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Rancher vulnerable to Privilege Escalation via manipulation of Secrets

Critical severity GitHub Reviewed Published Jun 1, 2023 in rancher/rancher • Updated Oct 9, 2024

Package

gomod github.com/rancher/rancher (Go)

Affected versions

>= 2.6.0, < 2.6.13
>= 2.7.0, < 2.7.4

Patched versions

2.6.13
2.7.4

Description

Impact

A vulnerability has been identified which enables Standard users or above to elevate their permissions to Administrator in the local cluster.

The local cluster means the cluster where Rancher is installed. It is named local inside the list of clusters in the Rancher UI.

Standard users could leverage their existing permissions to manipulate Kubernetes secrets in the local cluster, resulting in the secret being deleted, but their read-level permissions to the secret being preserved. When this operation was followed-up by other specially crafted commands, it could result in the user gaining access to tokens belonging to service accounts in the local cluster.

Users that have custom global roles which grant create and delete permissions on secrets would also be able to exploit this vulnerability.

Users with audit logs enabled in Rancher can try to identify possible abuses of this issue by going through the logs. To sieve through the data filter by kind: Secret with type: provisioning.cattle.io/cloud-credential, then investigate all log entries that affect that specific resource. A secondary check would be to filter by all operations with Opaque Secrets within the cattle-global-data namespace.

After patching, it is recommended that users review access methods to Rancher (including RBAC policies, tokens, and host-level node access), to ensure that no changes were made to persist access to users who have leveraged this vulnerability.

Patches

Patched versions include releases 2.6.13, 2.7.4 and later versions.

Workarounds

There is no direct mitigation besides updating Rancher to a patched version.

For more information

If you have any questions or comments about this advisory:

References

@macedogm macedogm published to rancher/rancher Jun 1, 2023
Published by the National Vulnerability Database Jun 1, 2023
Published to the GitHub Advisory Database Jun 6, 2023
Reviewed Jun 6, 2023
Last updated Oct 9, 2024

Severity

Critical

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v4 base metrics

Exploitability Metrics
Attack Vector Network
Attack Complexity Low
Attack Requirements None
Privileges Required Low
User interaction None
Vulnerable System Impact Metrics
Confidentiality High
Integrity High
Availability High
Subsequent System Impact Metrics
Confidentiality High
Integrity High
Availability High

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

EPSS score

0.043%
(10th percentile)

Weaknesses

CVE ID

CVE-2023-22647

GHSA ID

GHSA-p976-h52c-26p6

Source code

Credits

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