Authorization bypass in Istio

Published: 2021-05-25

Risk	High
Patch available	YES
Number of vulnerabilities	2
CVE-ID	CVE-2021-31921 CVE-2021-31920
CWE-ID	CWE-285
Exploitation vector	Network
Public exploit	N/A
Vulnerable software Subscribe	Istio Web applications / Other software
Vendor	Istio

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Improper Authorization

EUVDB-ID: #VU53523

Risk: High

CVSSv3.1: 8.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-31921

CWE-ID: CWE-285 - Improper Authorization

Exploit availability: No

Description

The vulnerability allows a remote attacker to bypass authorization procedure.

The vulnerability exists due to a logic issue when the istio gateway is configured with TLS mode `AUTO_PASSTHROUGH`. A remote non-authenticated attacker can bypass authorization checks and gain unauthorized access to services in the cluster.

Successful exploitation of the vulnerability may allow an attacker to compromise the affected system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Istio: 0.1 - 1.10.0

External links

http://istio.io/latest/news/security/istio-security-2021-006/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

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

2) Improper Authorization

EUVDB-ID: #VU53524

Risk: High

CVSSv3.1: 7.1 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-31920