ThorChain Origin Flaw Airdrop Scam

Notice: This page is a freshly imported case study from the original repository. The original content was in a different format, and may not have relevant information for all sections. Please help restructure the content by moving information from the 'About' section to other sections, and add any missing information or sources you can find. If you are new here, please read General Tutorial on Wikis or Anatomy of a Case Study for help getting started.

Notice: This page contains sources which are not attributed to any text. The unattributed sources follow the initial description. Please assist by visiting each source, reviewing the content, and placing that reference next to any text it can be used to support. Feel free to add any information that you come across which isn't present already. Sources which don't contain any relevant information can be removed. Broken links can be replaced with versions from the Internet Archive. See General Tutorial on Wikis, Anatomy of a Case Study, and/or Citing Your Sources Guide for additional information. Thanks for your help!

ThorChain

The ThorChain smart contract used tx.origin to validate that a transfer of RUNE tokens originated from the right wallet. However, if the user interacted with another smart contract, which performed the transfer, the tx.origin would originate from them, and the transaction would go through as though they had sent it.

A malicious hacker was airdropping a smart contract token which would initiate a transfer whenever the token was sent or otherwise interacted with, which would drain any RUNE tokens present in that wallet.

As a result, $76k (or more) worth of RUNE was stolen from users. There doesn't appear to have been any way to assist affected users set up.

This is a global/international case not involving a specific country.

About ThorChain

"THORChain (RUNE) [is] a decentralized cross-chain transaction protocol." "Creating a secure cross-chain bridge is one of the most important milestones for the industry right now, and the race is on to be the first to provide it." "Founded in 2018, THORChain is a cross-chain exchange that facilitates transactions between the Binance, Ethereum, and Bitcoin blockchains, aiding in a difficult problem of inter-blockchain swaps without being compelled to pay sizable fees each time. This represents a tremendous pain point and the efforts of THORChain have been well-received, pushing up a token from a low of $0.00851264, two years ago, to a high of $20.89 two months ago." "THORChain entered into its guarded “Chaosnet” launch during April, facilitating cross-chain swaps across the Bitcoin, Ethereum, Litecoin, Bitcoin Cash and Binance Chain networks."

"THORChain don't have assets synthetically tied to a price using an oracle, rather arbitrage trading bots and individuals, seeking to squeeze a profit from the price differences of an individual cryptocurrency on different blockchains, keep the liquidity pool's volume high in the midst of regularly large price swings. Passive liquidity providers earn a steady stream of rewards, often representing an APR of 10%+, even after technical considerations like "impermenant loss" that chips away at total return if the tokens, when removed from the liquidity pool, that aren't at 100% at the same radio value as when you first staked them."

"THORChain (RUNE) claims that hackers airdrop UniH tokens to Ethereum addresses as bait to steal RUNE tokens in users' wallets. Hackers have airdropped UniH tokens with malicious contracts to at least 76,000 Ethereum addresses. Once receiving users sell their newly received UniH tokens (or even just approve the sale) on decentralized trading platforms such as Uniswap, the hackers will They can steal any RUNE tokens they have in their wallets. This is because the RUNE token uses a non-standard token contract called "tx.origin". According to Thorchain’s RUNE token contract code “Beware of phishing contracts that may steal tokens by intercepting tx.origin”, it knows that this type of attack may occur."

"Someone is airdropping UniH tokens to ETH ad[d]resses. Just ignore : do not exchange them on UniSwap. If you approve it for swap[p]ing, the contract will drain your wallet."

"Any contract call can drain all your RUNE, no need for approvals or anything. (1) User calls the contract. (2) The contract calls RUNE.transferTo and transfers everything out. That's it, no need for approvals or anything."

"Solidity has a global variable, tx.origin which contains the address of the account that originally sent the call (or transaction). In old days of Solidity, this was used as a way to make sure only a EOA (Externally Owned Account) can make calls to certain functions. So how does it differ from msg.sender? Let's consider following scenario. If account A calls contract B, and B calls contract C, in C msg.sender is contract B and tx.origin is account A." "Contracts that authorize users using the tx.origin variable are typically vulnerable to phishing attacks that can trick users into performing authenticated actions on the vulnerable contract." "That's [a] well known attack vector but sadly $RUNE was still using tx.origin for approve and call method."

"Solution to this would be using ERC20Permit to have approve and transfer done in one call. Check this great article if you want to know more about Permit." "If you think using tx.origin for authentication is a great idea, think twice and read this article again, and again. I don't recommend using tx.origin anywhere in the code and if your current system is using this global variable, please stop everything and refactor your code. You don't want to end up on the news as next protocol which got rekt."

"In just a few hours, hackers have stolen USD 76,000 worth of tokens."

This is a global/international case not involving a specific country.

The background of the exchange platform, service, or individuals involved, as it would have been seen or understood at the time of the events.

Include:

• Known history of when and how the service was started.
• What problems does the company or service claim to solve?
• What marketing materials were used by the firm or business?
• Audits performed, and excerpts that may have been included.
• Business registration documents shown (fake or legitimate).
• How were people recruited to participate?
• Public warnings and announcements prior to the event.

Don't Include:

• Any wording which directly states or implies that the business is/was illegitimate, or that a vulnerability existed.
• Anything that wasn't reasonably knowable at the time of the event.

There could be more than one section here. If the same platform is involved with multiple incidents, then it can be linked to a main article page.

The Reality

This sections is included if a case involved deception or information that was unknown at the time. Examples include:

• When the service was actually started (if different than the "official story").
• Who actually ran a service and their own personal history.
• How the service was structured behind the scenes. (For example, there was no "trading bot".)
• Details of what audits reported and how vulnerabilities were missed during auditing.

What Happened

The specific events of the loss and how it came about. What actually happened to cause the loss and some of the events leading up to it.

Key Event Timeline - ThorChain Origin Flaw Airdrop Scam

Date	Event	Description
July 23rd, 2021	Main Event	Expand this into a brief description of what happened and the impact. If multiple lines are necessary, add them here.

Technical Details

This section includes specific detailed technical analysis of any security breaches which happened. What specific software vulnerabilities contributed to the problem and how were they exploited?

Total Amount Lost

The total amount lost has been estimated at $76,000 USD.

How much was lost and how was it calculated? If there are conflicting reports, which are accurate and where does the discrepancy lie?

Immediate Reactions

How did the various parties involved (firm, platform, management, and/or affected individual(s)) deal with the events? Were services shut down? Were announcements made? Were groups formed?

Ultimate Outcome

What was the end result? Was any investigation done? Were any individuals prosecuted? Was there a lawsuit? Was any tracing done?

Total Amount Recovered

There do not appear to have been any funds recovered in this case.

What funds were recovered? What funds were reimbursed for those affected users?

Ongoing Developments

What parts of this case are still remaining to be concluded?

Individual Prevention Policies

No specific policies for individual prevention have yet been identified in this case.

For the full list of how to protect your funds as an individual, check our Prevention Policies for Individuals guide.

Platform Prevention Policies

Policies for platforms to take to prevent this situation have not yet been selected in this case.

For the full list of how to protect your funds as a financial service, check our Prevention Policies for Platforms guide.

Regulatory Prevention Policies

No specific regulatory policies have yet been identified in this case.

For the full list of regulatory policies that can prevent loss, check our Prevention Policies for Regulators guide.