CVE-2018-13184 in TravelZedi Token
Summary
by MITRE
The mintToken function of a smart contract implementation for TravelZedi Token (ZEDI), 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 • 02/25/2020
The TravelZedi Token smart contract implementation contains a critical integer overflow vulnerability in its mintToken function that fundamentally compromises the token's integrity and security model. This vulnerability exists within the Ethereum blockchain ecosystem where smart contracts execute with absolute certainty once deployed, making such flaws particularly dangerous as they cannot be easily patched after deployment. The mintToken function, designed to create new tokens and distribute them to users, suffers from an unchecked arithmetic operation that allows the contract owner to manipulate token balances beyond normal constraints.
The technical flaw manifests as an integer overflow condition where the mintToken function fails to validate or constrain the token amount being minted, enabling the contract owner to specify values that exceed the maximum representable value for the underlying data type. This overflow occurs during the balance update process, allowing the owner to set any user's balance to an arbitrary value, potentially including extremely large numbers or even negative values that wrap around due to the overflow behavior. The vulnerability directly maps to CWE-190, Integer Overflow or Wraparound, which is classified as a critical weakness in software systems that can lead to unpredictable behavior and security breaches.
The operational impact of this vulnerability is severe and multifaceted, affecting both the economic integrity of the token and the broader ecosystem. An attacker with contract ownership privileges can manipulate token distributions to create unlimited supply, inflate their own holdings, or manipulate other users' balances to gain unfair advantages. This capability undermines the fundamental trust in the token's supply mechanism and can lead to market manipulation, loss of user funds, and complete compromise of the token's economic model. The vulnerability also enables potential denial-of-service scenarios where malicious actors could set user balances to zero or extremely high values, disrupting normal token operations and potentially causing system-wide failures.
From a cybersecurity perspective, this vulnerability aligns with ATT&CK technique T1059.006 for smart contract exploitation and demonstrates how privilege escalation within blockchain environments can result in complete system compromise. The vulnerability's exploitation requires only the private key associated with the contract owner account, making it particularly dangerous as it leverages the trusted owner role to perform unauthorized actions. Organizations should implement comprehensive smart contract auditing processes that include integer overflow checks, proper input validation, and access control mechanisms to prevent such vulnerabilities. The remediation involves implementing proper bounds checking, using safe arithmetic libraries, and ensuring that all balance updates are validated against maximum allowable values. Additionally, the contract should employ proper ownership transfer mechanisms and consider using multi-signature wallets for owner accounts to reduce the risk of single points of failure. The incident highlights the critical importance of thorough security testing and formal verification of smart contracts before deployment, as these vulnerabilities can have lasting consequences that affect the entire token ecosystem and user trust.