CVE-2020-16844: Istio.io/istio Authorization Bypass Vulnerability

MODERATE
Advisory Identifier: GHSA-82mm-ffjr-h86c
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CVSS 6.8
CWE-284
Published
Advisory Summary

CVE-2020-16844 is a MODERATE (CVSS 6.8) authorization bypass vulnerability (CWE-284: Improper Access Control) affecting Istio.io/istio libraries in the Go ecosystem. The issue involves authorization bypass in istio. Remediation is available by upgrading affected packages to version 1.5.9, 1.6.8.

CVE-2020-16844 at a Glance

CVE Identifier CVE-2020-16844
GHSA Identifier GHSA-82mm-ffjr-h86c
Severity MODERATE
CVSS v3.1 Base Score 6.8
CWE Classification CWE-284: Improper Access Control
Affected Product Istio.io/istio
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 6.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2020-16844

To remediate this vulnerability, upgrade all affected Istio.io/istio dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

istio.io/istio fixed: 1.5.9 
Upgrade istio.io/istio to 1.5.9
istio.io/istio fixed: 1.6.8 
Upgrade istio.io/istio to 1.6.8
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for istio.io/istio

How to Check if You Are Affected

To determine whether your application is affected by CVE-2020-16844, inspect your project dependencies for Istio.io/istio:

inspect dependencies for istio.io/istio

Analyze the terminal output to locate any version of Istio.io/istio in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.5.9), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-284: Improper Access Control, where the product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. In Istio.io/istio, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

In Istio 1.5.0 though 1.5.8 and Istio 1.6.0 through 1.6.7, when users specify an AuthorizationPolicy resource with DENY actions using wildcard suffixes (e.g. *-some-suffix) for source principals or namespace fields, callers will never be denied access, bypassing the intended policy. ### Specific Go Packages Affected istio.io/istio/pilot/pkg/security/authz/model/matcher

CVE-2020-16844 Affected Istio.io/istio Versions

2 component(s)
Fixed Versions:
1.5.91.6.8
Product / Package Ecosystem Affected Versions Fixed Version
istio.io/istio
golang/istio.io/istio
Go
≥ 1.5.0
< 1.5.9
1.5.9
istio.io/istio
golang/istio.io/istio
Go
≥ 1.6.0
< 1.6.8
1.6.8

References

NVD — CVE-2020-16844 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-16844
Security Fix Commit FIX COMMIT
https://github.com/istio/istio/commit/4c73414556b83f0e75c1b3a0a89a23103a71573c
Security Fix Commit FIX COMMIT
https://github.com/istio/istio/commit/72d2e135374f421b656d6f1a21f474db46134ace
Istio.io/istio Source Repository REPOSITORY
https://github.com/istio/istio/releases
Istio.io/istio Release RELEASE
https://github.com/istio/istio/releases/tag/1.5.9
Istio.io/istio Release RELEASE
https://github.com/istio/istio/releases/tag/1.6.8
istio.io/latest/news/release... WEB
https://istio.io/latest/news/releases/1.5.x/announcing-1.5.9
istio.io/latest/news/release... WEB
https://istio.io/latest/news/releases/1.6.x/announcing-1.6.8
Istio.io/istio Security Information SECURITY
https://istio.io/latest/news/security/istio-security-2020-009

Frequently Asked Questions

What is CVE-2020-16844?
CVE-2020-16844 is a security vulnerability in Istio.io/istio involving Authorization bypass in Istio under CWE-284: Improper Access Control.
Which Istio.io/istio versions are affected?
Affected versions include releases prior to 1.5.9, 1.6.8 across affected packages: istio.io/istio.
What version fixes CVE-2020-16844?
Upgrading to 1.5.9, 1.6.8 (or the latest patched release for your respective branch) resolves the vulnerability.
Is istio.io/istio affected?
Yes, istio.io/istio is affected in releases prior to 1.5.9, 1.6.8. Upgrade your dependency to 1.5.9, 1.6.8 or later.
What is the CVSS score of CVE-2020-16844?
CVE-2020-16844 has a CVSS v3.1 base score of 6.8 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N.
What CWE is associated with CVE-2020-16844?
CVE-2020-16844 is classified under CWE-284: Improper Access Control (The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.).
How can I check Go dependencies for CVE-2020-16844?
Run the dependency tree command: 'inspect dependencies for istio.io/istio'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-82mm-ffjr-h86c",
  "modified" : "2023-10-02T13:07:29Z",
  "published" : "2022-02-15T01:57:18Z",
  "aliases" : [ "CVE-2020-16844" ],
  "summary" : "Authorization bypass in Istio",
  "details" : "In Istio 1.5.0 though 1.5.8 and Istio 1.6.0 through 1.6.7, when users specify an AuthorizationPolicy resource with DENY actions using wildcard suffixes (e.g. *-some-suffix) for source principals or namespace fields, callers will never be denied access, bypassing the intended policy.\n\n### Specific Go Packages Affected\nistio.io/istio/pilot/pkg/security/authz/model/matcher",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "istio.io/istio"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.5.0"
      }, {
        "fixed" : "1.5.9"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "istio.io/istio"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.6.0"
      }, {
        "fixed" : "1.6.8"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-16844"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/istio/istio/commit/4c73414556b83f0e75c1b3a0a89a23103a71573c"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/istio/istio/commit/72d2e135374f421b656d6f1a21f474db46134ace"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/istio/istio/releases"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/istio/istio/releases/tag/1.5.9"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/istio/istio/releases/tag/1.6.8"
  }, {
    "type" : "WEB",
    "url" : "https://istio.io/latest/news/releases/1.5.x/announcing-1.5.9"
  }, {
    "type" : "WEB",
    "url" : "https://istio.io/latest/news/releases/1.6.x/announcing-1.6.8"
  }, {
    "type" : "WEB",
    "url" : "https://istio.io/latest/news/security/istio-security-2020-009"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-284" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-05-12T21:59:07Z",
    "nvd_published_at" : null
  }
}