Vulnerability CVE-2020-10932


Published: 2020-04-15

Description:
An issue was discovered in Arm Mbed TLS before 2.16.6 and 2.7.x before 2.7.15. An attacker that can get precise enough side-channel measurements can recover the long-term ECDSA private key by (1) reconstructing the projective coordinate of the result of scalar multiplication by exploiting side channels in the conversion to affine coordinates; (2) using an attack described by Naccache, Smart, and Stern in 2003 to recover a few bits of the ephemeral scalar from those projective coordinates via several measurements; and (3) using a lattice attack to get from there to the long-term ECDSA private key used for the signatures. Typically an attacker would have sufficient access when attacking an SGX enclave and controlling the untrusted OS.

Type:

CWE-327

(Use of a Broken or Risky Cryptographic Algorithm)

CVSS2 => (AV:L/AC:M/Au:N/C:P/I:N/A:N)

CVSS Base Score
Impact Subscore
Exploitability Subscore
1.9/10
2.9/10
3.4/10
Exploit range
Attack complexity
Authentication
Local
Medium
No required
Confidentiality impact
Integrity impact
Availability impact
Partial
None
None
Affected software
ARM -> Mbed tls 

 References:
https://tls.mbed.org/tech-updates/releases/mbedtls-2.16.6-and-2.7.15-released
https://tls.mbed.org/tech-updates/security-advisories
https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2020-04

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