CVE-2020-27744
📋 TL;DR
CVE-2020-27744 is a critical remote code execution vulnerability affecting Western Digital My Cloud NAS devices. It allows attackers to execute arbitrary commands with root privileges on vulnerable devices. This affects all Western Digital My Cloud NAS devices running firmware versions before 5.04.114.
💻 Affected Systems
- Western Digital My Cloud NAS devices
📦 What is this software?
My Cloud Firmware by Westerndigital
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the NAS device with root access, allowing data theft, ransomware deployment, and use as a pivot point into internal networks.
Likely Case
Remote attackers gaining full control of the NAS, accessing all stored data, and potentially using the device for further attacks.
If Mitigated
Limited impact if device is isolated from internet and strict network segmentation is in place.
🎯 Exploit Status
Exploitation requires no authentication and has been weaponized in real attacks.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 5.04.114
Vendor Advisory: https://www.westerndigital.com/support/productsecurity/wdc-20007-my-cloud-firmware-version-5-04-114
Restart Required: Yes
Instructions:
1. Log into My Cloud web interface. 2. Navigate to Settings > Firmware. 3. Check for updates and install version 5.04.114 or later. 4. Reboot the device after installation.
🔧 Temporary Workarounds
Network Isolation
allRemove device from internet exposure by placing behind firewall with no inbound internet access.
Access Restriction
allRestrict network access to trusted IP addresses only using firewall rules.
🧯 If You Can't Patch
- Immediately disconnect device from internet and isolate on separate VLAN
- Disable all remote access features and disable UPnP on router
🔍 How to Verify
Check if Vulnerable:
Check firmware version in My Cloud web interface under Settings > Firmware. If version is below 5.04.114, device is vulnerable.Check Version:
Not applicable - version check through web interface onlyVerify Fix Applied:
Confirm firmware version shows 5.04.114 or higher in Settings > Firmware.📡 Detection & Monitoring
Log Indicators:
- Unusual command execution in system logs
- Unauthorized access attempts to administrative interfaces
- Unexpected process creation
Network Indicators:
- Unusual outbound connections from NAS device
- Exploit traffic patterns to port 80/443
- Command and control beaconing
SIEM Query:
source="mycloud" AND (event="command_execution" OR event="unauthorized_access")🔗 References
- https://www.comparitech.com/blog/information-security/security-vulnerabilities-80000-devices-update-now/
- https://www.westerndigital.com/support/productsecurity/wdc-20007-my-cloud-firmware-version-5-04-114
- https://www.comparitech.com/blog/information-security/security-vulnerabilities-80000-devices-update-now/
- https://www.westerndigital.com/support/productsecurity/wdc-20007-my-cloud-firmware-version-5-04-114
