CVE-2024-1544
Generating the ECDSA nonce k samples a random number r and then truncates this randomness with a modular reduction mod n where n is the order of the elliptic curve.
Does this matter?
Lower severity and a low EPSS score (0.35%). Track it; it rarely justifies an emergency change on its own.
Description
Generating the ECDSA nonce k samples a random number r and then truncates this randomness with a modular reduction mod n where n is the order of the elliptic curve. Meaning k = r mod n. The division used during the reduction estimates a factor q_e by dividing the upper two digits (a digit having e.g. a size of 8 byte) of r by the upper digit of n and then decrements q_e in a loop until it has the correct size. Observing the number of times q_e is decremented through a control-flow revealing side-channel reveals a bias in the most significant bits of k. Depending on the curve this is either a negligible bias or a significant bias large enough to reconstruct k with lattice reduction methods. For SECP160R1, e.g., we find a bias of 15 bits.
- CVSS 3.1
- 4.9 MEDIUMCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 0.35% probability · 28th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-203
- Affected
- wolfssl/wolfssl
- Source
- facts@wolfssl.com
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.