CVE-2021-30622 – This vulnerability is a use-after-free flaw in ... (How to Fix)

Q: What is the severity of CVE-2021-30622?

CVE-2021-30622 has a CVSS score of 8.8 (HIGH). This vulnerability is a use-after-free flaw in Chromium's WebApp installation component that allows attackers to execute arbitrary code or cause a denial of service. It affects all Chromium-based browsers including Google Chrome, Microsoft Edge, and other derivatives. Attackers can exploit this by tricking users into visiting malicious websites.

📋 TL;DR

This vulnerability is a use-after-free flaw in Chromium's WebApp installation component that allows attackers to execute arbitrary code or cause a denial of service. It affects all Chromium-based browsers including Google Chrome, Microsoft Edge, and other derivatives. Attackers can exploit this by tricking users into visiting malicious websites.

💻 Affected Systems

Products:

Google Chrome
Microsoft Edge
Chromium-based browsers

Versions: Chromium versions before 93.0.4577.63

Operating Systems: Windows, Linux, macOS, Android

Default Config Vulnerable: ⚠️ Yes

Notes: All standard installations are vulnerable. The vulnerability is in the Chromium engine, so any browser using affected Chromium versions is impacted.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution with the privileges of the browser process, potentially leading to full system compromise if combined with other vulnerabilities or running with elevated privileges.

🟠

Likely Case

Browser crash (denial of service) or limited code execution within the browser sandbox, potentially enabling further exploitation through chained vulnerabilities.

🟢

If Mitigated

Browser crash with no data loss if sandboxing works properly, though user may lose unsaved work.

🌐 Internet-Facing: HIGH - Exploitation requires only visiting a malicious website, which is common for browser-based attacks.

🏢 Internal Only: MEDIUM - Internal users could be targeted via phishing or compromised internal websites, but requires user interaction.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Exploitation requires user interaction (visiting malicious site) but no authentication. Use-after-free vulnerabilities typically require precise timing and memory manipulation.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Chrome 93.0.4577.63 and later, Edge 93.0.961.38 and later

Vendor Advisory: https://chromereleases.googleblog.com/2021/08/stable-channel-update-for-desktop_31.html

Restart Required: Yes

Instructions:

1. Open Chrome/Edge browser. 2. Click menu (three dots) → Help → About Google Chrome/About Microsoft Edge. 3. Browser will automatically check for updates and install if available. 4. Click 'Relaunch' to restart browser with updated version.

🔧 Temporary Workarounds

Disable WebApp Installation

all

Prevent WebApp installation functionality which contains the vulnerable component

Not applicable - configure via browser policies or flags

Enable Site Isolation

all

Ensure site isolation is enabled to limit impact of potential exploitation

chrome://flags/#site-isolation-trial-opt-out → Set to 'Disabled'

🧯 If You Can't Patch

Use alternative browsers not based on affected Chromium versions
Implement web filtering to block known malicious sites and restrict browser usage to trusted domains only

🔍 How to Verify

Check if Vulnerable:

Check browser version: Chrome/Edge → Menu → Help → About. If version is below 93.0.4577.63 (Chrome) or 93.0.961.38 (Edge), you are vulnerable.

Check Version:

On Windows: "reg query "HKEY_CURRENT_USER\Software\Google\Chrome\BLBeacon" /v version" or check browser About page

Verify Fix Applied:

Confirm browser version is 93.0.4577.63 or higher for Chrome, or 93.0.961.38 or higher for Edge.

📡 Detection & Monitoring

Log Indicators:

Browser crash reports with memory access violations
Unexpected browser process termination
WebApp installation failures

Network Indicators:

Connections to suspicious domains followed by browser crashes
Multiple rapid requests to WebApp installation endpoints

SIEM Query:

source="browser_crash_logs" AND (event_id="1000" OR event_id="1001") AND process_name="chrome.exe" AND memory_address_violation

📊 Metadata

CVE ID: CVE-2021-30622

CVSS v3 Score: 8.8 (HIGH)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CWE: CWE-416

Published: September 3, 2021

Last Updated: November 21, 2024

🔗 References

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