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Kirby has insufficient permission checks in the language settings

High severity GitHub Reviewed Published Aug 29, 2024 in getkirby/kirby • Updated Aug 29, 2024

Package

composer getkirby/cms (Composer)

Affected versions

<= 3.6.6.5
>= 3.7.0, <= 3.7.5.4
>= 3.8.0, <= 3.8.4.3
>= 3.9.0, <= 3.9.8.1
>= 3.10.0, <= 3.10.1
>= 4.0.0, <= 4.3.0

Patched versions

3.6.6.6
3.7.5.5
3.8.4.4
3.9.8.2
3.10.1.1
4.3.1

Description

TL;DR

This vulnerability affects all Kirby sites with enabled languages option that might have potential attackers in the group of authenticated Panel users.

If you have disabled the languages and/or api option and don't call any methods in your code that cause a write access to languages (language creation, update or deletion), your site is not affected.

Introduction

Kirby allows to restrict the permissions of specific user roles. Users of that role can only perform permitted actions.

Permissions for creating and deleting languages have already existed and could be configured, but were not enforced by Kirby's frontend or backend code.

A permission for updating existing languages has not existed before the patched versions. So disabling the languages.* wildcard permission for a role could not have prohibited updates to existing language definitions.

Impact

The missing permission checks allowed attackers with Panel access to manipulate the language definitions.

The language definitions are at the core of multi-language content in Kirby. Unauthorized modifications with malicious intent can cause significant damage, for example:

  • If the languages option was enabled but no language exists, creating the first language will switch Kirby to multi-language mode.
  • Deleting an existing language will lead to content loss of all translated content in that language. Deleting the last language will switch Kirby to single-language mode.
  • Updating a language allows to change the metadata including the language slug (used in page URLs) and language variables. It also allows to change the default language, which will cause Kirby to use the new default language's content as a fallback for non-existing translations.

Depending on the site code, the result of such actions can cause loss of site availability (e.g. error messages in the site frontend) or integrity (due to changed URLs or removed translations).

Patches

The problem has been patched in Kirby 3.6.6.6, Kirby 3.7.5.5, Kirby 3.8.4.4, Kirby 3.9.8.2, Kirby 3.10.1.1, and Kirby 4.3.1. Please update to one of these or a later version to fix the vulnerability.

In all of the mentioned releases, we have added checks for the languages.create and languages.delete permissions that ensure that users without those permissions cannot perform the respective actions. We have also added a new languages.update permission.

Credits

Thanks to Sebastian Eberlein of JUNO (@SebastianEberlein-JUNO) for reporting the identified issue.

References

@lukasbestle lukasbestle published to getkirby/kirby Aug 29, 2024
Published by the National Vulnerability Database Aug 29, 2024
Published to the GitHub Advisory Database Aug 29, 2024
Reviewed Aug 29, 2024
Last updated Aug 29, 2024

Severity

High

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 None
User interaction None
Vulnerable System Impact Metrics
Confidentiality None
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:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

EPSS score

0.046%
(18th percentile)

Weaknesses

CVE ID

CVE-2024-41964

GHSA ID

GHSA-jm9m-rqr3-wfmh

Source code

Credits

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