CVE-2018-13772 in TheFlashToken
Summary
by MITRE
The mintToken function of a smart contract implementation for TheFlashToken, 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 • 03/03/2020
The vulnerability identified as CVE-2018-13772 represents a critical integer overflow flaw within the mintToken function of TheFlashToken smart contract implementation on the Ethereum blockchain. This vulnerability resides in the contract's token minting mechanism where the owner can manipulate user balances through improper integer handling. The flaw allows an attacker with contract ownership privileges to set any user's token balance to an arbitrary value, effectively enabling unauthorized token distribution or manipulation of account balances.
The technical root cause of this vulnerability aligns with CWE-190, which specifically addresses integer overflow conditions. In the context of Ethereum smart contracts, this occurs when arithmetic operations exceed the maximum value that can be stored in the designated data type, causing the value to wrap around to zero or negative numbers. The mintToken function likely performs unchecked arithmetic operations on token amounts without proper overflow checks, particularly when dealing with uint256 data types that can overflow when exceeding their maximum representable value of 2^256 - 1.
The operational impact of this vulnerability is severe and multifaceted from a cybersecurity perspective. An attacker with owner privileges can manipulate token distributions to create unlimited tokens, potentially leading to massive dilution of token value or complete loss of funds for other users. This vulnerability directly violates the fundamental principles of blockchain security and asset integrity, as it allows for unauthorized minting of tokens without proper authorization mechanisms. The impact extends beyond simple financial loss, as it undermines trust in the token ecosystem and can compromise the entire smart contract's integrity.
From an adversarial perspective, this vulnerability maps to multiple ATT&CK techniques including TA0001 (Initial Access) through privilege escalation and TA0002 (Execution) via smart contract manipulation. The vulnerability enables attackers to execute arbitrary balance modifications without detection, making it particularly dangerous for token holders and investors. The flaw's exploitation requires only the owner's private key access, making it a critical issue for any token contract that does not implement proper access controls or input validation mechanisms.
Mitigation strategies for CVE-2018-13772 should include immediate implementation of proper integer overflow checks using require statements with bounds validation, adoption of safe math libraries such as OpenZeppelin's SafeMath, and comprehensive code audits for all smart contract functions that handle arithmetic operations. Additionally, implementing proper access control mechanisms and regular security testing can prevent similar vulnerabilities from occurring in future deployments. The remediation process must also include thorough testing of all arithmetic operations and balance modifications to ensure that integer overflows cannot occur under any circumstances, aligning with industry best practices for smart contract security and following the principle of least privilege for contract owners.