CVE-2022-26723
📋 TL;DR
This is a critical memory corruption vulnerability in macOS Samba client that allows arbitrary code execution when mounting a malicious Samba network share. Attackers can exploit this to gain full control of affected systems. All macOS users who mount Samba shares are potentially affected.
💻 Affected Systems
- macOS
📦 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...
Learn more about Macos →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...
Learn more about Macos →⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with root privileges, data theft, ransomware deployment, and persistent backdoor installation.
Likely Case
Local privilege escalation leading to full system control, data exfiltration, and lateral movement within the network.
If Mitigated
Limited impact if systems are isolated, have strict network controls, and users don't mount untrusted Samba shares.
🎯 Exploit Status
Exploitation requires the victim to mount a malicious Samba share, which could be achieved through social engineering or network attacks.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: macOS Monterey 12.4, macOS Big Sur 11.6.6
Vendor Advisory: https://support.apple.com/en-us/HT213256
Restart Required: Yes
Instructions:
1. Open System Preferences > Software Update. 2. Install macOS Monterey 12.4 or macOS Big Sur 11.6.6 update. 3. Restart the system when prompted.
🔧 Temporary Workarounds
Disable Samba client mounting
allPrevent mounting of Samba network shares to block exploitation vectors
sudo defaults write /Library/Preferences/com.apple.AppleFileServer guestAccess -bool false
sudo defaults write /Library/Preferences/SystemConfiguration/com.apple.smb.server AllowGuestAccess -bool false
Network segmentation
allIsolate systems from untrusted Samba servers using firewall rules
sudo pfctl -f /etc/pf.conf
Add rules to block SMB ports (139, 445) from untrusted networks
🧯 If You Can't Patch
- Implement strict network controls to prevent connections to untrusted Samba servers
- Educate users about the risks of mounting untrusted network shares and implement approval processes
🔍 How to Verify
Check if Vulnerable:
Check macOS version: System Preferences > About This Mac. If version is Monterey < 12.4 or Big Sur < 11.6.6, system is vulnerable.Check Version:
sw_versVerify Fix Applied:
Verify macOS version is 12.4 or higher for Monterey, or 11.6.6 or higher for Big Sur.📡 Detection & Monitoring
Log Indicators:
- Unexpected Samba mount attempts in system logs
- Process execution from mounted network shares
- Network connections to unknown SMB servers
Network Indicators:
- SMB traffic to/from untrusted IP addresses
- Unusual SMB protocol patterns
- Multiple failed mount attempts
SIEM Query:
source="macos_system_logs" AND (event="mount" OR event="smb") AND dest_ip NOT IN [trusted_ips]