CVE-2017-7689
📋 TL;DR
CVE-2017-7689 is a command injection vulnerability in Schneider Electric homeLYnk Controller that allows attackers to execute arbitrary commands on the device. This affects all versions before 1.5.0, potentially compromising home automation systems.
💻 Affected Systems
- Schneider Electric homeLYnk Controller
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to execute arbitrary commands, potentially gaining full control of the homeLYnk Controller and connected home automation devices.
Likely Case
Attackers could manipulate home automation systems, disable security features, or use the device as a foothold for further network attacks.
If Mitigated
With proper network segmentation and access controls, impact would be limited to the isolated home automation network segment.
🎯 Exploit Status
Command injection vulnerabilities are typically easy to exploit once the attack vector is identified.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.5.0 or later
Vendor Advisory: http://download.schneider-electric.com/files?p_Doc_Ref=SEVD-2017-052-02
Restart Required: Yes
Instructions:
1. Download firmware version 1.5.0 or later from Schneider Electric support portal. 2. Log into homeLYnk Controller web interface. 3. Navigate to System > Firmware Update. 4. Upload and install the new firmware. 5. Reboot the device after installation completes.
🔧 Temporary Workarounds
Network Isolation
allIsolate homeLYnk Controller from internet and restrict network access to trusted devices only.
Access Control Lists
allImplement firewall rules to restrict access to homeLYnk Controller management interface.
🧯 If You Can't Patch
- Remove internet-facing access and place behind firewall with strict access controls
- Monitor network traffic to/from the device for suspicious command execution patterns
🔍 How to Verify
Check if Vulnerable:
Check firmware version in homeLYnk Controller web interface under System > About. If version is below 1.5.0, the device is vulnerable.Check Version:
Not applicable - version check is performed via web interfaceVerify Fix Applied:
After updating, verify firmware version shows 1.5.0 or higher in System > About section.📡 Detection & Monitoring
Log Indicators:
- Unusual command execution patterns in system logs
- Multiple failed login attempts followed by command execution
Network Indicators:
- Unusual outbound connections from homeLYnk Controller
- Suspicious HTTP requests to management interface
SIEM Query:
source="homeLYnk" AND (command="*;*" OR command="*|*" OR command="*`*" OR command="*$(*")🔗 References
- http://download.schneider-electric.com/files?p_Doc_Ref=SEVD-2017-052-02
- http://www.securityfocus.com/bid/97585
- https://ics-cert.us-cert.gov/advisories/ICSA-17-019-01A
- http://download.schneider-electric.com/files?p_Doc_Ref=SEVD-2017-052-02
- http://www.securityfocus.com/bid/97585
- https://ics-cert.us-cert.gov/advisories/ICSA-17-019-01A
