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IoT devices are becoming more and more prevalent in the corporate world, as they allow us to automate tasks and activities without manual intervention, which increases the risk to the organization by increasing the attack surface available to attackers. This is because IoT devices can act as entry points to the organization’s internal network. In order to reduce the security impact of these devices the attack channels and threats from the devices need to be mitigated. This can be done by implementing the suggestions in this paper

IoT or Internet of Things is a collection of devices that are connected to the internet and can be controlled over a network or provide data over the internet. It is one of the fastest growing markets, with enterprise IoT spending growing by 24% in 2021 from $128.9 billion. (IoT Analytics, 2021). This massive growth brings new challenges to the table as administrators need to secure IoT devices in their network to prevent them from being security threats to the network.

IoT devices allow us to manage, monitor and control devices and sensors remotely which in turn allows us to automate tasks and activities without manual intervention. But this capacity comes at an increased risk of vulnerability due to a massive increase of the attack surface available. They are becoming more and more prevalent in an enterprise setting, especially in the office automation and operational technology areas. This increases the risk to the organization by increasing the possibility of threats in areas that traditionally don’t pose cyber security risks.

IoT devices can act as entry points to an organizations internal network and be used to exfiltrate data from the network without raising flags. In 2018, attackers used a compromised IoT thermometer in the lobby aquarium of a casino to breach their system and exfiltrate their high-roller database (~10GB of data) out of the corporate network to servers they controlled via the thermostat. (Williams-Grut, 2018).

In this paper we will review some of the major threats and attack channels targeting IoT devices and look at how we can reduce the impact of these threats on the enterprise security.

IoT Threats and Attack Channels

IoT devices have multiple attack surfaces due to their design and usage. We will cover the major vulnerabilities in this section along with mitigation steps for each threat and attack channel.

A. Physical Vulnerabilities

Since these devices are usually physically deployed in the field in addition to the typical software and communication vulnerabilities, they are also vulnerable to physical attacks where the device can be physically modified to gain access. Some of the examples of Physical attacks are as follows:

• Attackers physically remove the device memory or flash chips to read & analyze the data and software on the chip.
• Attackers tamper with the microcontroller to gain access to or identify sensitive information
• Physically modify the device to return incorrect data or telemetry. For example, camera’s or motion sensors overseeing sensitive locations could be modified to ignore breaches.
• Use the device connectivity to act as a bridge to gain access to the corporate network.
• Attackers authenticate locally to the device using debug interface on the device to gain access to the device internals

The best way to protect against such attacks is to ensure the following preventive measures are taken for all devices on the network:

• Ensure that the device or sensor is not easily accessible physically.
• All sensors and devices should have tamper proof seals installed on them with regular checks to verify that they are not tampered with.
• Unused ports, connections, diagnostic connectors etc should be physically disabled when possible.
• If possible, ensure the devices have hardware-based security checks on it.

B. Outdated Firmware

Many of the IoT devices and sensors run older versions of Linux with no easy way to update the firmware, installed software or applications to the latest versions. This creates a major security risk as the device is running software with known security vulnerabilities which allows attackers to easily compromise a device.

There is no easy way to resolve this problem and protect the devices as a lot of these sensors and devices are not designed with security in mind. The best way to approach this problem is to ensure you are working with reputable device manufacturers who will ensure that appropriate support and updates are going to be available for the device/sensor.

The organization should review the recommendations by the IoT working group of the Cloud Security alliance on how to perform IoT Firmware updates securely and regularly. (Khemissa et al., 2018) The should also include the IoT sensors and devices in the organization’s update cycles which will allow them to ensure that patches and updates are installed in a timely manner on them.

Another option is to explore installing open source firmware and software on the IoT device/sensor if this option is available. The opensource firmware’s are usually updated more frequently and can be customized to better secure the device.

