- Reported
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- Issued
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- Package
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cggmp24
(crates.io)
- Type
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Vulnerability
- Categories
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- Keywords
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#hd-wallet
#presignature
#tss
- Aliases
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- References
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- Patched
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Description
This attack is against presignatures used in very specific context:
- Presignatures + HD wallets derivation: security level reduces to 85 bits
Previously you could generate a presignature, and then choose a HD derivation path while issuing a partial signature via Presignature::set_derivation_path, which is malleable to attack that reduces target security level. To mitigate, this method has been removed from API.
- Presignatures + "raw signing" (when signer signs a hash without knowing an original message): results into signature forgery attack
Previously, you could use Presignature::issue_partial_signature with hashed message without ever providing original mesage. In new API, this method only accepts digests for which original message has been observed.
Patches
cggmp24 v0.7.0-alpha.2 release contains API changes that make it impossible to use presignatures in contexts in which it reduces security. Follow the migration guidelines to upgrade.
Workarounds
You can continue using un-patched versions of library as long as you don't use presignatures in said scenarios where it weakens system security. To be sure, migrate to patched version that excludes presignatures from being used in such scenarios.
References
Read our blog post to learn more.
Advisory available under CC0-1.0
license.