How much was lost in the ArbTomb hack?

The ArbTomb hack resulted in $115K in losses on April 18, 2023.

What attack technique was used in the ArbTomb exploit?

The ArbTomb exploit utilized Rugpull. 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.

ArbTomb Hack

TOTAL LOST $115K

Low Apr 18, 2023 Rugpull

Affected Chain 2023 Incident surface

Recovered - No recovery reported

All-Time Rank #1479 By amount stolen

Protocol Type Exit Scam/Rugpull Target category

Incident Overview

Quick Summary

ArbTomb project was rugged by the $xToken deployer, resulting in the loss of 114,646 $USD worth of ETH.

Details of the Exploit

On the day of its genesis launch, ArbTomb project experienced a rugpull on the Arbitrum layer-two chain. The attack affected ParbRewardPool contract which had $xToken as one of its assets. The attacker exploited their privilege over contracts by minting 1,000,000,000,000,000 $xTokens and transferring them into the pool since they were also deployers for this token's contract.

The exploit involved unverified source code for $xToken which allowed malicious actors to drain funds from the pool such as $WETH, $USDC, $ARB, and $SUSHI tokens. After gaining access to these funds the scammer swapped all stolen assets for 54.75 $ETH before bridging it onto Ethereum mainnet.

After that point, they used TornadoCash mixer service to move around some part (52 $ETH)of stolen funds before sending the rest (2.43$ ETH) directly to Binance hot wallet address.

Block Data Reference

Scammer address:

https://arbiscan.io/address/0x2b899942…ec81ef

Stolen funds holder address:

https://arbiscan.io/address/0x2781d100…A212E6

Malicious transaction:

https://arbiscan.io/tx/0xa54485cf…258f26

Bridging transaction:

https://arbiscan.io/tx/0x3809350b…f2782b

Malicious contract:

https://arbiscan.io/address/0x38f26758…8c5c8b

Incident Report

Protocol / Project ArbTomb

Date of Incident April 18, 2023

Attack Technique Rugpull

Classification Token

Primary Source View Post-Mortem

Protocol Information

Protocol Type Exit Scam/Rugpull

Affected Token PARB

Protocol Twitter/X @Arb_tomb

Team Anonymous

Source Code Unverified

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 rugpull and Solidity and EVM internals

Capital Required Seed capital to cover gas and initial position setup

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

Protocol Analysis Identification of the exploitable vulnerability in ArbTomb's contract logic - root cause: token

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? Hard to catch — private key / OpSec failures are outside smart contract audit scope

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

Verify all logic paths related to Rugpull are guarded by proper access controls and input validation
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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Sources & References

01
Source 1 https://twitter.com/PeckShieldAlert/status/1648243679130439682?s=20

Threat Assessment

Severity Level

LOW

Attack Vector Rugpull
Root Cause Token
Year 2023

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