CVE-2018-17111
📋 TL;DR
This CVE describes an access control vulnerability in the Coinlancer smart contract's onlyOwner modifier. The incorrect comparison allows any user to call functions restricted to the contract owner, potentially enabling unauthorized token transfers or contract modifications. All users of the vulnerable Coinlancer token contract are affected.
💻 Affected Systems
- Coinlancer (CL) ERC20 token smart contract
📦 What is this software?
Coinlancer by Coinlancer
⚠️ Risk & Real-World Impact
Worst Case
Malicious actor gains full control of the smart contract, allowing them to drain all tokens, modify contract logic, or lock legitimate users out permanently.
Likely Case
Unauthorized users exploit the vulnerability to transfer tokens from the contract or modify parameters that should be owner-restricted.
If Mitigated
Proper access controls prevent unauthorized calls, limiting functions to the legitimate contract owner only.
🎯 Exploit Status
The vulnerability is simple to exploit once identified - any Ethereum address can call the affected functions.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Updated smart contract implementation
Vendor Advisory: https://github.com/TEAM-C4B/CVE-LIST/tree/master/CVE-2018-17111
Restart Required: No
Instructions:
1. Deploy a new, corrected smart contract with proper onlyOwner modifier implementation. 2. Migrate token holders to the new contract. 3. Deprecate the vulnerable contract.
🔧 Temporary Workarounds
Contract monitoring and emergency pause
allMonitor contract for unauthorized transactions and implement emergency pause functionality if available
Not applicable - requires smart contract interaction
🧯 If You Can't Patch
- Monitor all contract transactions for unauthorized owner function calls
- Consider migrating to a new, secure contract implementation if possible
🔍 How to Verify
Check if Vulnerable:
Review smart contract source code for the onlyOwner modifier implementation and verify msg.sender == owner comparisonCheck Version:
Check contract address and verify against known vulnerable implementationsVerify Fix Applied:
Audit the new contract code to confirm proper access control implementation📡 Detection & Monitoring
Log Indicators:
- Unauthorized calls to owner-restricted functions in blockchain transaction logs
Network Indicators:
- Suspicious transactions to the vulnerable contract address
SIEM Query:
Not applicable - requires blockchain monitoring tools