CVE-2021-32971
📋 TL;DR
A null pointer dereference vulnerability in the SuiteLink server allows attackers to cause denial of service by sending a specially crafted command 0x07. This affects industrial control systems using vulnerable versions of AVEVA's SuiteLink server software, potentially disrupting critical operations.
💻 Affected Systems
- AVEVA SuiteLink Server
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete denial of service causing SuiteLink server crash, disrupting industrial control system communications and potentially halting operations.
Likely Case
Service disruption requiring server restart, causing temporary loss of connectivity between industrial control system components.
If Mitigated
Limited impact with proper network segmentation and monitoring allowing quick detection and recovery.
🎯 Exploit Status
Exploitation requires sending malformed command 0x07 to the SuiteLink server port (typically 1211/TCP). No authentication required.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.0.0.0 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 SuiteLink Server version 4.0.0.0 or later from AVEVA support portal. 2. Stop the SuiteLink service. 3. Install the updated version. 4. Restart the service.
🔧 Temporary Workarounds
Network Segmentation
allRestrict access to SuiteLink server port (1211/TCP) to only trusted industrial control system components.
firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="TRUSTED_IP_RANGE" port protocol="tcp" port="1211" accept'
netsh advfirewall firewall add rule name="SuiteLink Restrict" dir=in action=allow protocol=TCP localport=1211 remoteip=TRUSTED_IP_RANGE
🧯 If You Can't Patch
- Implement strict network segmentation to isolate SuiteLink servers from untrusted networks
- Deploy network monitoring and intrusion detection for traffic on port 1211/TCP
🔍 How to Verify
Check if Vulnerable:
Check SuiteLink Server version via Windows Programs and Features or by examining installed software version. Versions below 4.0.0.0 are vulnerable.Check Version:
wmic product where name="AVEVA SuiteLink Server" get versionVerify Fix Applied:
Confirm SuiteLink Server version is 4.0.0.0 or higher and verify service is running normally after patch.📡 Detection & Monitoring
Log Indicators:
- SuiteLink service crash events in Windows Event Log
- Unexpected service restarts
Network Indicators:
- Traffic to port 1211/TCP containing command 0x07 from untrusted sources
- Sudden cessation of normal SuiteLink communications
SIEM Query:
source="windows" AND (event_id=7034 OR event_id=1000) AND process_name="SuiteLink*"