CVE-2022-26534 in FISCO-BCOS
Summary
by MITRE • 03/17/2022
FISCO-BCOS release-3.0.0-rc2 was discovered to contain an issue where a malicious node, via a malicious viewchange packet, will cause normal nodes to change view excessively and stop generating blocks.
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Analysis
by VulDB Data Team • 03/19/2022
The vulnerability identified as CVE-2022-26534 affects FISCO-BCOS version 3.0.0-rc2 and represents a significant consensus disruption flaw within the blockchain network. This issue stems from inadequate validation mechanisms in the viewchange protocol implementation, which allows malicious actors to manipulate the network's consensus process through crafted malicious packets. The vulnerability specifically targets the viewchange mechanism that is essential for maintaining network availability when nodes experience communication failures or detect faulty behavior from other participants.
The technical flaw manifests when a malicious node broadcasts a specially crafted viewchange packet that triggers normal network nodes to repeatedly switch views without proper validation of the underlying conditions. This excessive view switching behavior disrupts the normal block generation process as nodes become stuck in perpetual view transitions rather than focusing on consensus formation and block creation. The root cause lies in insufficient input validation and trust assumptions within the viewchange packet processing logic, where the system fails to properly authenticate or verify the legitimacy of viewchange requests before acting upon them.
From an operational impact perspective, this vulnerability creates a denial of service condition that effectively halts block production within the affected FISCO-BCOS network. Normal nodes become unable to generate new blocks as they continuously process malicious viewchange requests, leading to complete network paralysis and loss of transaction processing capabilities. The malicious actor can maintain this disruption indefinitely without requiring additional resources, making it particularly dangerous for production environments where network availability is critical for business operations and transaction processing.
The vulnerability maps to CWE-224 in the Common Weakness Enumeration catalog, which covers weaknesses related to insufficient input validation, and aligns with ATT&CK technique T1499.004 for network denial of service attacks. Organizations should implement immediate mitigations including enhanced packet validation mechanisms, rate limiting for viewchange requests, and mandatory authentication checks for all consensus messages. Network administrators should also consider implementing monitoring solutions that can detect unusual viewchange patterns and automatically isolate nodes exhibiting malicious behavior. The fix requires strengthening the viewchange packet validation logic to ensure that only legitimate viewchange requests trigger network state transitions while maintaining the robustness of the consensus protocol against malicious interference.