Instituto Nacional de ciberseguridad. Sección Incibe
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CVE-2021-32777

Severity CVSS v4.0:
Pending analysis
Type:
Unavailable / Other
Publication date:
24/08/2021
Last modified:
15/06/2022

Description

Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. In affected versions when ext-authz extension is sending request headers to the external authorization service it must merge multiple value headers according to the HTTP spec. However, only the last header value is sent. This may allow specifically crafted requests to bypass authorization. Attackers may be able to escalate privileges when using ext-authz extension or back end service that uses multiple value headers for authorization. A specifically constructed request may be delivered by an untrusted downstream peer in the presence of ext-authz extension. Envoy versions 1.19.1, 1.18.4, 1.17.4, 1.16.5 contain fixes to the ext-authz extension to correctly merge multiple request header values, when sending request for authorization.

Impact

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

Base Score: 8.30 HIGH
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L

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

Base Score 3.x
8.30
Severity 3.x
HIGH
Vector 2.0
AV:N/AC:L/Au:N/C:P/I:P/A:P CVSS v2.0 Severity and Metrics:

Base Score: 7.50 HIGH
Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P

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

Base Score 2.0
7.50
Severity 2.0
HIGH

Vulnerable products and versions

CPE From Up to
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* 1.16.0 (including) 1.16.5 (excluding)
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* 1.17.0 (including) 1.17.4 (excluding)
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* 1.18.0 (including) 1.18.4 (excluding)
cpe:2.3:a:envoyproxy:envoy:1.19.0:*:*:*:*:*:*:*

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


References to Advisories, Solutions, and Tools