Signature malleability via missing scalar bounds check
Published Aug 22, 2024 · Updated Sep 10, 2024
Signature malleability in Matrix.org Olm 3.2.16 and earlier allows attackers to create alternate valid signatures for the same message. The ed25519_verify function accepts the S half of a signature without verifying that the scalar is below the Ed25519 group order, so adding that order yields another accepted encoding. An attacker first needs a valid signature; impact is limited to applications that treat a signature's byte encoding as unique, and Matrix.org reports no known network exploitation.
Summary
What happened
Signature malleability in Matrix.org Olm 3.2.16 and earlier allows attackers to create alternate valid signatures for the same message. The ed25519_verify function accepts the S half of a signature without verifying that the scalar is below the Ed25519 group order, so adding that order yields another accepted encoding. An attacker first needs a valid signature; impact is limited to applications that treat a signature's byte encoding as unique, and Matrix.org reports no known network exploitation.
The record
- CVE
- CVE-2024-45193
- Published
- Aug 22, 2024
- Updated
- Sep 10, 2024
- Vendor
- Matrix.org
- Product
- Olm
- Classifications
- CWE-327
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 22, 2024CVE publishedPublication date reported by the CVE source.
- Sep 10, 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=0 <=3.2.16
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
- Ed25519 signature malleability demonstrationproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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