MFA authentication bypass in Keycloak

1) Authentication bypass using an alternate path or channel

EUVDB-ID: #VU59892

Risk: Medium

CVSSv3.1: 5.9 [CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-3827

CWE-ID: CWE-288 - Authentication Bypass Using an Alternate Path or Channel

Exploit availability: No

Description

The vulnerability allows a remote attacker to bypass 2FA authentication.

The vulnerability exists due to an error in ECP SAML binding flow within keycloak-server-spi-private. A remote attacker can send SOAP request with an AuthnRequest and Authorization header with the user's credentials and bypass MFA authentication.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Keycloak: 15.0.0 - 15.1.1

External links

http://bugzilla.redhat.com/show_bug.cgi?id=2007512

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.