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GHSA-qjvc-p88j-j9rm BIT-kyverno-2024-48921 CVE-2024-48921 GO-2024-3230

Kyverno's PolicyException objects can be created in any namespace by default

Low Go
Severity
0.0 / 10
Low · CVSS 4.0
Exploit chance (EPSS)
0.57%
Chance of exploitation in the next 30 days. Higher than 47.34% of scored vulnerabilities.
Known exploited
No
Not in CISA's catalog
Weakness
CWE-285 Improper Authorization
CWE-863 Incorrect Authorization
Fix
1.13.0
Upgrade github.com/kyverno/kyverno to this version or later

Description

Summary

A kyverno ClusterPolicy, ie. "disallow-privileged-containers," can be overridden by the creation of a PolicyException in a random namespace.

Details

By design, PolicyExceptions are consumed from any namespace. Administrators may not recognize that this allows users with privileges to non-kyverno namespaces to create exceptions.

PoC

  1. Administrator creates "disallow-privileged-containers" ClusterPolicy that applies to resources in the namespace "ubuntu-restricted"
  2. Cluster user creates a PolicyException object for "disallow-privileged-containers" in namespace "ubuntu-restricted"
  3. Cluster user creates a pod with a privileged container in "ubuntu-restricted"
  4. Cluster user escalates to root on the node from the privileged container

Impact

Administrators attempting to enforce cluster security through kyverno policies, but that allow less privileged users to create resources

Affected versions

Go

PackageVulnerableFixed in
github.com/kyverno/kyverno
< 1.13.0
1.13.0

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

github.com/kyverno/kyverno Go → 1.13.0

go
go get github.com/kyverno/kyverno@v1.13.0 && go mod tidy

Severity breakdown

CVSS 4.0 0.0

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Attack vector
Network
Attack complexity
Low
Attack requirements
None
Privileges required
None
User interaction
None
Confidentiality (vulnerable system)
None
Integrity (vulnerable system)
High
Availability (vulnerable system)
None
Confidentiality (subsequent systems)
None
Integrity (subsequent systems)
None
Availability (subsequent systems)
None

CVSS 3.1 7.5

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

Weakness

CWE-285: Improper Authorization

The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action.

How to prevent it
  • Architecture and Design: Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
  • Architecture and Design: Ensure that you perform access control checks related to your business logic. These checks may be different than the access control checks that you apply to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor.
  • Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
  • Architecture and Design: For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page. One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.
  • System Configuration, Installation: Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.

CWE-863: Incorrect Authorization

The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

How to prevent it
  • Architecture and Design: Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
  • Architecture and Design: Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor [REF-7].
  • Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
  • Architecture and Design: For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page. One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.
  • System Configuration, Installation: Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.

References

Timeline

  1. Published
  2. Last updated by the source
  3. Latest EPSS score
AdvisorySeverityWhy it's related
GHSA-79gf-7frw-68m9
Kyverno's NamespacedGeneratingPolicy generator.apply() namespace argument unvalidated -- background controller creates RoleBindings in any namespace including kube-system
Critical Also affects github.com/kyverno/kyverno
GHSA-fpjq-c37h-cqcv
Kyverno Controller Denial of Service via forEach Mutation Panic
High Also affects github.com/kyverno/kyverno
GHSA-8wfp-579w-6r25
Kyverno apiCall automatically forwards ServiceAccount token to external endpoints (credential leak)
High Also affects github.com/kyverno/kyverno
GHSA-f9g8-6ppc-pqq4
Kyverno: ServiceAccount token leaked to external servers via apiCall service URL
Critical Also affects github.com/kyverno/kyverno
GHSA-cvq5-hhx3-f99p
Kyverno: Cross-Namespace Read Bypasses RBAC Isolation (CVE-2026-22039 Incomplete Fix)
High Also affects github.com/kyverno/kyverno
GHSA-q93q-v844-jrqp
kyverno apicall servicecall implicit bearer token injection leaks kyverno serviceaccount token
High Also affects github.com/kyverno/kyverno
GHSA-fmqp-4wfc-w3v7
Kyverno APICall SSRF Vulnerability Leading to Multi-Tenant Isolation Breach
Medium Also affects github.com/kyverno/kyverno
GHSA-qr4g-8hrp-c4rw
Kyverno has unrestricted outbound requests in Kyverno apiCall enabling SSRF
High Also affects github.com/kyverno/kyverno
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