain’s treasury report for Q1 2022 launched on April 1, the chain registered a progress in income regardless of the twofold impression of persistent market sluggishness and extremely unstable geopolitical components. 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 intensive 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 proven 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 crew additionally retains observe of safety incidents within the blockchain area to assist customers higher perceive the safety of various initiatives from the angle of technical safety and mitigate the funding danger. Aiming to enhance the safety standards for the blockchain sector, the CoinEx safety crew has analyzed the safety dangers of THORChain (RUNE). The crew 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 way of evaluation of the contract code and logic of THORChain (RUNE), the CoinEx safety crew 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 fairly customary ERC-20 token. It ought to be famous that other than the ERC-20 interface, THORChain (RUNE) affords a further interface:
In line with transferTo (as proven within the image above), THORChain (RUNE) makes use of tx.origin, which is likely one of the causes behind its safety dangers. Right here, we should always clarify the distinction between tx.origin and msg.sender:
The under image describes what occurs when an everyday deal with calls the sensible contract:
In such instances, msg.sender = account.deal with, and tx.origin = account.deal with, 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.deal with, whereas tx.origin = account.deal with. Due to this fact, tx.origin is sort of a international variable that traverses the complete name stack and returns the deal with of the account that initially despatched the transaction. That is the important thing concern: up to now, virtually all recognized 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 forms of addresses via exterior addresses is basically completely different. The Official Documentation of solidity states {that a} contract deal with should implement a obtain Ether perform earlier than making transfers.
In mild of the options of tx.origin, hackers might construct an Assault contract:
When the Assault contract receives an ETH switch from a consumer, it would “pilfer a goat from a herd” — the contract will steal the consumer’s RUNE tokens within the course of.
Assault No.2: Inside Assault
An Inside Assault is a particular kind of assault. When making an attempt to steal a consumer’s RUNE via an Inside Assault, the hacker must have a medium token. Furthermore, the token should additionally name third-party contracts. In line with the switch data of RUNE on Ethereum, some attackers hacked RUNE via AMP Token transfers.
AMP Token makes use of the ERC-1820 customary to handle Hook registration and study whether or not Hook is registered upon every switch. If Hook has been registered, then the Hook might 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). Specifically, _callPreTransferHooks is for the from deal with, whereas _callPostTransferHooks is for the to handle (i.e. the receiving deal with).
For normal customers, stealing tokens from themselves is pointless. Due to this fact, attackers might 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 are going to illustrate how this name can be utilized to switch a consumer’s RUNE whereas making an AMP Token switch.
Step 1: A name contract is required (as proven under):
Step 2: Deploy the contract to acquire the Assault Deal with.
Step 3: Name the ERC-1820 contract interface (setInterfaceImplementer) to register the interface.
ERC-1820 Deal with: 0x1820a4B7618BdE71Dce8cdc73aAB6C95905faD24
Contract interface: setInterfaceImplementer(deal with toAddr, bytes32 interfaceHash, deal with implementer)
Specifically, toAddr is the receiving deal with of the AMP switch,
interfaceHash为AmpTokensRecipient的hash:
0xfa352d6368bbc643bcf9d528ffaba5dd3e826137bc42f935045c6c227bd4c72a
interfaceHash is the hash of AmpTokensRecipient:
0xfa352d6368bbc643bcf9d528ffaba5dd3e826137bc42f935045c6c227bd4c72a
Implementer is the Assault Deal with obtained in Step 2.
Step 4: Lure a consumer to switch AMP to the toAddr to set off a callback, and steal his RUNE on the identical time.
Assault No.3: Phishing Assault
As its title suggests, in a phishing assault, the attacker guarantees to present away unimaginable advantages to lure customers into performing sure contract operations. Right here, we are going to introduce a standard phishing assault.
Step 1: The attacker points an ERC-20 token, and should write it into any contract interface that includes signatures.
Step 2: Create a buying and selling pair on Uniswap or another swap;
Step 3: Supply airdrops to all customers/addresses who maintain RUNE tokens;
The preliminary work of the phishing assault is principally accomplished via the above these steps. Subsequent, the attacker solely has to attend for customers to commerce on a swap, and customers danger dropping their RUNE as soon as they carry out operations reminiscent of approve, switch, and so forth.
As well as, with the intention to additional confirm the safety danger of THORChain contract code, CoinEx has mentioned with the safety crew from SlowMist and PeckShield, two well-known safety companies within the business. Confirmed by SlowMist and PeckShield, the safety danger talked about above does exist.
Thus far, we now have lined a number of forms of assaults, in addition to the safety dangers that customers are uncovered to.
How ought to the undertaking crew optimize the contract code to make itself safer and shield customers’ belongings?
The one reply is to be cautious about utilizing tx.origin.
How can common customers mitigate dangers and shield their belongings within the face of assaults that appear unavoidable? The CoinEx safety crew affords the next recommendations:
- For Assault No.1: When making a switch, maintain observe of the estimated Fuel consumption. For an everyday ETH switch, a Fuel payment of 21,000 is greater than sufficient. Watch out if the Fuel consumption far exceeds that determine.
- For Assault No.2: Isolate your tokens by adopting completely different wallets. You possibly can retailer completely different tokens in several addresses. Additional warning is required relating to the new pockets deal with 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 all the time been a prime concern within the blockchain sector. All gamers, together with undertaking groups and exchanges, ought to prioritize safety throughout undertaking operation, maintain customers’ belongings protected and safe, and collectively promote the sound progress of the blockchain business.
