Private-key length disclosure via variable-time public-key derivation
Published Nov 4, 2021 · Updated Aug 4, 2024
Observable timing discrepancy in Crypto++ 8.6.0 and earlier allows attackers to infer private-key length through MakePublicKey timing. MakePublicKey derives an elliptic-curve public key in execution time positively correlated with the supplied private key's length. Exploitation requires observing invocation timing; the vendor and third parties dispute security impact because key length is user-chosen and minimally sensitive.
Summary
What happened
Observable timing discrepancy in Crypto++ 8.6.0 and earlier allows attackers to infer private-key length through MakePublicKey timing. MakePublicKey derives an elliptic-curve public key in execution time positively correlated with the supplied private key's length. Exploitation requires observing invocation timing; the vendor and third parties dispute security impact because key length is user-chosen and minimally sensitive.
The record
- CVE
- CVE-2021-43398
- Published
- Nov 4, 2021
- Updated
- Aug 4, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-203
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Nov 4, 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?
What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
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
- MakePublicKey timing correlation demonstrationproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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