CVE-2022-3312 - How a ChromeOS VPN Flaw Let Attackers Bypass Device Management

Every day, millions of Chromebooks quietly help users around the world stay productive and safe. Businesses rely on device management to make sure users—and their data—stay protected. But sometimes, a single bug can put all of that at risk. CVE-2022-3312 is one of those bugs: a vulnerability in Google Chrome on ChromeOS that could let someone sitting in front of your device sneak past restrictions you thought were bulletproof.

In this exclusive post, we’ll dig into the technical details of CVE-2022-3312, see why “validating input” matters, and look at how local attackers could break out of managed configurations using VPN settings—plus, you’ll find code snippets and links to more info if you want to dig deeper.

What is CVE-2022-3312?

CVE-2022-3312 is a vulnerability found in the VPN component of Google Chrome running on ChromeOS. Before the patch in version 106..5249.62, ChromeOS failed to *sufficiently check* the data coming from untrusted sources when configuring VPN settings.

Severity: Medium
Exploitability: Local (physical access needed)
Impact: Allows a local attacker to bypass enforced restrictions on a managed (enterprise) Chromebook by manipulating VPN settings.

Official Summary

> *Insufficient validation of untrusted input in VPN in Google Chrome on ChromeOS prior to 106..5249.62 allowed a local attacker to bypass managed device restrictions via physical access to the device. (Chromium security severity: Medium)*
> — Chromium Security Advisories

Why Device Management Matters

In businesses and schools, ChromeOS devices are “managed” using stringent policies: admins can block websites, apps, and even set which networks a device is allowed to join. This keeps users focused and safe. If an attacker can bypass these, all bets are off—they might access blocked content, install rogue apps, or expose company data.

The Vulnerability: Where ChromeOS Slipped

In normal operation, when a VPN configuration is applied, ChromeOS should *always check* if the settings are safe and allowed—even if they come from the user, an extension, or even an attacker. But in versions *before 106..5249.62*, there was a gap:

An attacker with physical access could feed in crafted VPN setup data

This could allow a user (or someone who stole/borrowed a managed device) to use custom VPNs to sidestep network restrictions the admin had set up.

Code Snippet: Hypothetical Exploit Pathway

Note: The actual ChromeOS source for this is closed, but here’s a simplified (and *educational*) Python snippet that mimics how insufficient input validation could be abused.

def apply_vpn_config(user_input):
    # BAD: assumes user_input is always safe
    config = parse_json(user_input)
    # No check if config matches admin rules!
    vpn_manager.apply_config(config)

# Attacker's crafted input
evil_vpn = {
    "server": "evil-vpn.example.com",
    "bypass": True,
    "allow_insecure": True
}

apply_vpn_config(evil_vpn)

VPN Settings: Uses ChromeOS settings, or developer tools, to create a new VPN connection.

3. Crafted Input: Supplies a custom configuration that violates managed policies—maybe routing traffic to forbidden sites, or using a VPN the admin didn’t approve.
4. Bypassing Restrictions: Once connected, the device ignores admin-imposed blocks—attacker can browse, download, or exfiltrate data unnoticed.

Real-World Impact

For most home users, this vulnerability isn’t a big problem—you (or anyone who borrows your device) can already change VPN settings. The real risk is where devices *must* obey admin policies: schools, corporations, governments.

Data leaks: A user could access company resources behind firewalls or leak data outside.

- Policy dodge: Malicious insiders (or thieves) could operate these devices as if nobody’s watching.
- Regulatory risk: Sensitive organizations, like hospitals or banks, could accidentally fall out of compliance.

Update your devices!

- ChromeOS Releases Blog – September 2022
- Full list of Chrome Stable changes

CVE-2022-3312 let local attackers on ChromeOS use VPNs to break out of admin controls.

- The risk only affected managed (enterprise/school) devices prior to version 106..5249.62.

Timeline

Published on: 11/01/2022 20:15:00 UTC
Last modified on: 12/08/2022 21:39:00 UTC