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CA certificate check bypass with X509_V_FLAG_X509_STRICT (OpenSSL OpenSSL)

CVE-2021-3450
HIGH 7.4

En bref

Source
NVD
EPSS
EPSS 18.34 % · centile 97 ()
État
PUBLISHED
Publiée
Mise à jour
Attribuée par
openssl
Statut NVD
Modified

Rechercher sur…

Description

The X509_V_FLAG_X509_STRICT flag enables additional security checks of the certificates present in a certificate chain. It is not set by default. Starting from OpenSSL version 1.1.1h a check to disallow certificates in the chain that have explicitly encoded elliptic curve parameters was added as an additional strict check. An error in the implementation of this check meant that the result of a previous check to confirm that certificates in the chain are valid CA certificates was overwritten. This effectively bypasses the check that non-CA certificates must not be able to issue other certificates. If a "purpose" has been configured then there is a subsequent opportunity for checks that the certificate is a valid CA. All of the named "purpose" values implemented in libcrypto perform this check. Therefore, where a purpose is set the certificate chain will still be rejected even when the strict flag has been used. A purpose is set by default in libssl client and server certificate verification routines, but it can be overridden or removed by an application. In order to be affected, an application must explicitly set the X509_V_FLAG_X509_STRICT verification flag and either not set a purpose for the certificate verification or, in the case of TLS client or server applications, override the default purpose. OpenSSL versions 1.1.1h and newer are affected by this issue. Users of these versions should upgrade to OpenSSL 1.1.1k. OpenSSL 1.0.2 is not impacted by this issue. Fixed in OpenSSL 1.1.1k (Affected 1.1.1h-1.1.1j).

Faiblesses (CWE)

  • CWE-295 — Validation incorrecte de certificat

Références

Scores

VersionScoreVecteurÉvalué par
CVSS 3.1HIGH 7.4CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:NNVD · nvd@nist.gov (Primary)
CVSS 2.0MEDIUM 5.8AV:N/AC:M/Au:N/C:P/I:P/A:NNVD · nvd@nist.gov (Primary)

Références européennes

Avis du CERT-FR

Configurations affectées (CPE NVD)

Produits affectés

ProduitVersions
OpenSSL · OpenSSLaffected Fixed in OpenSSL 1.1.1k (Affected 1.1.1h-1.1.1j)

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD