CVE-2018-13556 in COSMOTokenERC20
Summary
by MITRE
The mintToken function of a smart contract implementation for COSMOTokenERC20, an Ethereum token, has an integer overflow that allows the owner of the contract to set the balance of an arbitrary user to any value.
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Analysis
by VulDB Data Team • 02/27/2020
The vulnerability identified as CVE-2018-13556 represents a critical integer overflow flaw within the mintToken function of the COSMOTokenERC20 smart contract implementation on the Ethereum blockchain. This vulnerability stems from inadequate input validation and arithmetic overflow handling within the contract's token minting mechanism, creating a fundamental security weakness that directly impacts the contract's integrity and user fund safety. The flaw allows the contract owner to manipulate token balances of arbitrary users, effectively enabling unauthorized fund manipulation and potential financial loss for token holders. The vulnerability manifests when the mintToken function processes token minting operations without proper bounds checking, permitting integer overflow conditions that can be exploited to manipulate account balances beyond normal operational limits.
The technical implementation of this vulnerability aligns with CWE-190, Integer Overflow or Wraparound, which specifically addresses situations where arithmetic operations produce results that exceed the maximum value representable by the data type. In Ethereum smart contracts, this typically occurs when unsigned integer values exceed their maximum bounds, causing the values to wrap around to zero or negative numbers. The COSMOTokenERC20 contract fails to implement proper overflow checks during the mintToken function execution, allowing an attacker with owner privileges to exploit this weakness by manipulating the minting parameters to achieve unintended balance modifications. The vulnerability is particularly dangerous because it operates at the core token management level, where the contract owner's privileges are leveraged to manipulate user balances without detection.
The operational impact of this vulnerability extends beyond simple financial manipulation to encompass broader security implications for the entire token ecosystem. An attacker with owner access can effectively create unlimited tokens for themselves or other users, potentially leading to massive dilution of token value and complete loss of user funds. The vulnerability undermines the fundamental trust model of ERC20 token implementations, where users expect their balances to be accurately maintained and protected from unauthorized modifications. This flaw can result in severe financial losses for token holders, contract devaluation, and potential complete loss of the token's utility within the Ethereum ecosystem. The vulnerability's exploitation capability is amplified because it requires only the owner's private key access, making it particularly dangerous for contracts where owner privileges are not properly secured or monitored.
Mitigation strategies for CVE-2018-13556 should focus on implementing comprehensive input validation and arithmetic overflow protection mechanisms within the smart contract code. The most effective remediation involves adding explicit overflow checks using modern Solidity features such as safeMath libraries or explicit overflow detection mechanisms before any arithmetic operations. Contract owners should also implement proper access control measures and consider using multi-signature wallets for owner privileges to reduce the risk of unauthorized access. Additionally, regular security audits and formal verification of smart contract code should be conducted to identify similar vulnerabilities before they can be exploited. The implementation of these security measures aligns with ATT&CK technique T1059.006 for smart contract security, which emphasizes the importance of preventing code injection and manipulation vulnerabilities that can be exploited to gain unauthorized control over contract functionality and user assets.