CVE-2018-13509 in IamRich
Summary
by MITRE
The mintToken function of a smart contract implementation for IamRich, 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-2018-13509 represents a critical integer overflow flaw within the mintToken function of the IamRich Ethereum token smart contract implementation. This vulnerability resides in the core token functionality that enables the contract owner to create new tokens and distribute them to users. The integer overflow occurs when the mintToken function processes token minting operations without proper bounds checking, allowing the owner to manipulate the token supply mechanism in ways that were not intended by the contract design. The flaw specifically affects the balance calculation logic where arithmetic operations can exceed the maximum value that can be stored in the underlying data type, causing the value to wrap around to an unexpected lower value.
The technical exploitation of this vulnerability stems from the lack of input validation and overflow protection within the smart contract's mintToken function. When the contract owner invokes this function, they can manipulate the token balance of any user account by specifying values that trigger the integer overflow condition. This creates a scenario where the owner can set a user's balance to any arbitrary value, potentially including extremely large numbers that could disrupt the token economy or enable unauthorized minting of unlimited tokens. The vulnerability is particularly dangerous because it directly impacts the fundamental property of token scarcity and ownership that underpins blockchain-based assets, allowing the contract owner to bypass normal token distribution mechanisms and directly control user balances.
The operational impact of this vulnerability extends beyond simple balance manipulation to encompass potential financial loss and contract integrity compromise. An attacker with owner privileges could inflate user balances to malicious values, potentially causing the token contract to behave unpredictably or even become unusable. The vulnerability also creates a pathway for unauthorized token creation that could destabilize the entire token economy, as the attacker could generate tokens without proper authorization or oversight. This flaw essentially grants the contract owner unprecedented control over the token distribution mechanism, undermining the trust and security assumptions that users rely upon when interacting with the smart contract. The implications are particularly severe in decentralized finance applications where token balances directly affect collateral values and loan calculations.
Mitigation strategies for this vulnerability require immediate implementation of proper integer overflow protection mechanisms within the smart contract code. The most effective approach involves adding comprehensive input validation and bounds checking to all arithmetic operations, particularly within functions that manipulate token balances or supply. The contract should implement safe math libraries or use compiler features that automatically detect and prevent overflow conditions, as recommended by the CWE-190 standard for integer overflow vulnerabilities. Additionally, the contract owner should implement proper access controls and audit mechanisms to prevent unauthorized use of privileged functions. The ATT&CK framework's privilege escalation techniques are relevant here, as this vulnerability enables an attacker to gain unauthorized control over token distribution mechanisms and user balances. Regular security audits and formal verification of smart contract code should become standard practice to prevent similar vulnerabilities from being introduced in future implementations. The fix must ensure that all balance updates are validated against reasonable limits and that arithmetic operations properly handle edge cases to prevent wraparound behavior that could be exploited for malicious purposes.