Vulnerability in Arm Mbed TLS
CVE-2020-10932
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.7 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.003 (14.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 15th percentile — 14.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- Arm Mbed TLS
- Trustedfirmware Mbed TLS
- Debian Linux — versions 10.0
- Fedoraproject Fedora — versions 31, 32
Weakness classification (CWE)
Public proof-of-concept exploits
References
- tls.mbed.org/tech-updates/security-advisories (Vendor Advisory)
- tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2020-04 (Vendor Advisory)
- tls.mbed.org/tech-updates/releases/mbedtls-2.16.6-and-2.7.15-released (Release Notes)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory, Mailing List, Third Party Advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory, Mailing List, Third Party Advisory)
- lists.debian.org/debian-lts-announce/2022/12/msg00036.html (mailing-list, Mailing List, Third Party Advisory)
Frequently asked questions
- What is CVE-2020-10932?
- CVE-2020-10932 is a medium-severity vulnerability in Arm Mbed TLS, classified under Observable Discrepancy. CVSS score: 4.7/10. Published 2020-04-15.
- How severe is CVE-2020-10932?
- Medium severity. CVSS v3 base score is 4.7 out of 10.
- Is CVE-2020-10932 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.