Upstream information
Description
Generating the ECDSA nonce k samples a random number r and thentruncates 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.
SUSE information
Overall state of this security issue: Does not affect SUSE products
This issue is currently rated as having moderate severity.
| CVSS detail | CNA (facts@wolfssl.com) | National Vulnerability Database |
|---|---|---|
| Base Score | 4.1 | 4.9 |
| Vector | CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N |
| Attack Vector | Local | Network |
| Attack Complexity | High | Low |
| Privileges Required | High | High |
| User Interaction | None | None |
| Scope | Unchanged | Unchanged |
| Confidentiality Impact | High | High |
| Integrity Impact | None | None |
| Availability Impact | None | None |
| CVSSv3 Version | 3.1 | 3.1 |
SUSE Timeline for this CVE
CVE page created: Tue Aug 27 22:00:34 2024CVE page last modified: Sat Dec 6 12:13:05 2025