CVE-2022-23551: AAD Pod Identity obtaining token with backslash

Vulnerability summary

CVE-2022-23551 is a medium (CVSS 5.3) Incorrect Authorization vulnerability in azure aad-pod-identity. EPSS estimates a 0.76% chance of exploitation in the next 30 days, higher than 54.8% of scored vulnerabilities.

Timeline

1. 21-12-2022
   PublishedVulnerability first disclosed.
2. 15-04-2025
   Last modifiedVulnerability information updated.

Description

aad-pod-identity assigns Azure Active Directory identities to Kubernetes applications and has now been deprecated as of 24 October 2022. The NMI component in AAD Pod Identity intercepts and validates token requests based on regex. In this case, a token request made with backslash in the request (example: `/metadata/identity\oauth2\token/`) would bypass the NMI validation and be sent to IMDS allowing a pod in the cluster to access identities that it shouldn't have access to. This issue has been fixed and has been included in AAD Pod Identity release version 1.8.13. If using the AKS pod-managed identities add-on, no action is required. The clusters should now be running the version 1.8.13 release.

• CWE-863Incorrect AuthorizationThe 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.
• CWE-1259Improper Restriction of Security Token AssignmentThe System-On-A-Chip (SoC) implements a Security Token mechanism to differentiate what actions are allowed or disallowed when a transaction originates from an entity. However, the Security Tokens are improperly protected.