CVE-2021-30612 – CVE-2021-30612 is a use-after-free vulnerabilit... (How to Fix)

Q: What is the severity of CVE-2021-30612?

CVE-2021-30612 has a CVSS score of 8.8 (HIGH). CVE-2021-30612 is a use-after-free vulnerability in WebRTC component of Chromium-based browsers. It allows remote attackers to execute arbitrary code or cause denial of service via crafted web content. Affects users of Chrome, Edge, and other Chromium-based browsers.

📋 TL;DR

CVE-2021-30612 is a use-after-free vulnerability in WebRTC component of Chromium-based browsers. It allows remote attackers to execute arbitrary code or cause denial of service via crafted web content. Affects users of Chrome, Edge, and other Chromium-based browsers.

💻 Affected Systems

Products:

Google Chrome
Microsoft Edge
Chromium-based browsers

Versions: Chrome versions before 93.0.4577.63, Edge versions before 93.0.961.38

Operating Systems: Windows, Linux, macOS, Android, iOS

Default Config Vulnerable: ⚠️ Yes

Notes: All default configurations with WebRTC enabled are vulnerable. WebRTC is enabled by default in most browsers.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution leading to complete system compromise, data theft, or ransomware deployment.

🟠

Likely Case

Browser crash/denial of service, potential information disclosure, or limited code execution in browser sandbox.

🟢

If Mitigated

Browser crash with no further impact if sandbox holds, or successful patch prevents exploitation.

🌐 Internet-Facing: HIGH - Exploitable via malicious websites or ads without user interaction beyond browsing.

🏢 Internal Only: MEDIUM - Requires user to visit malicious internal site or content, but internal threats exist.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Exploitation requires crafting malicious WebRTC content but no authentication. No public exploit code confirmed.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Chrome 93.0.4577.63, Edge 93.0.961.38

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

Restart Required: Yes

Instructions:

1. Open browser settings. 2. Navigate to 'About Chrome/Edge'. 3. Browser will automatically check for and apply updates. 4. Restart browser when prompted.

🔧 Temporary Workarounds

Disable WebRTC

all

Disable WebRTC functionality in browser settings or via extensions to prevent exploitation.

chrome://flags/#disable-webrtc (set to Enabled)
edge://flags/#disable-webrtc (set to Enabled)

Use browser extensions to block WebRTC

all

Install extensions like 'WebRTC Leak Prevent' or 'uBlock Origin' with WebRTC blocking enabled.

🧯 If You Can't Patch

Restrict browser usage to trusted websites only via network policies.
Implement application whitelisting to block unauthorized browser execution.

🔍 How to Verify

Check if Vulnerable:

Check browser version: Chrome: chrome://version, Edge: edge://version. If version is below 93.0.4577.63 (Chrome) or 93.0.961.38 (Edge), it's vulnerable.

Check Version:

chrome --version (Linux/macOS) or check via browser settings on Windows.

Verify Fix Applied:

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

📡 Detection & Monitoring

Log Indicators:

Browser crash logs with WebRTC-related modules
Unexpected browser process termination

Network Indicators:

Unusual WebRTC traffic patterns
Requests to known malicious domains hosting exploit

SIEM Query:

source="browser_logs" AND (event="crash" AND module="webrtc") OR (url="*malicious*" AND protocol="webrtc")

📊 Metadata

CVE ID: CVE-2021-30612

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

📤 Share & Export

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