CVE-2020-9309: Silverstripe/cms Silverstripe CMS Malicious File Upload Vulnerability

HIGH
Advisory Identifier: GHSA-h77w-655f-6j3m
Share
CVSS 8.8
CWE-434
Published
Advisory Summary

CVE-2020-9309 is a HIGH (CVSS 8.8) silverstripe cms malicious file upload vulnerability (CWE-434: Unrestricted Upload of File with Dangerous Type) affecting Silverstripe/cms libraries in the Packagist ecosystem. The issue involves silverstripe cms malicious file upload enables script execution. Remediation is available in the latest vendor maintenance releases.

CVE-2020-9309 at a Glance

CVE Identifier CVE-2020-9309
GHSA Identifier GHSA-h77w-655f-6j3m
Severity HIGH
CVSS v3.1 Base Score 8.8
CWE Classification CWE-434: Unrestricted Upload of File with Dangerous Type
Affected Product Silverstripe/cms
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 8.8

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

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2020-9309

To remediate this vulnerability, upgrade all affected Silverstripe/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.

silverstripe/cms fixed: Latest secure release 
Upgrade silverstripe/cms to Latest secure release
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 silverstripe/cms

How to Check if You Are Affected

To determine whether your application is affected by CVE-2020-9309, inspect your project dependencies for Silverstripe/cms:

inspect dependencies for silverstripe/cms

Analyze the terminal output to locate any version of Silverstripe/cms in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), 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-434: Unrestricted Upload of File with Dangerous Type, where the product allows the upload or transfer of dangerous file types that are automatically processed within its environment. In Silverstripe/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

Silverstripe CMS through 4.5 can be susceptible to script execution from malicious upload contents under allowed file extensions (for example HTML code in a TXT file). When these files are stored as protected or draft files, the MIME detection can cause browsers to execute the file contents. Uploads stored as protected or draft files are allowed by default for authorised users only, but can also be enabled through custom logic as well as modules such as silverstripe/userforms. Sites using the previously optional silverstripe/mimevalidator module can configure MIME whitelists rather than extension whitelists, and hence prevent this issue. Sites on the Common Web Platform (CWP) use this module by default, and are not affected.

CVE-2020-9309 Affected Silverstripe/cms Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
silverstripe/cms
 Packagist
≤ 4.5.0

References

NVD — CVE-2020-9309 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-9309
Silverstripe/cms Source Repository REPOSITORY
https://github.com/silverstripe/silverstripe-cms
Silverstripe/cms Release RELEASE
https://www.silverstripe.org/download/security-releases/CVE-2020-9309

Frequently Asked Questions

What is CVE-2020-9309?
CVE-2020-9309 is a security vulnerability in Silverstripe/cms involving Silverstripe CMS malicious file upload enables script execution under CWE-434: Unrestricted Upload of File with Dangerous Type.
Which Silverstripe/cms versions are affected?
Affected versions include releases prior to current release patches across affected packages: silverstripe/cms.
What version fixes CVE-2020-9309?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is silverstripe/cms affected?
Yes, silverstripe/cms is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2020-9309?
CVE-2020-9309 has a CVSS v3.1 base score of 8.8 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2020-9309?
CVE-2020-9309 is classified under CWE-434: Unrestricted Upload of File with Dangerous Type (The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.).
How can I check Packagist dependencies for CVE-2020-9309?
Run the dependency tree command: 'inspect dependencies for silverstripe/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-h77w-655f-6j3m",
  "modified" : "2023-08-22T21:59:51Z",
  "published" : "2022-05-24T17:23:42Z",
  "aliases" : [ "CVE-2020-9309" ],
  "summary" : "Silverstripe CMS malicious file upload enables script execution",
  "details" : "Silverstripe CMS through 4.5 can be susceptible to script execution from malicious upload contents under allowed file extensions (for example HTML code in a TXT file). When these files are stored as protected or draft files, the MIME detection can cause browsers to execute the file contents. Uploads stored as protected or draft files are allowed by default for authorised users only, but can also be enabled through custom logic as well as modules such as silverstripe/userforms. Sites using the previously optional silverstripe/mimevalidator module can configure MIME whitelists rather than extension whitelists, and hence prevent this issue. Sites on the Common Web Platform (CWP) use this module by default, and are not affected.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "silverstripe/cms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "4.5.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-9309"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/silverstripe/silverstripe-cms"
  }, {
    "type" : "WEB",
    "url" : "https://www.silverstripe.org/download/security-releases/CVE-2020-9309"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-434" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-07-13T21:21:24Z",
    "nvd_published_at" : "2020-07-15T21:15:00Z"
  }
}