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CVE-2020-27903

7.8 HIGH

📋 TL;DR

CVE-2020-27903 is a privilege escalation vulnerability in macOS that allows an application to gain elevated privileges. This affects macOS systems prior to Big Sur 11.0.1, potentially enabling malicious software to execute with higher permissions than intended.

💻 Affected Systems

Products:
  • macOS
Versions: Versions prior to macOS Big Sur 11.0.1
Operating Systems: macOS
Default Config Vulnerable: ⚠️ Yes
Notes: All default macOS installations running vulnerable versions are affected. The vulnerability was in the operating system itself.

📦 What is this software?

Macos by Apple

macOS is Apple's desktop and laptop operating system powering Mac computers used by millions of professionals, developers, creative professionals, and enterprise users worldwide. Built on a Unix foundation with the Darwin kernel and modern Cocoa frameworks, macOS delivers a seamless ecosystem integr...

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⚠️ Risk & Real-World Impact

🔴

Worst Case

An attacker could gain root-level access to the system, allowing complete compromise, data theft, persistence installation, and lateral movement.

🟠

Likely Case

Malicious applications could bypass sandbox restrictions and gain elevated privileges to access protected system resources or user data.

🟢

If Mitigated

With proper application sandboxing and least privilege principles, impact would be limited to the specific application's context.

🌐 Internet-Facing: LOW - This requires local application execution, not directly exploitable over the network.
🏢 Internal Only: HIGH - Local attackers or malware could exploit this to escalate privileges on compromised macOS systems.

🎯 Exploit Status

Public PoC: ⚠️ Yes
Weaponized: LIKELY
Unauthenticated Exploit: ✅ No
Complexity: MEDIUM

Exploitation requires an attacker to have local access or trick a user into running a malicious application. Public disclosures suggest exploit details are available.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: macOS Big Sur 11.0.1

Vendor Advisory: https://support.apple.com/en-us/HT211931

Restart Required: Yes

Instructions:

1. Open System Preferences > Software Update. 2. Install macOS Big Sur 11.0.1 or later. 3. Restart the system when prompted.

🔧 Temporary Workarounds

Application Sandboxing Enforcement

all

Enforce strict application sandboxing policies to limit potential damage from malicious applications.

Restrict Application Installation

all

Only allow installation of applications from trusted sources (App Store or identified developers).

🧯 If You Can't Patch

  • Implement strict application control policies to prevent unauthorized software execution
  • Use endpoint detection and response (EDR) solutions to monitor for privilege escalation attempts

🔍 How to Verify

Check if Vulnerable:

Check macOS version: if running version prior to 11.0.1, system is vulnerable.

Check Version:

sw_vers

Verify Fix Applied:

Verify macOS version is 11.0.1 or later after update.

📡 Detection & Monitoring

Log Indicators:

  • Unexpected privilege escalation events in system logs
  • Applications running with unexpected privileges

Network Indicators:

  • Not applicable - local privilege escalation

SIEM Query:

source="macos_system_logs" AND (event="privilege_escalation" OR process_elevation="true")

📊 Metadata

CVE ID: CVE-2020-27903
CVSS v3 Score: 7.8 (HIGH)
CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Published: December 8, 2020
Last Updated: November 21, 2024

🔗 References

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