How much was lost in the Themis Protocol hack?

The Themis Protocol hack resulted in $370K in losses on June 27, 2023.

What attack technique was used in the Themis Protocol exploit?

The Themis Protocol exploit utilized Flashloan Price Oracle Attack / Flash Loan Attack. Understanding this attack vector is critical for smart contract auditors and developers building secure DeFi protocols.

How can developers prevent similar smart contract attacks?

Preventing smart contract hacks requires a combination of secure coding practices, thorough security audits, and understanding common attack vectors like reentrancy, oracle manipulation, and access control flaws. Smart Contract Hacking (SCH) provides hands-on training to help developers and auditors identify and prevent vulnerabilities before deployment.

Themis Protocol Hack

TOTAL LOST $370K

Low Jun 27, 2023 Flashloan Price Oracle Attack / Flash Loan Attack arbitrum

Affected Chain arbitrum Incident surface

Recovered - No recovery reported

All-Time Rank #1089 By amount stolen

Auditors 1 Prior security audit

Incident Overview

Quick Summary

Themis Protocol suffered a flashloan exploit which leads to a $367,748 USD loss in various assets.

Details of the Exploit

Themis Protocol, an Arbitrum-based lending protocol, fell victim to a flash loan attack. The attacker deployed a malicious contract with unverified source code which allowed them to exploit multiple pools of the Themis Protocol, including tArbWETH, tArbUSDC, tArbARB, tArbWBTC, tArbDAI, and tArbUSDT. The stolen assets were swapped to ETH, USDT, and USDC within the same transaction.

The attacker manipulated prices and gained 94.32 ETH ($178,453), 130,471 USDC, and 58,824 USDT, amassing a total of $367,748. The stolen funds were then bridged to the Ethereum Mainnet and subsequently transferred through TornadoCash.

Block Data Reference

Attacker address:

https://arbiscan.io/address/0xdb73eb48…b9ab33

Malicious contract:

https://arbiscan.io/address/0x05a1b877…964fca

Malicious transaction:

https://arbiscan.io/tx/0xff368294…7403d8

TornadoCash transfer transaction:

https://etherscan.io/tx/0x65551911…98ab3a

This is classified as a Flash Loans Attacks, Oracle Manipulation & Price Manipulation . Compare similar hacks →

Incident Report

Protocol / Project Themis Protocol

Date of Incident June 27, 2023

Affected Chain(s) arbitrum

Attack Technique Flashloan Price Oracle Attack / Flash Loan Attack

Classification Ecosystem / Borrowing and Lending

Primary Source View Post-Mortem

Protocol Information

Protocol Type Lending

Smart Contract Language Solidity

Official Website themis.exchange/

Protocol Twitter/X @ThemisProtocol

Team Anonymous

Source Code Unverified

Market Context at Time of Hack

Token Categories

Ethereum Ecosystem

Protocol Links

What the Attacker Needed to Succeed

Understanding the prerequisites for this type of attack helps auditors identify protocols that are most at risk and helps developers build better defenses.

Technical Knowledge Deep understanding of flashloan price oracle attack / flash loan attack and Solidity and EVM internals

Capital Required Flash loan capital (borrowed atomically, zero upfront cost)

On-Chain Access Ability to interact with arbitrum smart contracts and deploy a custom exploit contract

Protocol Analysis Identification of the exploitable vulnerability in Themis Protocol's contract logic - root cause: ecosystem / borrowing and lending

Execution Speed Precise transaction ordering and timing to exploit the vulnerability within a single atomic block

Obfuscation Plan A strategy to launder and move stolen funds - typically through mixers, cross-chain bridges, or decentralized DEX swaps to resist tracing

What Auditors Should Check

Could this have been caught in audit? Yes — skilled auditors routinely flag Flashloan Price Oracle Attack / Flash Loan Attack vulnerabilities in code review

Audited by PeckShield Inc. — still lost $370K. Prior audits don't guarantee safety, especially after post-audit code changes.

If you're auditing a protocol with similar architecture to Themis Protocol, these are the critical security checks that could have prevented this incident (June 2023).

Verify all logic paths related to Flashloan Price Oracle Attack / Flash Loan Attack are guarded by proper access controls and input validation - see the Flash Loans Attacks attack class for patterns
Audit oracle price feeds for manipulation risks - ensure time-weighted average prices (TWAPs) or multi-source aggregators are used, not spot prices
Review privileged functions (owner, admin, governance) for potential abuse vectors - centralization risks should be documented and bounded with timelocks or multi-sigs

Master these auditing techniques with hands-on labs and real exploit scenarios in the Smart Contract Hacking course.

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Security Audit History

PeckShield Inc. 2022-01-11 Report

Related Attack Classes

The technique used in this hack maps to these vulnerability classes in our security curriculum:

See all Flash Loans Attacks examples →

Flash Loans Attacks Oracle Manipulation & Price Manipulation

Proof-of-Concept Exploits

1 PoC available

poc-exploits - themis protocol

$ Themis Manipulation of prices using Flashloan

On-Chain Evidence & References

Twitter/X Alert https://twitter.com/BeosinAlert/status/1673930979348717570
Twitter/X Alert https://twitter.com/BlockSecTeam/status/1673897088617426946

Sources & References

01
Source 1 https://twitter.com/peckshield/status/1673778002373509121
02
Reference https://twitter.com/peckshield/status/1673778002373509121?s=20

Threat Assessment

Severity Level

LOW

Attack Vector Flashloan Price Oracle Attack / Flash Loan Attack
Root Cause Ecosystem / Borrowing and Lending
Year 2023

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