CVE-2023-27857
📋 TL;DR
This vulnerability in Rockwell Automation's ThinManager ThinServer allows unauthenticated remote attackers to trigger a heap-based buffer over-read by sending specially crafted messages. Exploitation causes ThinServer.exe to crash due to a read access violation, resulting in denial of service. All systems running affected versions of ThinManager ThinServer are vulnerable.
💻 Affected Systems
- Rockwell Automation ThinManager ThinServer
📦 What is this software?
Thinmanager by Rockwellautomation
Thinmanager by Rockwellautomation
Thinmanager by Rockwellautomation
Thinmanager by Rockwellautomation
Thinmanager by Rockwellautomation
Thinmanager by Rockwellautomation
⚠️ Risk & Real-World Impact
Worst Case
Complete denial of service of ThinServer, disrupting industrial operations that depend on this software for HMI/SCADA functionality.
Likely Case
Service disruption and potential downtime in industrial environments until the service can be restarted.
If Mitigated
Minimal impact if systems are properly segmented and not exposed to untrusted networks.
🎯 Exploit Status
The vulnerability is unauthenticated and involves sending malformed messages, making exploitation relatively straightforward.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version 11.2.0 or later
Vendor Advisory: https://rockwellautomation.custhelp.com/app/answers/answer_view/a_id/1138640
Restart Required: Yes
Instructions:
1. Download ThinManager version 11.2.0 or later from Rockwell Automation. 2. Backup current configuration. 3. Install the updated version. 4. Restart the ThinServer service.
🔧 Temporary Workarounds
Network Segmentation
allIsolate ThinServer systems from untrusted networks using firewalls or network segmentation.
Access Control Lists
allImplement strict network access controls to limit which systems can communicate with ThinServer.
🧯 If You Can't Patch
- Implement strict network segmentation to isolate ThinServer from all untrusted networks
- Deploy intrusion detection/prevention systems to monitor for exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check ThinManager version in the application interface or Windows Programs and Features. Versions below 11.2.0 are vulnerable.Check Version:
Check ThinManager application interface or Windows Control Panel > Programs and FeaturesVerify Fix Applied:
Verify ThinManager version is 11.2.0 or higher after patching and ensure ThinServer service is running normally.📡 Detection & Monitoring
Log Indicators:
- ThinServer.exe crash events in Windows Event Logs
- Unexpected service termination
Network Indicators:
- Unusual traffic patterns to ThinServer port (default 2031/TCP)
- Malformed packets targeting ThinServer
SIEM Query:
EventID: 1000 OR EventID: 1001 Source: ThinServer.exe OR Process: ThinServer.exe