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Camaleon CMS vulnerable to remote code execution through code injection (GHSL-2024-185)

High severity GitHub Reviewed Published Sep 18, 2024 in owen2345/camaleon-cms • Updated Sep 18, 2024

Package

bundler camaleon_cms (RubyGems)

Affected versions

< 2.8.1

Patched versions

2.8.1

Description

The actions defined inside of the MediaController class do not check whether a given path is inside a certain path (e.g. inside the media folder). If an attacker performed an account takeover of an administrator account (See: GHSL-2024-184) they could delete arbitrary files or folders on the server hosting Camaleon CMS. The crop_url action might make arbitrary file writes (similar impact to GHSL-2024-182) for any authenticated user possible, but it doesn't seem to work currently.

Arbitrary file deletion can be exploited with following code path: The parameter folder flows from the actions method:

  def actions
    authorize! :manage, :media if params[:media_action] != 'crop_url'
    params[:folder] = params[:folder].gsub('//', '/') if params[:folder].present?
    case params[:media_action]
    [..]
    when 'del_file'
      cama_uploader.delete_file(params[:folder].gsub('//', '/'))
      render plain: ''

into the method delete_file of the CamaleonCmsLocalUploader class (when files are uploaded locally):

def delete_file(key)
  file = File.join(@root_folder, key)
  FileUtils.rm(file) if File.exist? file
  @instance.hooks_run('after_delete', key)
  get_media_collection.find_by_key(key).take.destroy
end

Where it is joined in an unchecked manner with the root folder and then deleted.

Proof of concept
The following request would delete the file README.md in the top folder of the Ruby on Rails application. (The values for auth_token, X-CSRF-Token and _cms_session would also need to be replaced with authenticated values in the curl command below)

curl --path-as-is -i -s -k -X $'POST' \
    -H $'X-CSRF-Token: [..]' -H $'User-Agent: Mozilla/5.0' -H $'Content-Type: application/x-www-form-urlencoded; charset=UTF-8' -H $'Accept: */*' -H $'Connection: keep-alive' \
    -b $'auth_token=[..]; _cms_session=[..]' \
    --data-binary $'versions=&thumb_size=&formats=&media_formats=&dimension=&private=&folder=..%2F..%2F..%2FREADME.md&media_action=del_file' \
    $'https://<camaleon-host>/admin/media/actions?actions=true'

Impact
This issue may lead to a defective CMS or system.

Remediation
Normalize all file paths constructed from untrusted user input before using them and check that the resulting path is inside the targeted directory. Additionally, do not allow character sequences such as .. in untrusted input that is used to build paths.

See also:

CodeQL: Uncontrolled data used in path expression
OWASP: Path Traversal

References

@owen2345 owen2345 published to owen2345/camaleon-cms Sep 18, 2024
Published to the GitHub Advisory Database Sep 18, 2024
Reviewed Sep 18, 2024
Last updated Sep 18, 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 High
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:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Weaknesses

CVE ID

No known CVE

GHSA ID

GHSA-7x4w-cj9r-h4v9

Source code

Credits

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