CVE-2019-6553
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on Rockwell Automation RSLinx Classic systems by exploiting a stack-based buffer overflow in a Forward Open service request. It affects industrial control systems using RSLinx Classic versions 4.10.00 and prior. Attackers can potentially take full control of affected systems.
💻 Affected Systems
- Rockwell Automation RSLinx Classic
📦 What is this software?
Rslinx by Rockwellautomation
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise leading to disruption of industrial processes, data theft, or physical damage to connected equipment
Likely Case
Remote code execution allowing attackers to install malware, pivot to other systems, or disrupt industrial operations
If Mitigated
Limited impact with proper network segmentation and access controls preventing exploitation attempts
🎯 Exploit Status
Buffer overflow in Forward Open service makes exploitation relatively straightforward for skilled attackers
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.11.00 and later
Vendor Advisory: https://rockwellautomation.custhelp.com/app/answers/detail/a_id/1086945
Restart Required: Yes
Instructions:
1. Download RSLinx Classic version 4.11.00 or later from Rockwell Automation website. 2. Backup current configuration. 3. Install the updated version. 4. Restart the system. 5. Verify installation and functionality.
🔧 Temporary Workarounds
Network Segmentation
allIsolate RSLinx Classic systems from untrusted networks using firewalls
Access Control Lists
windowsRestrict network access to RSLinx Classic ports (44818/TCP by default)
netsh advfirewall firewall add rule name="Block RSLinx" dir=in action=block protocol=TCP localport=44818
🧯 If You Can't Patch
- Implement strict network segmentation to isolate RSLinx systems from untrusted networks
- Deploy intrusion detection systems to monitor for exploitation attempts on port 44818/TCP
🔍 How to Verify
Check if Vulnerable:
Check RSLinx Classic version via Help > About in the application or check installed programs in WindowsCheck Version:
wmic product where "name like 'RSLinx%'" get versionVerify Fix Applied:
Verify version is 4.11.00 or later and test Forward Open service functionality📡 Detection & Monitoring
Log Indicators:
- Multiple failed Forward Open requests
- Unusual process creation from RSLinx executable
- Crash logs from RSLinx process
Network Indicators:
- Malformed packets to port 44818/TCP
- Unusual traffic patterns to RSLinx systems
- Exploit kit signatures targeting CVE-2019-6553
SIEM Query:
source="*rslinx*" AND (event_type="crash" OR "buffer overflow") OR destination_port=44818 AND packet_size>normal