GHSA-h24c-6p6p-m3vx json
tss-lib leaks secret keys in response to incorrectly constructed Paillier moduli
published 3y ago modified 3y ago
- cvss
- —
- not scored
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- —
- no score, EPSS covers CVEs only
- public exploits
- 0
- none known
Summary
### Impact
The specification of the GG18 threshold ECDSA signature protocol contains a vulnerability allowing an attacker to recover the shared secret key. If a participant generates a Paillier modulus `N` containing small factors (less than `2^100`) they can interact with other participants in the signing protocol to steal their secret key shares in as little as sixteen signing attempts. The master key can then be reconstructed from these shares.
### Patches
The implementation of GG18 in tss-lib did not prove that `N` is biprime or that it doesn't contain small factors. The fixed implementation adds the following proofs from the CGGMP21 threshold ECDSA protocol to the key generation:
- Paillier-Blum Modulus (`N` is the product of two primes) - No Small Factor (both factors of `N` are greater than `2^256`)
These proofs apply to both the Paillier encryption modulus `N`, and the modulus `NTilde` used in MTA proofs.
To address the issue in the resharing protocol, an additional round has been added to the end so that participants can confirm that they received valid proofs.
### References
- [GG18](https://eprint.iacr.org/2019/114) - [CGGMP21](https://eprint.iacr.org/2021/060)
Patch / fix
Is GHSA-h24c-6p6p-m3vx in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerAffected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| go | github.com/bnb-chain/tss-lib | <=1.3.5 |
no fix listed |
Classification
- Weakness
-
- CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
References
Sources
- GitHub Advisory GHSA-h24c-6p6p-m3vx
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