CVE-2020-16844 : Exploit Details and Defense Strategies

In Istio 1.5.0 through 1.5.8 and Istio 1.6.0 through 1.6.7, an issue exists where users specifying an AuthorizationPolicy resource with DENY actions using wildcard suffixes may inadvertently allow access, bypassing intended policies.

Understanding CVE-2020-16844

This CVE highlights a vulnerability in Istio versions 1.5.0 to 1.5.8 and 1.6.0 to 1.6.7 that could lead to unauthorized access due to a specific configuration.

What is CVE-2020-16844?

The vulnerability arises when DENY actions with wildcard suffixes are used in AuthorizationPolicy resources, potentially granting access that should be restricted.

The Impact of CVE-2020-16844

The issue allows callers to bypass intended policies, leading to unauthorized access and potential security breaches.

Technical Details of CVE-2020-16844

This section delves into the specifics of the vulnerability.

Vulnerability Description

The vulnerability in Istio versions 1.5.0 to 1.5.8 and 1.6.0 to 1.6.7 enables users to unintentionally grant access by using DENY actions with wildcard suffixes in AuthorizationPolicy resources.

Affected Systems and Versions

Istio 1.5.0 to 1.5.8
Istio 1.6.0 to 1.6.7

Exploitation Mechanism

By specifying DENY actions with wildcard suffixes in source principals or namespace fields, callers can exploit the vulnerability to gain unauthorized access.

Mitigation and Prevention

Protecting systems from this vulnerability requires specific actions.

Immediate Steps to Take

Upgrade Istio to versions beyond 1.6.7 to mitigate the issue.
Review and update AuthorizationPolicy resources to remove wildcard suffixes in DENY actions.

Long-Term Security Practices

Regularly monitor Istio security advisories and update systems promptly.
Implement least privilege access controls to limit potential vulnerabilities.

Patching and Updates

Stay informed about Istio security updates and apply patches promptly to address known vulnerabilities.