// For flags

CVE-2024-1544

ECDSA nonce bias caused by truncation

Severity Score

4.1
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

Track
*SSVC
Descriptions

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.

*Credits: Florian Sieck, Luca Wilke and Thomas Eisenbarth from Universität zu Lübeck
CVSS Scores
Attack Vector
Local
Attack Complexity
High
Privileges Required
High
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:Track
Exploitation
None
Automatable
No
Tech. Impact
Partial
* Organization's Worst-case Scenario
Timeline
  • 2024-02-15 CVE Reserved
  • 2024-08-27 CVE Published
  • 2024-08-27 CVE Updated
  • 2024-08-28 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-203: Observable Discrepancy
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
WolfSSL
Search vendor "WolfSSL"
WolfSSL
Search vendor "WolfSSL" for product "WolfSSL"
<= 5.6.4
Search vendor "WolfSSL" for product "WolfSSL" and version " <= 5.6.4"
en
Affected