CVE-2021-42850
📋 TL;DR
This vulnerability allows attackers with physical or local network access to gain unauthorized administrative access to Lenovo Personal Cloud Storage devices due to weak default passwords. Affected users are those who haven't changed default credentials on vulnerable Lenovo cloud storage devices.
💻 Affected Systems
- Lenovo Personal Cloud Storage devices
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of stored data, device takeover, lateral movement to connected systems, and persistent backdoor installation.
Likely Case
Unauthorized access to stored files, data theft, and potential ransomware deployment on the storage device.
If Mitigated
No impact if strong unique passwords are set and physical/network access is properly controlled.
🎯 Exploit Status
Exploitation requires guessing/default password use. No technical exploit code needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified in advisory
Vendor Advisory: https://iknow.lenovo.com.cn/detail/dc_200017.html
Restart Required: No
Instructions:
1. Access Lenovo advisory 2. Download latest firmware 3. Apply firmware update 4. Change all default passwords
🔧 Temporary Workarounds
Change Default Credentials
allImmediately change all default administrator passwords to strong, unique passwords
Network Segmentation
allIsolate device on separate VLAN with strict access controls
🧯 If You Can't Patch
- Change all default passwords immediately
- Restrict physical and network access to device
- Monitor for unauthorized access attempts
🔍 How to Verify
Check if Vulnerable:
Check if default administrator password is still in use on web interface or serial portCheck Version:
Check device web interface or serial console for firmware versionVerify Fix Applied:
Verify firmware version is updated and default passwords are changed📡 Detection & Monitoring
Log Indicators:
- Failed login attempts, successful logins from unknown IPs, configuration changes
Network Indicators:
- Unauthorized access to admin ports, unusual data transfer patterns
SIEM Query:
source="lenovo-cloud" AND (event_type="login" OR event_type="config_change")