CVE-2021-34272 in RobotCoin
Summary
by MITRE • 08/04/2021
A security flaw in the 'owned' function of a smart contract implementation for RobotCoin (RBTC), a tradeable Ethereum ERC20 token, allows attackers to hijack victim accounts and arbitrarily increase the digital supply of assets.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 08/07/2021
The vulnerability identified as CVE-2021-34272 represents a critical flaw in the RobotCoin (RBTC) smart contract implementation that directly impacts the integrity and security of the Ethereum-based ERC20 token ecosystem. This vulnerability specifically resides within the 'owned' function of the smart contract, which is designed to manage ownership and control permissions within the token system. The flaw enables unauthorized actors to exploit the contract's access control mechanisms and gain illicit control over victim accounts, fundamentally compromising the security model that underpins the token's operations.
The technical nature of this vulnerability stems from improper access control implementation within the smart contract's ownership functions. When attackers exploit this flaw, they can manipulate the 'owned' function to assume control over existing user accounts without proper authorization. This unauthorized account takeover capability allows malicious actors to perform actions that should only be executable by legitimate owners, including transferring tokens, modifying account balances, and potentially executing additional malicious operations within the contract's scope. The vulnerability essentially creates a backdoor mechanism that bypasses the intended authentication and authorization protocols.
The operational impact of this vulnerability extends beyond simple account takeover to include the critical issue of arbitrary supply inflation. Attackers who successfully hijack accounts can exploit the compromised access to increase the digital supply of RobotCoin assets beyond the intended limits. This supply manipulation directly affects the token's economic model and value proposition, potentially leading to significant financial losses for legitimate token holders. The combination of account takeover and supply inflation creates a multi-faceted threat that undermines both the security and economic stability of the RobotCoin ecosystem.
This vulnerability aligns with CWE-284, which addresses improper access control in software systems, and demonstrates how smart contract implementations can fail to properly enforce access control mechanisms. From an ATT&CK framework perspective, this flaw maps to privilege escalation techniques where attackers move from limited access to full administrative control over the contract's resources. The attack vector specifically relates to the contract's function execution flow and demonstrates how inadequate input validation and access control checks can create persistent security weaknesses in decentralized applications. Organizations should implement comprehensive code review processes, formal verification techniques, and regular security audits to prevent similar vulnerabilities in smart contract implementations.
Mitigation strategies for this vulnerability require immediate contract upgrades that properly implement access control checks and validate ownership permissions before executing sensitive operations. The fix should include robust input validation, proper access control mechanisms, and comprehensive logging of ownership-related transactions. Additionally, implementing multi-signature requirements for critical operations and establishing proper account recovery procedures can help reduce the impact of such vulnerabilities. Regular security assessments and penetration testing of smart contracts should become standard practice for all token implementations to identify and remediate similar access control weaknesses before they can be exploited by malicious actors in the decentralized finance ecosystem.