CVE-2021-39184 : Exploit Details and Defense Strategies

Electron is a framework for writing cross-platform desktop applications. This vulnerability allows sandboxed renderers to request thumbnails of arbitrary files, potentially exposing sensitive data.

Understanding CVE-2021-39184

This CVE impacts Electron versions prior to 11.5.0, 12.1.0, and 13.3.0, allowing unauthorized access to file thumbnails.

What is CVE-2021-39184?

Vulnerability in Electron framework allowing renderers to request thumbnails of any file on the user's system
Versions 15.0.0-alpha.10, 14.0.0, 13.3.0, 12.1.0, and 11.5.0 have fixes
Two workarounds: enable

contextIsolation

or disable

createThumbnailFromPath

API

The Impact of CVE-2021-39184

CVSS v3.1 Base Score: 6.8 (Medium)
Attack Complexity: High, Attack Vector: Network
Confidentiality Impact: High, Integrity Impact: None

Technical Details of CVE-2021-39184

This section covers specifics of the vulnerability.

Vulnerability Description

Type: Exposure of Resource to Wrong Sphere (CWE-668)
Allows access to arbitrary file thumbnails, risking exposure of sensitive data

Affected Systems and Versions

Product: Electron, Vendor: Electron
Vulnerable Versions: < 11.5.0, >= 12.0.0, < 12.1.0, >= 13.0.0, < 13.3.0

Exploitation Mechanism

Sandbox renderers exploit the nativeImage API to request file thumbnails

Mitigation and Prevention

Explore ways to mitigate and prevent exploitation of this vulnerability.

Immediate Steps to Take

Upgrade Electron to fixed versions (15.0.0-alpha.10, 14.0.0, 13.3.0, 12.1.0, 11.5.0)
Enable

contextIsolation

in your app
Disable the

createThumbnailFromPath

API if not essential

Long-Term Security Practices

Regularly update Electron to latest versions
Implement sandboxing mechanisms in your applications

Patching and Updates

Stay informed about security patches and updates released by Electron.