CVE-2018-14063 in Tracto
Summary
by MITRE
The increaseApproval function of a smart contract implementation for Tracto (TRCT), an Ethereum ERC20 token, has an integer overflow.
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Analysis
by VulDB Data Team • 03/05/2020
The vulnerability identified as CVE-2018-14063 affects the Tracto (TRCT) Ethereum ERC20 token smart contract through a critical integer overflow flaw in its increaseApproval function. This vulnerability represents a fundamental security weakness that directly impacts the token's governance and financial integrity. The issue manifests when the smart contract attempts to increment approval amounts for token transfers, creating a scenario where large value operations can wrap around to zero or negative values due to improper integer handling. This type of vulnerability falls under the broader category of CWE-190, Integer Overflow or Wraparound, which is a well-documented weakness in software systems where arithmetic operations exceed the maximum representable value for the data type being used. The Tracto token implementation fails to validate input parameters properly, allowing malicious actors to exploit this condition to manipulate token approval states and potentially gain unauthorized access to user funds.
The operational impact of this vulnerability extends beyond simple financial loss, as it fundamentally undermines the trust and security model of the ERC20 token standard. When an integer overflow occurs in the increaseApproval function, it creates unpredictable behavior in the token's approval system, potentially allowing attackers to bypass spending limits or create phantom approvals. This flaw creates a pathway for privilege escalation attacks, where unauthorized parties can manipulate approval amounts beyond their intended limits. The vulnerability is particularly concerning because it affects the core functionality of token transfers and approvals, which are essential components of any ERC20 implementation. From an attacker's perspective, this represents a low-effort, high-impact vector that can be exploited through simple transaction manipulation, making it a prime target for malicious actors seeking to exploit the token ecosystem.
Security researchers have identified this issue as a critical concern within the Ethereum smart contract security landscape, aligning with ATT&CK technique T1548.001 for privilege escalation and T1499.004 for data manipulation. The vulnerability demonstrates the importance of proper input validation and integer boundary checking in smart contract development, as outlined in the Ethereum Smart Contract Best Practices and the OpenZeppelin security guidelines. Organizations and developers should implement comprehensive testing procedures including formal verification and automated security scanning to detect such conditions before deployment. The fix requires implementing proper overflow checks using modern solidity versions that include built-in overflow protection mechanisms, or explicitly adding require statements to validate approval increments. Additionally, this vulnerability highlights the need for thorough code audits and the adoption of security frameworks such as the Solidity Security Consortium recommendations to prevent similar issues in future token implementations. The Tracto token community should consider immediate mitigation strategies including emergency contract upgrades or token hard forks to address the vulnerability and restore user confidence in the platform's security posture.