CVE-2026-20744: Hydro-Québec Le Circuit Electrique Backend — Detection and Hardening Guide

---
title: Hydro-Québec Backend Potential WebSocket Auth Bypass
id: 8c4d5f12-1a3b-4f2c-9e0d-7b6a5c4d3e2f
status: experimental
description: Detects potential unauthenticated WebSocket connections to the Hydro-Québec Le Circuit Electrique backend based on the HTTP Upgrade header pattern.
references:
  - https://www.cisa.gov/news-events/ics-advisories/icsa-26-188-01
author: Security Arsenal
date: 2026/04/06
tags:
  - attack.initial_access
  - attack.t1190
logsource:
  category: web_access
  product: proxy
detection:
  selection:
    cs-method|contains: 'GET'
    c-uri|contains: '/websocket' # Adjust if path is known to differ, generic placeholder
    sc-status: 101 # Switching Protocols
    cs-header|contains|all:
      - 'Upgrade: websocket'
      - 'Connection: Upgrade'
  condition: selection
falsepositives:
  - Legitimate charging station traffic if authenticated
  - Internal testing
level: high
---
title: Hydro-Québec Backend Excessive Authentication Failures
id: 9d5e6f23-2b4c-5g3d-0f1e-8c7b6d5c4b3a
status: experimental
description: Detects brute force attempts indicative of exploitation of Improper Restriction of Excessive Authentication Attempts (CVE-2026-20744).
references:
  - https://www.cisa.gov/news-events/ics-advisories/icsa-26-188-01
author: Security Arsenal
date: 2026/04/06
tags:
  - attack.credential_access
  - attack.t1110
logsource:
  category: web_access
  product: proxy
detection:
  selection:
    cs-method|contains: 'POST'
    c-uri|contains: '/login' # Generic login path, adjust to asset reality
    sc-status:
      - 401
      - 403
  timeframe: 2m
  condition: selection | count() > 20
falsepositives:
  - Misconfigured equipment
  - Application bugs
level: medium

// Hunt for WebSocket Upgrade requests to known Hydro-Québec Backend IPs
DeviceNetworkEvents
| where RemotePort in (80, 443, 8080) // Common web service ports
| where InitiatingProcess has_any ("curl", "python", "perl", "openssl") // Common tools for manual probing
| extend ParsedFields = parse_(AdditionalFields)
| mv-expand ParsedFields
| where ParsedFields.Key == "Upgrade" and ParsedFields.Value =~ "websocket"
| project Timestamp, DeviceName, SourceIP, DestinationIP, RemotePort, InitiatingProcess
| sort by Timestamp desc

// Hunt for excessive failed login attempts
DeviceProcessEvents
| where ActionType in ("LogonFailure", "AuthenticationFailure")
| summarize count() by DeviceName, AccountName, bin(Timestamp, 5m)
| where count_ > 10

-- Hunt for processes establishing connections to common websocket ports or suspicious parent chains
SELECT Pid, Name, CommandLine, Exe, Username, CreateTime
FROM pslist()
WHERE Name IN ('python', 'perl', 'bash', 'sh', 'curl', 'wget', 'nc') 
   AND CommandLine =~ '(upgrade|websocket|hydro)'

-- Check for established network connections on the backend host
SELECT Fd, Family, Type, RemoteAddr, RemotePort, State, Pid
FROM netstat()
WHERE State =~ 'ESTABLISHED'
  AND RemotePort IN (80, 443, 8080)

#!/bin/bash
# Remediation verification for CVE-2026-20744
# This script checks if the backend is enforcing auth on Websocket upgrades.
# Requires 'curl' and 'jq' (optional for JSON parsing).

TARGET_HOST="127.0.0.1" # Replace with actual backend IP
TARGET_PORT="8080"       # Replace with actual listening port

echo "[*] Checking CVE-2026-20744 vulnerability status on $TARGET_HOST:$TARGET_PORT..."

# Attempt a WebSocket handshake without Authorization headers
# A vulnerable server will reply with 101 Switching Protocols.
# A patched server should reply with 400 Bad Request, 401 Unauthorized, or 403 Forbidden.

RESPONSE=$(curl -i -N \
     -H "Connection: Upgrade" \
     -H "Upgrade: websocket" \
     -H "Host: $TARGET_HOST:$TARGET_PORT" \
     -H "Origin: http://$TARGET_HOST:$TARGET_PORT" \
     -H "Sec-WebSocket-Version: 13" \
     -H "Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==" \
     http://$TARGET_HOST:$TARGET_PORT/ 2>/dev/null | head -n 1)

if echo "$RESPONSE" | grep -q "101"; then
    echo "[!] VULNERABLE: Server accepted WebSocket upgrade without authentication (HTTP 101)."
    echo "[!] IMMEDIATE ACTION REQUIRED: Apply vendor patches immediately."
    exit 1
elif echo "$RESPONSE" | grep -q -E "(401|403|400)"; then
    echo "[+] SECURE: Server rejected unauthorized WebSocket upgrade attempt ($RESPONSE)."
    exit 0
else
    echo "[?] UNKNOWN: Unexpected response. Manual verification required."
    echo "    Response: $RESPONSE"
    exit 2
fi