CVE-2021-32779
Assigner: GitHub_M
Published: 2021-08-24T20:45:09
State: PUBLISHED
affected: product: envoy
vendor: envoyproxy
versions: status: affected
version: >= 1.19.0, < 1.19.1
status: affected
version: >= 1.18.0, < 1.18.4
status: affected
version: >= 1.17.0, < 1.17.4
status: affected
version: >= 1.16.0, < 1.16.5
descriptions: value: Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. In affected versions envoy incorrectly handled a URI '#fragment' element as part of the path element. Envoy is configured with an RBAC filter for authorization or similar mechanism with an explicit case of a final "/admin" path element, or is using a negative assertion with final path element of "/admin". The client sends request to "/app1/admin#foo". In Envoy prior to 1.18.0, or 1.18.0+ configured with path_normalization=false. Envoy treats fragment as a suffix of the query string when present, or as a suffix of the path when query string is absent, so it evaluates the final path element as "/admin#foo" and mismatches with the configured "/admin" path element. In Envoy 1.18.0+ configured with path_normalization=true. Envoy transforms this to /app1/admin%23foo and mismatches with the configured /admin prefix. The resulting URI is sent to the next server-agent with the offending "#foo" fragment which violates RFC3986 or with the nonsensical "%23foo" text appended. A specifically constructed request with URI containing '#fragment' element delivered by an untrusted client in the presence of path based request authorization resulting in escalation of Privileges when path based request authorization extensions. Envoy versions 1.19.1, 1.18.4, 1.17.4, 1.16.5 contain fixes that removes fragment from URI path in incoming requests.
metrics: cvssV3_1: attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: NONE
baseScore: 8.6
baseSeverity: HIGH
confidentialityImpact: HIGH
integrityImpact: NONE
privilegesRequired: NONE
scope: CHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
version: 3.1
problemTypes: descriptions: cweId: CWE-551
description: CWE-551: Incorrect Behavior Order: Authorization Before Parsing and Canonicalization
type: CWE
descriptions: cweId: CWE-863
description: CWE-863: Incorrect Authorization
type: CWE
source: advisory: GHSA-r222-74fw-jqr9
discovery: UNKNOWN
title: Incorrectly handling of URI '#fragment' element as part of the path element