CVE-2018-13734 in AZTToken
Summary
by MITRE
The mintToken function of a smart contract implementation for AZTToken, 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 • 02/28/2020
The CVE-2018-13734 vulnerability represents a critical integer overflow flaw in the mintToken function of AZTToken smart contract implementations running on the Ethereum blockchain. This vulnerability stems from improper input validation and arithmetic operations within the token contract's code, creating a pathway for malicious actors to manipulate token balances. The flaw specifically affects the contract owner who can exploit this vulnerability to arbitrarily set any user's token balance to any desired value, fundamentally compromising the integrity of the token economy.
The technical nature of this vulnerability aligns with CWE-190, which categorizes integer overflow conditions that can lead to unexpected behavior in software systems. In the context of smart contracts, this flaw manifests when the mintToken function performs arithmetic operations without proper bounds checking or overflow detection mechanisms. The contract owner can leverage this weakness to manipulate the total supply or individual user balances by carefully crafting inputs that cause the underlying integer arithmetic to wrap around, resulting in unintended values. This type of vulnerability is particularly dangerous in decentralized applications because it operates at the protocol level and can affect all users within the token ecosystem.
The operational impact of CVE-2018-13734 extends beyond simple balance manipulation, creating cascading effects throughout the token's functionality and user trust. An attacker with access to the contract owner privileges can potentially drain liquidity from token holders, manipulate market dynamics, or create artificial scarcity by setting balances to extreme values. The vulnerability also introduces risks to any systems or protocols that depend on accurate token balances, as the integrity of the entire token economy becomes compromised. This flaw can be exploited through various attack vectors including direct contract calls, transaction manipulation, or by leveraging other related vulnerabilities within the same contract ecosystem.
Mitigation strategies for this vulnerability require immediate code review and patching of the affected smart contract implementations. The recommended approach involves implementing proper integer overflow protection mechanisms such as using safe math libraries, adding comprehensive input validation, and ensuring all arithmetic operations include overflow checks. Organizations should also consider implementing access control measures that limit the privileges of contract owners and establish multi-signature requirements for critical operations. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and resource hijacking, emphasizing the need for robust contract security auditing and continuous monitoring of token contract behavior. Regular security assessments and formal verification of smart contract code should become standard practice to prevent similar vulnerabilities from being introduced in future implementations.