CVE-2018-13565 in Co2Bit
Summary
by MITRE
The mintToken function of a smart contract implementation for Co2Bit, 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-2018-13565 represents a critical integer overflow flaw within the mintToken function of the Co2Bit Ethereum token smart contract implementation. This vulnerability stems from improper input validation and arithmetic handling within the contract's codebase, creating a pathway for unauthorized manipulation of token balances. The flaw specifically affects the contract's ability to properly manage and validate numeric values during token minting operations, allowing malicious actors to exploit the overflow condition for unintended consequences.
The technical exploitation of this vulnerability occurs through the manipulation of integer values in the mintToken function where the contract fails to properly validate or constrain the parameters passed to the function. When an attacker provides carefully crafted input values, the integer overflow allows them to bypass normal balance limitations and directly set any user's token balance to an arbitrary value. This flaw aligns with CWE-190, which specifically addresses integer overflow and underflow conditions in software implementations. The vulnerability exists at the core of the contract's mathematical operations where the system does not properly check for overflow conditions during arithmetic calculations involving token amounts.
The operational impact of this vulnerability is severe and far-reaching for the Co2Bit token ecosystem. An attacker with access to the contract owner privileges can manipulate the token distribution mechanism to create unlimited tokens or manipulate existing balances to their advantage. This creates potential for financial loss for legitimate token holders and undermines the fundamental integrity of the token economy. The vulnerability enables scenarios where an attacker could set another user's balance to an extremely high value, potentially causing the contract to behave unpredictably or allowing for unauthorized token transfers. This type of flaw directly impacts the security model of the Ethereum-based token and compromises the trust assumptions that users place in the smart contract system.
The vulnerability demonstrates a classic example of how improper input validation and lack of overflow checking in smart contracts can create critical security holes. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and resource manipulation within blockchain environments. The attack surface is particularly concerning because it allows for direct manipulation of token balances without requiring complex multi-step attacks. Mitigation strategies should focus on implementing proper integer overflow protections, including explicit bounds checking, using safe arithmetic libraries, and conducting comprehensive code reviews for all mathematical operations within smart contracts. Additionally, the contract should implement proper access controls and validation mechanisms to prevent unauthorized manipulation of user balances, ensuring that all token operations maintain the integrity of the underlying blockchain state.