CVE-2018-13684 in ZIP
Summary
by MITRE
The mintToken function of a smart contract implementation for ZIP, 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 vulnerability identified in CVE-2018-13684 represents a critical integer overflow flaw within the mintToken function of a smart contract implementation for the ZIP Ethereum token. This vulnerability stems from inadequate input validation and arithmetic overflow handling within the contract's codebase, creating a fundamental weakness that directly impacts the token's core functionality and security model. The flaw allows the contract owner to manipulate user balances arbitrarily, effectively undermining the decentralized and trustless principles that govern blockchain-based token systems. The integer overflow occurs when the mintToken function processes token creation requests without proper bounds checking, enabling malicious actors with owner privileges to manipulate the underlying numeric values beyond their intended limits.
The technical exploitation of this vulnerability leverages the inherent properties of integer arithmetic in smart contract environments where values are typically stored in fixed-width data types. When the mintToken function attempts to increment user balances or perform other arithmetic operations, the lack of overflow protection causes the numeric values to wrap around to unexpected states. This behavior creates a scenario where legitimate balance calculations can be overridden by carefully crafted inputs that trigger the overflow condition. The vulnerability specifically maps to CWE-191, which describes integer underflow/overflow issues, and represents a classic example of how insufficient validation can lead to privilege escalation within blockchain smart contracts. The ATT&CK framework categorizes this as a privilege escalation technique through software exploitation, where the contract owner leverages a coding flaw to gain unauthorized control over user assets.
The operational impact of this vulnerability extends far beyond simple balance manipulation, creating a comprehensive security breach that can result in substantial financial losses for token holders. An attacker with owner access can potentially drain user accounts, create unlimited tokens, or manipulate the total supply to gain unfair advantages. The vulnerability's exploitation does not require external factors or complex attack chains, making it particularly dangerous as it can be executed immediately upon discovery by malicious actors. The affected ZIP token ecosystem would experience immediate instability, with potential loss of trust among users who rely on the contract's integrity for their holdings. The financial implications include direct asset theft, market manipulation through artificial supply control, and long-term damage to the project's reputation and user confidence in the platform's security measures.
Mitigation strategies for CVE-2018-13684 require immediate implementation of comprehensive code auditing and security review processes. The most effective remediation involves adding proper integer overflow protection through explicit bounds checking and using safe arithmetic libraries such as OpenZeppelin's SafeMath implementation. Contract owners must implement comprehensive input validation routines that verify all numeric inputs against expected ranges and implement proper error handling mechanisms that prevent overflow conditions from occurring. The solution should also include regular security audits and formal verification processes to identify similar vulnerabilities across the entire smart contract codebase. Additionally, implementing time-based access controls and multi-signature requirements for privileged functions can reduce the risk of unauthorized exploitation, while maintaining transparency through comprehensive logging of all mintToken function calls to detect potential malicious activity. The fix should align with industry best practices established by the Ethereum Smart Contract Security Standard and should be validated through independent security assessments before deployment to production environments.