Vulnerability CVE-2021-43824

Vulnerability Name:

CVE-2021-43824 (CCN-220194)

Assigned:

2021-11-16

Published:

2022-02-22

Updated:

2022-03-01

Summary:

Envoy is an open source edge and service proxy, designed for cloud-native applications. In affected versions a crafted request crashes Envoy when a CONNECT request is sent to JWT filter configured with regex match. This provides a denial of service attack vector. The only workaround is to not use regex in the JWT filter. Users are advised to upgrade.

CVSS v3 Severity:

7.5 High (CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
6.5 Medium (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C)

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

6.5 Medium (CCN CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H)
5.7 Medium (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C)

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

CVSS v2 Severity:

4.3 Medium (CVSS v2 Vector: AV:N/AC:M/Au:N/C:N/I:N/A:P)

Exploitability Metrics:	Access Vector (AV): Network Access Complexity (AC): Medium Authentication (Au): None
Impact Metrics:	Confidentiality (C): None Integrity (I): None Availibility (A): Partial

6.8 Medium (CCN CVSS v2 Vector: AV:N/AC:L/Au:S/C:N/I:N/A:C)

Exploitability Metrics:	Access Vector (AV): Network Access Complexity (AC): Low Athentication (Au): Single_Instance
Impact Metrics:	Confidentiality (C): None Integrity (I): None Availibility (A): Complete

Vulnerability Type:

CWE-476

Vulnerability Consequences:

Denial of Service

References:

Source: MITRE
Type: CNA
CVE-2021-43824

Source: XF
Type: UNKNOWN
envoy-cve202143824-dos(220194)

Source: MISC
Type: Patch, Third Party Advisory
https://github.com/envoyproxy/envoy/commit/9371333230b1a6e1be2eccf4868771e11af6253a

Source: CCN
Type: Envoy GIT Repository
Potential null pointer dereference when using JWT filter safe_regex match

Source: CONFIRM
Type: Issue Tracking, Third Party Advisory
https://github.com/envoyproxy/envoy/security/advisories/GHSA-vj5m-rch8-5r2p

Source: CCN
Type: WhiteSource Vulnerability Database
CVE-2021-43824

Vulnerable Configuration:

Configuration 1:

cpe:/a:envoyproxy:envoy:*:*:*:*:*:*:*:* (Version < 1.18.6)

OR cpe:/a:envoyproxy:envoy:*:*:*:*:*:*:*:* (Version >= 1.19.0 and < 1.19.3)

OR cpe:/a:envoyproxy:envoy:*:*:*:*:*:*:*:* (Version >= 1.20.0 and < 1.20.2)

OR cpe:/a:envoyproxy:envoy:*:*:*:*:*:*:*:* (Version >= 1.21.0 and < 1.21.1)

Denotes that component is vulnerable

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