CVE-2020-15247: October/cms Twig Sandbox Escape By Authenticated Vulnerability

MODERATE
Advisory Identifier: GHSA-94vp-rmqv-5875
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CVSS 5.2
CWE-862
Published
Advisory Summary

CVE-2020-15247 is a MODERATE (CVSS 5.2) twig sandbox escape by authenticated vulnerability (CWE-862: Missing Authorization) affecting October/cms libraries in the Packagist ecosystem. The issue involves twig sandbox escape by authenticated users with access to editing cms templates when safemode is enabled.. Remediation is available by upgrading affected packages to version 1.0.469.

CVE-2020-15247 at a Glance

CVE Identifier CVE-2020-15247
GHSA Identifier GHSA-94vp-rmqv-5875
Severity MODERATE
CVSS v3.1 Base Score 5.2
CWE Classification CWE-862: Missing Authorization
Affected Product October/cms
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 5.2

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L).

Attack Vector Local (AV:L)
Attack Complexity Low (AC:L)
Privileges Required High (PR:H)
User Interaction Required (UI:R)
Scope Changed (S:C)
Confidentiality Low (C:L)
Integrity Low (I:L)
Availability Low (A:L)

How to Fix CVE-2020-15247

To remediate this vulnerability, upgrade all affected October/cms dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

october/cms fixed: 1.0.469 
Upgrade october/cms to 1.0.469
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for october/cms

How to Check if You Are Affected

To determine whether your application is affected by CVE-2020-15247, inspect your project dependencies for October/cms:

inspect dependencies for october/cms

Analyze the terminal output to locate any version of October/cms in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.0.469), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-862: Missing Authorization, where the product does not perform an authorization check when an actor attempts to access a resource or perform an action. In October/cms, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact An authenticated backend user with the `cms.manage_pages`, `cms.manage_layouts`, or `cms.manage_partials` permissions who would **normally** not be permitted to provide PHP code to be executed by the CMS due to `cms.enableSafeMode` being enabled is able to write specific Twig code to escape the Twig sandbox and execute arbitrary PHP. This is not a problem for anyone that trusts their users with those permissions to normally write & manage PHP within the CMS by not having `cms.enableSafeMode` enabled, but would be a problem for anyone relying on `cms.enableSafeMode` to ensure that users with those permissions in production do not have access to write & execute arbitrary PHP. ### Patches Issue has been patched in Build 469 (v1.0.469) and v1.1.0. ### Workarounds Apply https://github.com/octobercms/october/compare/106daa2930de4cebb18732732d47d4056f01dd5b...7cb148c1677373ac30ccfd3069d18098e403e1ca to your installation manually if unable to upgrade to Build 469. ### References Reported by [ka1n4t](https://github.com/ka1n4t) ### For more information If you have any questions or comments about this advisory: * Email us at [hello@octobercms.com](mailto:hello@octobercms.com) ### Threat assessment: <img width="1108" alt="Screen Shot 2020-10-10 at 1 21 13 PM" src="https://user-images.githubusercontent.com/7253840/95663316-7de28b80-0afb-11eb-999d-a6526cf78709.png">

CVE-2020-15247 Affected October/cms Versions

1 component(s)
Fixed Versions:
1.0.469
Product / Package Ecosystem Affected Versions Fixed Version
october/cms
 Packagist
≥ 1.0.319
< 1.0.469
1.0.469

References

GitHub Advisory / Wiki ADVISORY
https://github.com/octobercms/october/security/advisories/GHSA-94vp-rmqv-5875
NVD — CVE-2020-15247 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-15247
Security Fix Commit FIX COMMIT
https://github.com/octobercms/october/commit/4c650bb775ab849e48202a4923bac93bd74f9982
October/cms Source Repository REPOSITORY
https://github.com/octobercms/october

Frequently Asked Questions

What is CVE-2020-15247?
CVE-2020-15247 is a security vulnerability in October/cms involving Twig Sandbox Escape by authenticated users with access to editing CMS templates when safemode is enabled. under CWE-862: Missing Authorization.
Which October/cms versions are affected?
Affected versions include releases prior to 1.0.469 across affected packages: october/cms.
What version fixes CVE-2020-15247?
Upgrading to 1.0.469 (or the latest patched release for your respective branch) resolves the vulnerability.
Is october/cms affected?
Yes, october/cms is affected in releases prior to 1.0.469. Upgrade your dependency to 1.0.469 or later.
What is the CVSS score of CVE-2020-15247?
CVE-2020-15247 has a CVSS v3.1 base score of 5.2 (MODERATE) with vector string CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L.
What CWE is associated with CVE-2020-15247?
CVE-2020-15247 is classified under CWE-862: Missing Authorization (The product does not perform an authorization check when an actor attempts to access a resource or perform an action.).
How can I check Packagist dependencies for CVE-2020-15247?
Run the dependency tree command: 'inspect dependencies for october/cms'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-94vp-rmqv-5875",
  "modified" : "2021-11-19T13:42:37Z",
  "published" : "2020-11-23T19:48:27Z",
  "aliases" : [ "CVE-2020-15247" ],
  "summary" : "Twig Sandbox Escape by authenticated users with access to editing CMS templates when safemode is enabled.",
  "details" : "### Impact\nAn authenticated backend user with the `cms.manage_pages`, `cms.manage_layouts`, or `cms.manage_partials` permissions who would **normally** not be permitted to provide PHP code to be executed by the CMS due to `cms.enableSafeMode` being enabled is able to write specific Twig code to escape the Twig sandbox and execute arbitrary PHP.\n\nThis is not a problem for anyone that trusts their users with those permissions to normally write & manage PHP within the CMS by not having `cms.enableSafeMode` enabled, but would be a problem for anyone relying on `cms.enableSafeMode` to ensure that users with those permissions in production do not have access to write & execute arbitrary PHP.\n\n### Patches\nIssue has been patched in Build 469 (v1.0.469) and v1.1.0.\n\n### Workarounds\nApply https://github.com/octobercms/october/compare/106daa2930de4cebb18732732d47d4056f01dd5b...7cb148c1677373ac30ccfd3069d18098e403e1ca to your installation manually if unable to upgrade to Build 469.\n\n### References\nReported by [ka1n4t](https://github.com/ka1n4t)\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Email us at [hello@octobercms.com](mailto:hello@octobercms.com)\n\n### Threat assessment:\n<img width=\"1108\" alt=\"Screen Shot 2020-10-10 at 1 21 13 PM\" src=\"https://user-images.githubusercontent.com/7253840/95663316-7de28b80-0afb-11eb-999d-a6526cf78709.png\">",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "october/cms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.0.319"
      }, {
        "fixed" : "1.0.469"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/octobercms/october/security/advisories/GHSA-94vp-rmqv-5875"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-15247"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/octobercms/october/commit/4c650bb775ab849e48202a4923bac93bd74f9982"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/octobercms/october"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-862" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2020-11-23T19:33:21Z",
    "nvd_published_at" : "2020-11-23T20:15:00Z"
  }
}