CVE-2021-22727
📋 TL;DR
This vulnerability allows attackers to gain unauthorized access to Schneider Electric EVlink charging station web servers due to insufficient entropy in cryptographic operations. It affects EVlink City, EVlink Parking, and EVlink Smart Wallbox charging stations. Attackers could potentially take control of charging infrastructure.
💻 Affected Systems
- EVlink City (EVC1S22P4, EVC1S7P4)
- EVlink Parking (EVW2, EVF2, EV.2)
- EVlink Smart Wallbox (EVB1A)
📦 What is this software?
Evlink City Evc1s22p4 Firmware by Schneider Electric
Evlink City Evc1s7p4 Firmware by Schneider Electric
Evlink Parking Ev.2 Firmware by Schneider Electric
Evlink Parking Evf2 Firmware by Schneider Electric
Evlink Parking Evw2 Firmware by Schneider Electric
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of charging station allowing attackers to disable charging, manipulate billing, access connected networks, or cause physical damage through electrical manipulation.
Likely Case
Unauthorized access to web interface allowing configuration changes, data theft, or denial of service to charging functionality.
If Mitigated
Limited impact if stations are isolated on separate networks with strict firewall rules and access controls.
🎯 Exploit Status
CWE-331 vulnerabilities typically involve predictable cryptographic values that can be guessed or brute-forced.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: R8 V3.4.0.1
Vendor Advisory: http://download.schneider-electric.com/files?p_Doc_Ref=SEVD-2021-194-06
Restart Required: Yes
Instructions:
1. Download firmware R8 V3.4.0.1 from Schneider Electric portal. 2. Backup current configuration. 3. Upload firmware via web interface. 4. Reboot charging station. 5. Verify firmware version.
🔧 Temporary Workarounds
Network Isolation
allIsolate charging stations on separate VLAN with strict firewall rules blocking external access.
Access Control Lists
allImplement IP-based access restrictions to web interface allowing only authorized management systems.
🧯 If You Can't Patch
- Segment charging station network from critical infrastructure
- Implement strict firewall rules blocking all inbound traffic except from authorized management IPs
🔍 How to Verify
Check if Vulnerable:
Check firmware version via web interface or management console. If version is earlier than R8 V3.4.0.1, system is vulnerable.Check Version:
Access web interface and navigate to System Information or use Schneider Electric management tools.Verify Fix Applied:
Verify firmware version shows R8 V3.4.0.1 or later in web interface or management console.📡 Detection & Monitoring
Log Indicators:
- Failed authentication attempts
- Unauthorized configuration changes
- Unexpected firmware update attempts
Network Indicators:
- Unusual traffic patterns to charging station web ports
- External IPs accessing charging station interfaces
SIEM Query:
source="charging_station" AND (event_type="auth_failure" OR event_type="config_change")