CVE intelligence and bounded remediation

CVE-2020-10932 — An issue was discovered in Arm Mbed TLS before 2.16.6 and 2.7.x before 2.7.15

Medium CVSS 4.7

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.

Severity
Medium
CVSS
4.7 (3.1)
Published
2020-04-15
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-203, CWE-327

Affected products

  • arm / mbed_tls
  • trustedfirmware / mbed_tls
  • fedoraproject / fedora / 31
  • fedoraproject / fedora / 32
  • debian / debian_linux / 10.0

Matched remediation archetype

Cryptography, certificate, signature, and channel validation

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Inventory affected algorithms, key uses, trust stores, certificate validation settings, random sources, and plaintext channels across clients and services.
  • Determine which secrets, identities, signatures, or data protections depend on the affected primitive or validation path.
  • Check debug, compatibility, fallback, and hostname or audience override settings in build and runtime configuration.

Remediate safely

  • Use a maintained platform cryptographic API with approved algorithms, modes, parameters, randomness, and full peer identity validation.
  • Remove insecure fallback and validation bypasses; separate keys by purpose and load them from managed secret storage.
  • Plan rotation or reissuance for affected keys, certificates, tokens, hashes, or ciphertext and document compatibility sequencing.

Authoritative sources

Complete CVE record and remediation plan

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