CVE-2018-3877
📋 TL;DR
A buffer overflow vulnerability in Samsung SmartThings Hub allows remote code execution by sending specially crafted HTTP requests. Attackers can exploit this to take control of affected devices. This affects Samsung SmartThings Hub STH-ETH-250 devices with vulnerable firmware.
💻 Affected Systems
- Samsung SmartThings Hub STH-ETH-250
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise leading to full control of the SmartThings Hub, potential access to connected IoT devices, and lateral movement within the network.
Likely Case
Remote code execution allowing attackers to install malware, create persistent access, or use the device as a pivot point for further attacks.
If Mitigated
Limited impact if device is isolated from untrusted networks and proper network segmentation is implemented.
🎯 Exploit Status
The vulnerability is well-documented with proof-of-concept available. Exploitation requires sending a specially crafted HTTP request with an overly long 'directory' parameter.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Later firmware versions (check Samsung SmartThings support for specific version)
Vendor Advisory: https://www.samsung.com/us/support/answer/ANS00078017/
Restart Required: Yes
Instructions:
1. Log into SmartThings app. 2. Navigate to Settings > Hub Information. 3. Check for firmware updates. 4. Apply available updates. 5. Reboot the hub after update completes.
🔧 Temporary Workarounds
Network Isolation
allIsolate SmartThings Hub from untrusted networks and restrict inbound access
Firewall Rules
linuxBlock external access to the SmartThings Hub HTTP server (typically port 39500)
iptables -A INPUT -p tcp --dport 39500 -j DROP
🧯 If You Can't Patch
- Segment the SmartThings Hub on a dedicated VLAN isolated from critical systems
- Implement strict network access controls to limit which devices can communicate with the hub
🔍 How to Verify
Check if Vulnerable:
Check firmware version in SmartThings app: Settings > Hub Information > Firmware version. If version is 0.20.17, device is vulnerable.Check Version:
Not applicable - version check through SmartThings mobile app interface onlyVerify Fix Applied:
Verify firmware version has been updated to a version later than 0.20.17 in the SmartThings app.📡 Detection & Monitoring
Log Indicators:
- Unusually long HTTP requests to /video/credentials endpoint
- Multiple failed authentication attempts with malformed directory parameters
Network Indicators:
- HTTP POST requests to port 39500 with directory parameter exceeding 160 characters
- Unusual outbound connections from SmartThings Hub
SIEM Query:
source="smartthings-hub" AND (http_uri="/video/credentials" AND http_param_length>160)