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CVE-2021-2309

7.5 HIGH

📋 TL;DR

This vulnerability in Oracle VM VirtualBox allows a high-privileged attacker with local access to the host system to compromise the virtualization software, potentially leading to full takeover. It affects VirtualBox versions prior to 6.1.20. While difficult to exploit, successful attacks could impact other products running within the virtualized environment.

💻 Affected Systems

Products:
  • Oracle VM VirtualBox
Versions: All versions prior to 6.1.20
Operating Systems: All platforms running VirtualBox (Windows, Linux, macOS, Solaris)
Default Config Vulnerable: ⚠️ Yes
Notes: Affects all default installations of VirtualBox prior to 6.1.20. Component affected is the Core virtualization engine.

📦 What is this software?

Vm Virtualbox by Oracle

View all CVEs affecting Vm Virtualbox →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete compromise of Oracle VM VirtualBox allowing attacker to escape virtualization, access host system, and compromise all virtual machines running on the host.

🟠

Likely Case

Privileged attacker with existing host access gains elevated control over VirtualBox components, potentially affecting guest VM security and integrity.

🟢

If Mitigated

With proper access controls and patching, impact is limited to denial of service or minor privilege escalation within VirtualBox context.

🌐 Internet-Facing: LOW - Requires local access to host system, not directly exploitable over network.
🏢 Internal Only: MEDIUM - Requires high-privileged local access, but could be exploited by malicious insiders or compromised admin accounts.

🎯 Exploit Status

Public PoC: ✅ No
Weaponized: UNKNOWN
Unauthenticated Exploit: ✅ No
Complexity: HIGH

Exploitation requires high privileges (PR:H) and local access (AV:L), making it difficult to exploit. No public exploit code identified in references.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 6.1.20 or later

Vendor Advisory: https://www.oracle.com/security-alerts/cpuapr2021.html

Restart Required: Yes

Instructions:

1. Download VirtualBox 6.1.20 or later from Oracle website. 2. Stop all running VMs. 3. Uninstall current VirtualBox version. 4. Install updated version. 5. Restart host system if required.

🔧 Temporary Workarounds

Restrict Local Access

all

Limit local administrative access to VirtualBox hosts to trusted personnel only

Network Segmentation

all

Isolate VirtualBox hosts from critical network segments

🧯 If You Can't Patch

  • Implement strict access controls - only allow trusted administrators to access VirtualBox hosts
  • Monitor for suspicious activity on VirtualBox hosts and review logs regularly

🔍 How to Verify

Check if Vulnerable:

Check VirtualBox version: On Windows use 'VBoxManage --version', on Linux/macOS use 'VBoxManage --version' or check About dialog in GUI

Check Version:

VBoxManage --version

Verify Fix Applied:

Verify version is 6.1.20 or higher using same commands

📡 Detection & Monitoring

Log Indicators:

  • Unusual VirtualBox process activity
  • Unexpected VirtualBox service restarts
  • Failed authentication attempts on VirtualBox host

Network Indicators:

  • Unusual network traffic from VirtualBox host to internal systems

SIEM Query:

source="VirtualBox" AND (event_type="error" OR event_type="critical")

📊 Metadata

CVE ID: CVE-2021-2309
CVSS v3 Score: 7.5 (HIGH)
CVSS Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
Published: April 22, 2021
Last Updated: November 21, 2024

🔗 References

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