Network disruption via signed shift-amount coercion
Published Dec 13, 2021 · Updated Aug 4, 2024
Integer coercion in Hyperledger Besu 21.10.0 through 21.10.1 allows remote attackers to interrupt block validation via crafted shifts. The EVM SHL, SHR, and SAR handlers convert a 256-bit shift amount to a signed 32-bit integer but fail to reject negative results before passing them to shift methods. No authentication or user interaction is required; a shift of roughly 2 billion to 4 billion bits can stop validators, exclude transactions, or split mixed-client networks.
Summary
What happened
Integer coercion in Hyperledger Besu 21.10.0 through 21.10.1 allows remote attackers to interrupt block validation via crafted shifts. The EVM SHL, SHR, and SAR handlers convert a 256-bit shift amount to a signed 32-bit integer but fail to reject negative results before passing them to shift methods. No authentication or user interaction is required; a shift of roughly 2 billion to 4 billion bits can stop validators, exclude transactions, or split mixed-client networks.
The record
- CVE
- CVE-2021-41272
- Published
- Dec 13, 2021
- Updated
- Aug 4, 2024
- Vendor
- Hyperledger Foundation
- Product
- Hyperledger Besu
- Classifications
- CWE-681, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 13, 2021CVE publishedPublication date reported by the CVE source.
- Aug 4, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=> 21.7.4, < 21.10.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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