CVE-2021-32987
📋 TL;DR
A null pointer dereference vulnerability in the SuiteLink server allows attackers to crash the service by sending a specially crafted command 0x0b. This affects industrial control systems using AVEVA's SuiteLink protocol for data exchange. The vulnerability can cause denial of service in critical industrial environments.
💻 Affected Systems
- AVEVA InTouch HMI
- AVEVA System Platform
- AVEVA Edge
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete denial of service of SuiteLink server, disrupting industrial control system communications and potentially causing process shutdowns or safety incidents in critical infrastructure.
Likely Case
Service crash requiring manual restart, causing temporary disruption to industrial data exchange and monitoring capabilities.
If Mitigated
Minimal impact with proper network segmentation and monitoring; service can be quickly restored from backup configurations.
🎯 Exploit Status
Exploitation requires sending a single malformed packet to port 4000/TCP. No authentication required if network access is available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2020 R2 SP1 and later
Vendor Advisory: https://www.aveva.com/content/dam/aveva/documents/support/cyber-security-updates/SecurityBulletin_AVEVA-2021-003.pdf
Restart Required: Yes
Instructions:
1. Download and install AVEVA 2020 R2 SP1 or later from AVEVA support portal. 2. Apply the update to all affected systems. 3. Restart the SuiteLink service or reboot the system.
🔧 Temporary Workarounds
Network Segmentation
allRestrict access to SuiteLink server port 4000/TCP using firewalls or network segmentation.
# Windows Firewall: netsh advfirewall firewall add rule name="Block SuiteLink" dir=in action=block protocol=TCP localport=4000
# Linux iptables: iptables -A INPUT -p tcp --dport 4000 -j DROP
Service Disablement
windowsDisable SuiteLink server if not required for operations.
# Windows: sc stop "SuiteLink Server" && sc config "SuiteLink Server" start= disabled
🧯 If You Can't Patch
- Implement strict network segmentation to isolate SuiteLink servers from untrusted networks.
- Deploy intrusion detection systems to monitor for exploitation attempts on port 4000/TCP.
🔍 How to Verify
Check if Vulnerable:
Check AVEVA software version. If version is earlier than 2020 R2 SP1 and SuiteLink server is running, the system is vulnerable.Check Version:
# Check AVEVA version in Windows: wmic product where "name like '%AVEVA%'" get name,versionVerify Fix Applied:
Verify installed version is 2020 R2 SP1 or later and test SuiteLink connectivity remains functional.📡 Detection & Monitoring
Log Indicators:
- SuiteLink service crash events in Windows Event Log
- Unexpected restarts of AVEVA services
Network Indicators:
- TCP connections to port 4000 followed by service termination
- Malformed packets to port 4000 containing command 0x0b
SIEM Query:
source="windows" AND (event_id=7034 OR event_id=1000) AND process_name="*SuiteLink*"