Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

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CVE-2020-15104

Severity CVSS v4.0:
Pending analysis
Type:
Unavailable / Other
Publication date:
14/07/2020
Last modified:
21/07/2020

Description

In Envoy before versions 1.12.6, 1.13.4, 1.14.4, and 1.15.0 when validating TLS certificates, Envoy would incorrectly allow a wildcard DNS Subject Alternative Name apply to multiple subdomains. For example, with a SAN of *.example.com, Envoy would incorrectly allow nested.subdomain.example.com, when it should only allow subdomain.example.com. This defect applies to both validating a client TLS certificate in mTLS, and validating a server TLS certificate for upstream connections. This vulnerability is only applicable to situations where an untrusted entity can obtain a signed wildcard TLS certificate for a domain of which you only intend to trust a subdomain of. For example, if you intend to trust api.mysubdomain.example.com, and an untrusted actor can obtain a signed TLS certificate for *.example.com or *.com. Configurations are vulnerable if they use verify_subject_alt_name in any Envoy version, or if they use match_subject_alt_names in version 1.14 or later. This issue has been fixed in Envoy versions 1.12.6, 1.13.4, 1.14.4, 1.15.0.

Impact

Vector 3.x
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N CVSS v3.1 Severity and Metrics:

Base Score: 5.40 MEDIUM
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): Low
Integrity (I): Low
Availability (A): None

Base Score 3.x
5.40
Severity 3.x
MEDIUM
Vector 2.0
AV:N/AC:L/Au:S/C:P/I:P/A:N CVSS v2.0 Severity and Metrics:

Base Score: 5.50 MEDIUM
Vector: AV:N/AC:L/Au:S/C:P/I:P/A:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Authentication (Au): Single
Confidentiality (C): Physical
Integrity (I): Physical
Availability (A): None

Base Score 2.0
5.50
Severity 2.0
MEDIUM

Vulnerable products and versions

CPE From Up to
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* 1.12.6 (excluding)
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* 1.13.0 (including) 1.13.4 (excluding)
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* 1.14.0 (including) 1.14.4 (excluding)

To consult the complete list of CPE names with products and versions, see this page


References to Advisories, Solutions, and Tools