C. Hard Coded Passwords/Accounts

Some of the IoT devices have hard coded account passwords that cannot be changed, and this gives an attacker backdoor access to the device that is difficult to protect against. Hardcoded passwords are particularly dangerous because they are easy targets for password guessing exploits, allowing attackers to hijack firmware, devices, systems, and software etc. A famous case of such an exploit was found in 2017 when researchers found default hardcoded passwords in IoT camera’s manufactured by Foscam. (Heller, 2017) that gave admin access to anyone who used them. These passwords allow an attacker to gain access to the device and use it as a launch surface against attacks on the network.

Another famous attack exploiting this was by the Mirai malware in 2016. It scanned for and exploited Linux-based IoT boxes with Busybox (such as DVRs and WebIP Cameras) using hardcoded usernames and passwords. Once it gained access these devices were enrolled in a botnet containing over 400,000 connected devices which were then used to perform DDoS attacks on major companies across the world. (Fruhlinger, 2018)

To protect against these attacks, we should ensure the default passwords on all devices are changed frequently. An active pentest against the device should be conducted to uncover any hidden or hardcoded accounts. If any are found, the manufacturer should be contacted to prove an update to disable these accounts.

D. Poor IoT device management

A study published in July 2020 found that almost 15% of IoT devices on an enterprise network were unknown or unauthorized and between 5 to 19% of these devices were using unsupported legacy operating systems (Help Net Security, 2020). These devices make up what is known as a Shadow IoT network that is implemented without the knowledge of the organization’s IT team and can be a major weak point in the organization’s security perimeter.

The best way to protect against this scenario is to ensure regular scans are done on the network to identify any unknown or new devices connected to the network. The pentest will enable us to identify these unauthorized devices which can then be incorporated into the official network and update cycle or disconnected depending the requirements. Another way to find these unauthorized devices is to monitor and analyze network connections and traffic. New devices will change the network data flow, and this can be used to identify or locate new devices or sensors connected to the network.

E. Man-in-the-Middle Attacks

Communication channels in IoT devices are usually very trivially protected and an attacker can compromise the channel to intercept the messages between devices and modify them. This allows the attacker to cause malfunctions or show incorrect data. This can potentially cause serious harm if the targeted IoT devices are connected to or managing industrial or medical equipment. It can also allow attackers to hide their tracks and physical evidence of their work.

F. Industrial Espionage & Eavesdropping

IoT devices such as cameras, microphones etc are used to monitor sensitive areas or devices for problems remotely. If an attacker compromises these cameras, they allow them to visually and audially monitor their target compromising their privacy and potentially gaining access to sensitive data or video. For example, IoT cameras deployed in bedrooms have been used to record and leak intimate videos of the residents without their knowledge. Compromised security cameras have been used to record ATM pins entered by unsuspecting users.

Other steps that should be taken to reduce risk from IoT devices on your network:

• Segregate your Networks: IoT devices should be on a separate segment of the network which is isolated from the production and user network with a firewall sitting between the two. This will allow you to block access to the production network from the IoT network which will prevent an attacker from gaining full access to the enterprise network in case they breach the IoT network.
• Enable HTTPS/Encrypted connectivity for IoT devices: All connections to and from the IoT devices should be encrypted to protect against Man-in-the-middle attacks.
• Deploy an IDS: Deploying an Intrusion Detection System (IDS) on the network can alert us to attack attempts. All alerts from the IDS should be investigated and verified.

These are just some of the attack surfaces available to attackers targeting IoT devices, in fact with the increase in computing power available to these devices they are almost mini computers and most of the attacks that impact traditional systems such as servers or desktops can target IoT devices as well with minimal modifications. So, it is essential that security trainings are conducted for all employees in the organization to make them aware of the risks posed by IoT devices and train the security team in methods to secure these devices from attackers.

Note: This was originally written as a paper for one of my classes at EC-Council University in Q3 2021, which is why the tone is a lot more formal than my regular posts.

– Suramya