Signature forgery via unchecked zero-valued signature components
Published Nov 9, 2021 · Updated Aug 4, 2024
Improper signature verification in Stark Bank ecdsa-dotnet before 1.3.2 allows attackers to forge signatures for arbitrary messages. Zero-valued r and s components make the inverse and elliptic-curve operations collapse to zero, so verify accepts a final comparison of zero to zero for any message and public key. Any application that trusts this verifier can accept attacker-chosen data as authentically signed without prior authentication.
Summary
What happened
Improper signature verification in Stark Bank ecdsa-dotnet before 1.3.2 allows attackers to forge signatures for arbitrary messages. Zero-valued r and s components make the inverse and elliptic-curve operations collapse to zero, so verify accepts a final comparison of zero to zero for any message and public key. Any application that trusts this verifier can accept attacker-chosen data as authentically signed without prior authentication.
The record
- CVE
- CVE-2021-43569
- Published
- Nov 9, 2021
- Updated
- Aug 4, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-347
- Attack vector
- Unavailable
- Privileges
- unauthenticated
Timeline
How it unfolded
- Nov 9, 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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What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
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
- NCC Group zero-signature forgery exampleproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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