CVE-2021-33403
📋 TL;DR
An integer overflow vulnerability in the transfer function of the Lancer Token (LNCToken) smart contract allows the contract owner to manipulate token transfers between large accounts, potentially causing unexpected financial losses. This affects users holding or transacting with this specific ERC20 token on the Ethereum blockchain.
💻 Affected Systems
- Lancer Token (LNCToken) smart contract
📦 What is this software?
Blocklancertoken by Blocklancertoken Project
⚠️ Risk & Real-World Impact
Worst Case
Contract owner could drain tokens from large accounts or manipulate token balances, causing significant financial losses to token holders.
Likely Case
Contract owner exploits the vulnerability to siphon tokens from large holders during transfers, resulting in direct financial theft.
If Mitigated
No impact if users avoid interacting with the vulnerable contract or if the owner doesn't exploit it.
🎯 Exploit Status
Exploitation requires contract owner privileges; public analysis available in GitHub repository
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not applicable
Vendor Advisory: Not available
Restart Required: No
Instructions:
Deploy new smart contract with fixed transfer function and migrate token holders to new contract
🔧 Temporary Workarounds
Avoid vulnerable contract
allDo not hold or transact with the vulnerable LNCToken contract
Token migration
allMigrate to a new, audited token contract if available
🧯 If You Can't Patch
- Monitor transactions involving the vulnerable contract address for suspicious activity
- Implement wallet-level controls to prevent interactions with the vulnerable contract
🔍 How to Verify
Check if Vulnerable:
Check if interacting with contract address 0x63e634330a20150dbb61b15648bc73855d6ccf07Check Version:
Not applicable for smart contractsVerify Fix Applied:
Verify new contract address has been deployed and token migration completed📡 Detection & Monitoring
Log Indicators:
- Unusual token transfers from large accounts
- Contract owner initiating unexpected transfers
Network Indicators:
- Transactions to/from vulnerable contract address
SIEM Query:
Not applicable for blockchain transactions🔗 References
- https://cn.etherscan.com/address/0x63e634330a20150dbb61b15648bc73855d6ccf07#code
- https://github.com/MRdoulestar/SC-RCVD/blob/main/Vulnerabilities/LNCToken.md
- https://cn.etherscan.com/address/0x63e634330a20150dbb61b15648bc73855d6ccf07#code
- https://github.com/MRdoulestar/SC-RCVD/blob/main/Vulnerabilities/LNCToken.md
