CVE-2021-42852
📋 TL;DR
This CVE describes an authenticated command injection vulnerability in Lenovo Personal Cloud Storage devices that allows authenticated users to execute arbitrary operating system commands by sending specially crafted packets. The vulnerability affects users of specific Lenovo cloud storage products who have network access to these devices.
💻 Affected Systems
- Lenovo Personal Cloud Storage devices
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the device allowing attackers to execute arbitrary commands with device privileges, potentially leading to data theft, device takeover, or lateral movement within the network.
Likely Case
Authenticated attackers gaining shell access to execute commands, potentially compromising stored data and using the device as a foothold for further attacks.
If Mitigated
Limited impact due to authentication requirement and network segmentation, with attackers only able to affect the specific vulnerable device.
🎯 Exploit Status
Exploitation requires authenticated access but command injection is typically straightforward once access is obtained
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified in public advisory
Vendor Advisory: https://iknow.lenovo.com.cn/detail/dc_200017.html
Restart Required: Yes
Instructions:
1. Check Lenovo advisory for specific firmware updates
2. Download latest firmware from Lenovo support site
3. Apply firmware update through device web interface
4. Reboot device after update completion
🔧 Temporary Workarounds
Network Segmentation
allIsolate Lenovo Personal Cloud Storage devices from untrusted networks and limit access to authorized users only
Access Control
allImplement strict authentication controls and limit administrative access to trusted users only
🧯 If You Can't Patch
- Remove internet-facing exposure by placing devices behind VPN or firewall with strict access controls
- Implement network monitoring for unusual command execution patterns and restrict device to internal network only
🔍 How to Verify
Check if Vulnerable:
Check device firmware version against Lenovo's advisory and verify if device model is listed as affectedCheck Version:
Check device web interface under System Information or Settings for firmware versionVerify Fix Applied:
Verify firmware has been updated to latest version and test that command injection attempts are properly sanitized📡 Detection & Monitoring
Log Indicators:
- Unusual command execution patterns in device logs
- Multiple failed authentication attempts followed by successful login
Network Indicators:
- Unusual outbound connections from device
- Suspicious packets to device management interface
SIEM Query:
source="lenovo-cloud-storage" AND (event="command_execution" OR event="shell_access")