CVE-2021-3827

Description

A flaw was found in keycloak, where the default ECP binding flow allows other authentication flows to be bypassed. By exploiting this behavior, an attacker can bypass the MFA authentication by sending a SOAP request with an AuthnRequest and Authorization header with the user's credentials. The highest threat from this vulnerability is to confidentiality and integrity.

Common Vulnerability Scoring System (CVSS) Score Details

Info alert:Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).

CVSS v3 Score Breakdown

Red HatNVDcve.org
Base Score6.86.8N/A
Attack VectorNetworkNetworkN/A
Attack ComplexityHighHighN/A
Privileges RequiredLowLowN/A
User InteractionNoneNoneN/A
ScopeUnchangedUnchangedN/A
ConfidentialityHighHighN/A
Integrity ImpactHighHighN/A
Availability ImpactNoneNoneN/A

Vector

Red Hat: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N

NVD: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N

Red Hat CVSS v3 Score Explanation

Attack complexity is 'High', because an attacker still need to pass first level of authentication using the authorization header in the SOAP request.

Understanding the Weakness (CWE)

CWE-287

Integrity,Confidentiality,Availability,Access Control

Technical Impact: Read Application Data; Gain Privileges or Assume Identity; Execute Unauthorized Code or Commands

This weakness can lead to the exposure of resources or functionality to unintended actors, possibly providing attackers with sensitive information or even execute arbitrary code.

Acknowledgements

Red Hat would like to thank Aaron Sachau (SRAM) for reporting this issue.

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