This module examined the security implications of converging Ethereum’s EVM with the Cosmos SDK via dual‑stack architectures like EVMOS/Ethermint. We explored how message routing, gas‑refund mechanics, and decorator chains work—and how gaps in these systems enabled real exploits such as Cronos fee theft and bypassing Ethermint ante handlers. By understanding these vulnerabilities and the mitigation strategies (e.g., RejectMessagesDecorator, enhanced Authz checks), developers can better secure hybrid chains. As projects like evmos pivot to full EVM alignment, it’s vital to balance interoperability with robust, simplified security designs.
Q1: How does EVMOS differentiate EVM transactions from Cosmos transactions?
A1: By inspecting each message’s type URL for an ExtensionOptionsEthereumTx flag
Q2: What is the main discrepancy between EVM and Cosmos fee markets?
A2: EVM refunds unused gas; Cosmos does not
Q3: What decorator was introduced to block unauthorized EVM messages in Cosmos transactions?
A3: RejectMessagesDecorator
Q4: How can nesting MsgEthereumTx within MsgExec lead to fee theft?
A4: It bypasses ante handlers and allows inflated gas refunds
