CVE-2021-27410
📋 TL;DR
This critical vulnerability allows attackers to write data beyond intended memory boundaries in Welch Allyn medical device management tools, potentially leading to remote code execution or system corruption. It affects multiple Welch Allyn medical devices and management software versions. Healthcare organizations using these devices are at risk.
💻 Affected Systems
- Welch Allyn Service Tool
- Welch Allyn Connex Device Integration Suite - Network Connectivity Engine (NCE)
- Welch Allyn Software Development Kit (SDK)
- Welch Allyn Connex Central Station (CS)
- Welch Allyn Service Monitor
- Welch Allyn Connex Vital Signs Monitor (CVSM)
- Welch Allyn Connex Integrated Wall System (CIWS)
- Welch Allyn Connex Spot Monitor (CSM)
- Welch Allyn Spot Vital Signs 4400 Device
- Welch Allyn Spot 4400 Vital Signs Extended Care Device
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote unauthenticated attacker gains full control of medical devices, potentially compromising patient safety by manipulating device functionality or accessing sensitive health data.
Likely Case
Attacker exploits the vulnerability to execute arbitrary code, disrupt medical device operations, or exfiltrate patient data from connected systems.
If Mitigated
With proper network segmentation and access controls, impact is limited to isolated medical device networks without affecting critical healthcare systems.
🎯 Exploit Status
CVSS 9.8 indicates critical severity with low attack complexity. No authentication required for exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v1.10 (Service Tool), v5.3 (NCE), v3.2 (SDK), v1.8.6 (CS), v1.7.0.0 (Service Monitor), v2.43.02 (CVSM/CIWS), v1.52 (CSM), v1.11.00 (Spot 4400)
Vendor Advisory: https://us-cert.cisa.gov/ics/advisories/icsma-21-152-01
Restart Required: Yes
Instructions:
1. Contact Welch Allyn for updated firmware/software. 2. Schedule maintenance window for medical devices. 3. Apply patches according to vendor instructions. 4. Restart affected devices. 5. Verify patch installation.
🔧 Temporary Workarounds
Network Segmentation
allIsolate medical devices on separate VLANs with strict firewall rules
Access Control
allImplement strict network access controls to limit connections to medical devices
🧯 If You Can't Patch
- Segment medical device networks from general hospital networks
- Implement strict firewall rules to block unnecessary inbound connections to medical devices
🔍 How to Verify
Check if Vulnerable:
Check device firmware/software version against affected versions listCheck Version:
Check device settings or management interface for version informationVerify Fix Applied:
Verify installed version matches or exceeds patched versions listed in fix_official.patch_version📡 Detection & Monitoring
Log Indicators:
- Unexpected device restarts
- Unusual network connections to medical devices
- Device error messages
Network Indicators:
- Unusual traffic patterns to/from medical device IPs
- Attempts to access device management ports
SIEM Query:
source_ip IN (medical_device_ips) AND (port=management_port OR protocol=unusual)