Incident Overview
Stars Arena, an Avalanche-based project, was exploited through a reentrancy attack, leading to a loss of 2,974,530 USD worth 266,102 AVAX.
Stars Arena is a social platform on the Avalanche chain. On October 7, 2023, the platform suffered a reentrancy attack. The attacker drained funds from the Stars Arena contract, amounting to 2,974,530 USD (266,102 AVAX).
The Attacker created a contract that distributed the stolen funds to many addresses, sending 1,000 AVAX each. During the call of the 0xe9ccf3a3 function, the attacker reentered and called the 0x5632b2e4 function, setting a block height. This height was then used as a parameter in the sellShares function, resulting in an abnormally large calculated amount of AVAX to send.
Attacker Address:
https://cchain.explorer.avax.network/address/0xa2ebf3fc…b4ad7a
Malicious Transaction:
https://cchain.explorer.avax.network/tx/0x4f37ffec…e17ac5
Malicious Contract:
https://cchain.explorer.avax.network/address/0x7f283edc…d2c7ac
Funds Distribution Transactions:
https://snowtrace.io/tx/0x8f5b2e88…ef9fb1
Some of the Stolen Funds Holders:
https://cchain.explorer.avax.network/address/0x9b5ec83e…2d418d
https://cchain.explorer.avax.network/address/0xded436c2…c56b3e
Incident Report
Protocol Information
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 Stars Arena, these are the critical security checks that could have prevented this incident (October 2023).
- Verify all logic paths related to Reentrancy are guarded by proper access controls and input validation - see the Reentrancy attack class for patterns
- Check that all state-changing functions follow the Checks-Effects-Interactions (CEI) pattern to prevent reentrancy and logic ordering bugs
- 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
$2.7M
Net Loss
297453
Post-Incident Timeline
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2023-10-11
Was reached an agreement with the individual responsible for the recent security breach. The attacker returned 90% of the stolen funds
Related Attack Classes
The technique used in this hack maps to these vulnerability classes in our security curriculum:
Sources & References
- 01
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02
Web Archive https://archive.ph/27uKl
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