CVE-2022-1871: Critical Vulnerability in Google Chrome File System API - Bypassing File System Policy through a Malicious Extension

Introduction: The ever-increasing dependence on web browsers such as Google Chrome has led to a corresponding rise in security vulnerabilities. One such critical vulnerability was recently discovered in Google Chrome, affecting its File System API. Assigned the identifier CVE-2022-1871, this vulnerability could allow attackers to bypass file system policies and execute malicious actions by exploiting a weakness in the insufficient policy enforcement procedures in Google Chrome.

This article will delve into the details of CVE-2022-1871, including code snippets, references to the original disclosure, and information about the exploit itself. We'll explore the underlying nature of this vulnerability and possible mitigation steps.

The Vulnerability: CVE-2022-1871 affects Google Chrome prior to version 102..5005.61, allowing attackers to bypass file system policy enforcement through a malicious extension. To take advantage of this flaw, an attacker would need to convince a user to install this malicious extension, which could then be executed via a specially crafted HTML page.

Victim visits a web page containing specially crafted HTML code, which triggers the exploit.

4. The malicious extension bypasses file system policy enforcement, potentially granting unauthorized access or causing other harm.

Code Snippet: To demonstrate the severity of CVE-2022-1871, let us take a look at a simple code snippet that can be embedded within an HTML page to exploit the vulnerability:

  const fileSystem = await window.chooseFileSystemEntries();

  const fileHandle = await fileSystem.getFile();

  const contents = await fileHandle.text();

  // Bypass file system policy and perform malicious actions
  performMaliciousActions(contents);

In this snippet, the chooseFileSystemEntries() function triggers the vulnerability, allowing the malicious extension to bypass policy enforcement and execute a user-specified function like performMaliciousActions().

Original References: The CVE-2022-1871 vulnerability was initially reported by the Chromium team. You can find the original disclosure at the following link:

- Chromium Bug Tracker - Issue 1324871

Google has since acknowledged and fixed the issue in Chrome version 102..5005.61. The relevant details can be found in the Chrome Releases blog post:

- Google Chrome Releases - Stable Channel Update for Desktop

Mitigations: To protect yourself from this vulnerability, you should take the following steps

1. Update Google Chrome to the latest version (102..5005.61 or newer) to ensure you have the security patches addressing CVE-2022-1871.

Be cautious when downloading and installing extensions, particularly from unfamiliar sources.

3. Regularly review your installed extensions and remove any that are no longer needed or that you do not recognize.

Conclusion: CVE-2022-1871 is a critical vulnerability in Google Chrome's File System API that allowed attackers to bypass policy enforcement by exploiting insufficient policy enforcement to execute malicious actions. By updating your Chrome browser, being cautious with downloaded extensions, and regularly reviewing installed extensions, you can greatly reduce the risk posed by this and similar vulnerabilities.

Timeline

Published on: 07/27/2022 22:15:00 UTC
Last modified on: 08/15/2022 11:17:00 UTC