Authorization Bypass Affecting istio.io/istio/pilot/pkg/security/authz/matcher package, versions >=1.11.0 <1.11.1>=1.10.0 <1.10.4<1.9.8


Severity

Recommended
0.0
high
0
10

CVSS assessment made by Snyk's Security Team. Learn more

Threat Intelligence

EPSS
0.14% (51st percentile)

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  • Snyk IDSNYK-GOLANG-ISTIOIOISTIOPILOTPKGSECURITYAUTHZMATCHER-1569480
  • published25 Aug 2021
  • disclosed25 Aug 2021
  • creditYangmin Zhu of Google

Introduced: 25 Aug 2021

CVE-2021-39155  (opens in a new tab)
CWE-285  (opens in a new tab)

How to fix?

Upgrade istio.io/istio/pilot/pkg/security/authz/matcher to version 1.11.1, 1.10.4, 1.9.8 or higher.

Overview

istio.io/istio/pilot/pkg/security/authz/matcher is an An open platform to connect, manage, and secure microservices.

Affected versions of this package are vulnerable to Authorization Bypass. According to RFC 4343, Istio authorization policy should compare the hostname in the HTTP Host header in a case insensitive way, but currently the comparison is case sensitive. An HTTP request could potentially bypass an Istio authorization policy when using rules based on hosts or notHosts.

For example, the user could have an authorization policy that rejects requests with host secret.com, but the attacker can bypass this by sending the request with hostname Secret.com. The routing flow routes the traffic to the backend for secret.com which is a policy violation.

CVSS Scores

version 3.1