Candlepin: consumer certificate can register systems in another organization

Overview

A missing authorization check has been found in ConsumerResource.setupOwner() function of consumer registration module in the Candlepin package. The registration method checks permission to create a consumer only when the caller is a user. A consumer that authenticates with its identity certificate does not go through that check. A low-privileged network attacker or user who has a valid consumer certificate for one organization can register a new consumer in a different organization by supplying that organization's key. The response includes an identity certificate for the new consumer. With that certificate, the attacker can view the target organization's subscription pools. When the organization is not using simple content access, the attacker can attach that organization's entitlements to the new consumer.

Affected

• candlepin (all versions)
• candlepin (all versions)
• candlepin (all versions)
• candlepin (all versions)
• candlepin (all versions)

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

Workarounds

There is no configuration switch that stops a consumer certificate from calling registration while leaving normal consumer check-ins working. Restricting which clients can reach the Candlepin port limits who can attempt the call, and it does not stop a client that already has a valid consumer certificate and is allowed to use the API. Customers are advised to apply the relevant security updates when they become available.