CVE-2018-13514 in esportz
Summary
by MITRE
The mintToken function of a smart contract implementation for esportz, 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 in CVE-2018-13514 represents a critical integer overflow flaw within the mintToken function of an Ethereum-based smart contract implementation for the esportz token. This vulnerability stems from improper input validation and arithmetic handling within the smart contract code, creating a pathway for unauthorized manipulation of token balances. The flaw specifically affects the contract's ability to properly manage integer values during token minting operations, allowing malicious actors to exploit the overflow condition to manipulate account balances.
The technical implementation of this vulnerability aligns with CWE-190, which describes integer overflow conditions where an integer value exceeds the maximum representable value for its data type. In the context of Ethereum smart contracts, this manifests when the mintToken function fails to validate that the addition of new tokens to a user's balance will not exceed the maximum value that can be stored in the underlying integer data type. The overflow occurs during arithmetic operations that should increment a user's token balance, but due to insufficient bounds checking, the value wraps around to an unexpected state.
The operational impact of this vulnerability is severe and directly affects the integrity of the token economy. An attacker with access to the contract owner account can manipulate any user's token balance to arbitrary values, potentially leading to unlimited token generation or the ability to set other users' balances to zero. This creates a fundamental breach in the token's economic model and undermines trust in the entire system. The vulnerability essentially allows for the creation of unlimited tokens, as the overflow condition can be exploited to bypass normal token supply limits and create tokens out of thin air.
The attack vector for this vulnerability leverages the contract owner's privileged position, making it particularly dangerous as it requires no external network access or complex exploitation techniques. The attacker simply needs to invoke the mintToken function with carefully crafted parameters that trigger the integer overflow condition. This aligns with ATT&CK technique T1059.001, where adversaries exploit vulnerabilities in application code to execute malicious actions. The vulnerability also represents a failure in the principle of least privilege, as the owner account should not be able to manipulate other users' balances without proper authorization mechanisms.
Mitigation strategies for this vulnerability require immediate implementation of proper integer overflow protection mechanisms within the smart contract code. Developers must implement comprehensive input validation, utilize safe arithmetic operations, and employ libraries or frameworks that automatically handle integer overflow protection. The contract should validate that balance additions will not exceed maximum integer values before performing operations, and consider using libraries such as OpenZeppelin's SafeMath for arithmetic operations. Additionally, implementing proper access controls and audit mechanisms can help detect unauthorized balance manipulations. The vulnerability also highlights the importance of thorough smart contract auditing and testing, particularly focusing on arithmetic operations and boundary conditions to prevent similar issues in future implementations.