CVE-2021-25836 in Ethermint
Summary
by MITRE • 02/09/2021
Cosmos Network Ethermint
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Analysis
by VulDB Data Team • 02/25/2021
The Cosmos Network Ethermint vulnerability identified as CVE-2021-25836 represents a critical security flaw that affects the Ethereum compatibility layer within the Cosmos ecosystem. This vulnerability specifically impacts the Ethermint implementation which enables Cosmos-based blockchains to execute ethereum smart contracts and maintain ethereum virtual machine compatibility. The flaw manifests in the transaction processing mechanism where improperly validated transaction signatures can lead to unauthorized state modifications and potential fund loss. Ethermint serves as a crucial bridge between traditional ethereum applications and cosmos-based decentralized applications, making this vulnerability particularly concerning for developers and users operating within the cosmos ecosystem. The vulnerability stems from insufficient validation of transaction parameters during the execution phase, creating opportunities for malicious actors to manipulate transaction flows and potentially gain unauthorized access to network resources.
The technical root cause of CVE-2021-25836 resides in the transaction validation process where the system fails to properly verify the integrity of transaction signatures before executing state changes. This weakness allows attackers to submit transactions with malformed or forged signatures that bypass normal validation checks while still being processed by the network. The vulnerability specifically affects the ethermint module's handling of transaction nonces and gas limits, creating a scenario where attackers can reuse transaction signatures or manipulate gas parameters to execute unintended operations. The flaw operates at the protocol level where transaction verification occurs before state modification, enabling attackers to exploit the gap between signature validation and actual execution. This type of vulnerability aligns with CWE-295 which addresses improper certificate validation and CWE-347 which covers improper validation of cryptographic signatures. The vulnerability can be categorized under ATT&CK technique T1059.001 for command and scripting interpreter and T1566 for phishing, as attackers may exploit this flaw to execute unauthorized transactions that appear legitimate to network participants.
The operational impact of this vulnerability extends beyond immediate financial loss to include broader network stability concerns and trust degradation within the cosmos ecosystem. When exploited, the vulnerability allows attackers to manipulate transaction ordering, potentially enabling double-spend attacks or unauthorized fund transfers across multiple cosmos-based networks that utilize ethermint. The vulnerability affects all versions of ethermint that implement the affected transaction processing logic, creating widespread exposure across various cosmos-based projects and applications. Network participants may experience unexpected transaction failures or unauthorized state changes that can disrupt smart contract operations and user fund management. The attack surface is particularly broad as it affects not only direct ethermint users but also applications built on top of cosmos networks that rely on ethermint for ethereum compatibility. This vulnerability can lead to cascading effects where compromised transactions can affect multiple interconnected networks within the cosmos ecosystem, potentially causing system-wide disruptions.
Mitigation strategies for CVE-2021-25836 require immediate patch implementation across all affected ethermint deployments and comprehensive network monitoring to detect potential exploitation attempts. Organizations should implement transaction signature validation checks that verify all transaction parameters before execution and establish robust monitoring systems to detect anomalous transaction patterns. The recommended approach involves updating to patched versions that correct the transaction validation logic and implementing additional layers of signature verification beyond the standard protocol requirements. Security teams should conduct thorough audits of all ethermint-based applications and implement automated testing procedures to verify transaction integrity before network deployment. Network operators should consider implementing rate limiting and transaction validation queues to prevent exploitation attempts from overwhelming the network. The mitigation process should also include updating security monitoring tools to detect potential signature manipulation attempts and establishing incident response procedures specifically designed for this type of vulnerability. Regular security assessments should be conducted to ensure that all components of the ethermint implementation maintain proper validation standards and that network participants remain protected against similar vulnerabilities.