How much was lost in the SynLev hack?

The SynLev hack resulted in $278K in losses on March 13, 2021.

What attack technique was used in the SynLev exploit?

The SynLev 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.

SynLev Hack

TOTAL LOST $278K

Low Mar 13, 2021 Rugpull ethereum

Affected Chain ethereum Incident surface

Recovered - No recovery reported

All-Time Rank #1174 By amount stolen

Protocol Type Synthetics Target category

Incident Overview

The removeLiquidity() function makes a call of the external function getSharePrice() in vaultHelper contract:

https://etherscan.io/address/0xe0d6b684…fa00f2#code

vaultHelper is a proxy contract with EOA owner - 0xa2e316cb…5c83c4

The owner could set any address as price aggregator in vaultHelper calling proposeVaultPriceAggregator()

A new aggregator (unverified contract) was provided in the transaction:

https://etherscan.io/tx/0xc888619c…7107a6

This hidden aggregator set the share price to 0.

After this, the contract deployer easily withdrew all vault balance with zero share price which can be found in the event log: https://etherscan.io/tx/0x216db3ca…1f0951#eventlog

The contract deployer added liquidity into the contracts multiple times:

https://bloxy.info/txs/references_address/0xa2e316cb…5c83c4?argument=account&signature_id=1315743

https://bloxy.info/txs/calls_from/0xa2e316cb…5c83c4?signature_id=1315634&smart_contract_address_bin=0xff40827e…1440e3

The contract deployer invoked the removeLiquidity() function into the vault contract to withdraw 541.27 and 20.41 ETH onto his wallet at:

https://etherscan.io/tx/0x216db3ca…1f0951

https://etherscan.io/tx/0x5131d999…97fce4

The contract deployer invoked the ethremove() function into the synSales contract to withdraw 152.09 ETH onto his wallet at:

https://etherscan.io/tx/0xec4ba66c…e1602d

The contract deployer invoked the removeLiquidity() function into the other vault contract to withdraw 104.41 ETH onto his wallet at:

https://etherscan.io/tx/0x6afe1ec9…509d8d

The contract deployer invoked the removeLiquidity() function into the other vault contract to withdraw 10.59 ETH onto his wallet at:

https://etherscan.io/tx/0x5c7644f7…764e51

The contract deployer invoked the removeLiquidity() function into the other vault contract to withdraw 24.26 ETH onto his wallet at:

https://etherscan.io/tx/0xe4c8cc92…800397

Incident Report

Protocol / Project SynLev

Date of Incident March 13, 2021

Affected Chain(s) ethereum

Attack Technique Rugpull

Classification Exchange (DEX)

Primary Source View Post-Mortem

Protocol Information

Protocol Type Synthetics

Affected Token SYN

Official Website synlev.com/

Protocol Twitter/X @SynLevdefi

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 ethereum smart contracts and deploy a custom exploit contract

Protocol Analysis Identification of the exploitable vulnerability in SynLev's contract logic - root cause: exchange (dex)

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 SynLev, these are the critical security checks that could have prevented this incident (March 2021).

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://www.cryptonary.com/synlev-price-crashes-by-over-80-in-24…
02
Web Archive https://web.archive.org/web/20201204014302/https://synlev.com/

Threat Assessment

Severity Level

LOW

Attack Vector Rugpull
Root Cause Exchange (DEX)
Year 2021

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