Incident Overview
Bondly Finance suffered a hack on July 15, 2021. The attacker was able to mint 373 million BONDLY tokens and profited for 6,800,987 USD
The attacker's address:
https://etherscan.io/address/0xc433d50d…0d25e8
The owner (0x58a058ca…d3330c) of StakingReward contract (0x6bee9387…a598d1) was compromised and the owner had an allowance on sending BONDLY tokens:
function send(address to, uint256 amount) onlyOwner nonReentrant external {
require(sent.add(amount) sent = sent.add(amount);
bondToken.transfer(to, amount);
}
The contract owner sent tokens to the attacker's address at:
https://etherscan.io/tx/0xc2b33946…1cfaae
The attacker used received tokens to mint 200,460,00 zenBONDLY on the MANTRA DAO ZENTEREST platform and proceeded to use the funds as collateral to borrow a series of other cryptocurrency assets that were then stolen:
https://etherscan.io/tx/0x46526cbf…24795f
The owner of StakingReward contract sent extra tokens to the external wallet owned bt the attacker:
https://etherscan.io/tx/0xbcea5abc…31c3c7
A series of Bondly-held wallets were compromised and the funds immediately transferred to the Attacker’s wallet address. In addition, hundreds of small transfers of 10,000, 20,000, and 200,000 BONDLY were made to numerous wallet addresses, which we believe were owned by the Attacker. In addition to Bondly tokens, the transfers included 271,790,246 $BONDLY BSC tokens and 6,620,128 $BONDLY Polygon tokens.
The attacker moved 3,569 Uniswap V2 liquidity tokens from compromised Bondly wallets to the Attacker’s wallet. Later it was identified that Attacker removed liquidity from Uniswap:
https://etherscan.io/tx/0x6a8f9d1e…426d9d
501 Ether, stored at the following Ethereum address, which included Bondly assets, were sent to Tornado Cash through a series of transactions by the attacker:
https://etherscan.io/address/0xa465e908…b2f634
https://bloxy.info/txs/calls_from/0xa465e908…b2f634?signature_id=994162&smart_contract_address_bin=0x722122df…5b6967
The attacker sent 5.2m DAI and 202 ETH to the Tornado Cash mixer:
https://bloxy.info/txs/calls_from/0xc433d50d…0d25e8?signature_id=994162&smart_contract_address_bin=0x722122df…5b6967
Incident Report
Protocol Information
Market Context at Time of Hack
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.
What Auditors Should Check
If you're auditing a protocol with similar architecture to Bondly, these are the critical security checks that could have prevented this incident (July 2021).
- Verify all logic paths related to Private Key Compromised (Unknown Method) / Access Control are guarded by proper access controls and input validation - see the Access Control Attacks attack class for patterns
- 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.
Free TrialFunds Recovery
Recovered
$6.8M
Net Loss
0
Related Attack Classes
The technique used in this hack maps to these vulnerability classes in our security curriculum:
Sources & References
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01
Source 1 https://rekt.news/bondly-rekt/
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Learn to Prevent the Next Bondly
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