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Kanister vulnerable to cluster-level privilege escalation

Moderate severity GitHub Reviewed Published Aug 20, 2024 in kanisterio/kanister • Updated Nov 7, 2024

Package

gomod github.com/kanisterio/kanister (Go)

Affected versions

<= 0.0.0-20240820151504-314b65d5d9ab

Patched versions

None

Description

Details

The kanister has a deployment called default-kanister-operator, which is bound with a ClusterRole called edit via ClusterRoleBinding(https://github.com/kanisterio/kanister/blob/master/helm/kanister-operator/templates/rbac.yaml#L49). The "edit" ClusterRole is one of Kubernetes default-created ClusterRole, and it have create/patch/udpate verbs of daemonset resources, create verb of serviceaccount/token resources, and impersonate verb of serviceaccounts resources. If a malicious user can access the worker node which has this component, he/she can:

For the create/patch/update verbs of daemonset resources, the malicious user can abuse it to create or modify a set of Pods to mount a high-privilege service account (e.g., the cluster-admin service account). After that, he/she can abuse the high-privilege SA token of created Pod to take over the whole cluster.

For the create verb of serviceaccount/token resources, a malicious user can abuse this permission to generate new Service Account tokens and use them to operate with high-privilege roles, such as cluster administrators. These tokens can be used to access and manipulate any resources within the cluster.

For the impersonate verb of serviceaccounts resources, a malicious user can impersonate high-privilege Service Accounts, thereby gaining access to roles such as cluster administrators. This enables the attacker to perform all actions that the high-privilege account can, including creating, modifying, and deleting critical resources within the cluster.

PoC

We have discussed in the "Details" section

Impact

Privilege escalation

Mitigation

Currently kanister helm chart provides rbac.create flag (true by default), which controls whether the rbac rules for kanister service account will be created https://github.com/kanisterio/kanister/blob/master/helm/kanister-operator/values.yaml#L17
If this value set to false, the user needs to create rbac rules themselves and they can limit the role bindings for kanister service account, for example scope it to specific namespace.
Service account can also be configured via helm https://github.com/kanisterio/kanister/blob/master/helm/kanister-operator/values.yaml#L19

References

@hairyhum hairyhum published to kanisterio/kanister Aug 20, 2024
Published to the GitHub Advisory Database Aug 20, 2024
Reviewed Aug 20, 2024
Published by the National Vulnerability Database Aug 20, 2024
Last updated Nov 7, 2024

Severity

Moderate

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 None
Integrity None
Availability None

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:N/SI:N/SA:N/E:U

EPSS score

0.043%
(10th percentile)

Weaknesses

CVE ID

CVE-2024-43403

GHSA ID

GHSA-h27c-6xm3-mcqp

Source code

Credits

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