Real Time Operating System (RTOS) — Security and Protection

The "RTOS" or "real-time OS" is one of the most crucial components found in today's embedded systems. It is responsible for everything from task scheduling to supporting high-level languages like C and Python. It's a crucial part of making sure that embedded devices, such those used in the Internet of Things, robots, and digital communication systems, execute tasks predictably and on time.

RTOS is being used to power automated missiles and space satellites. Its objectives are to provide capabilities for time-constrained programes, which must execute within a specific time frame, while reducing delays such latency brought on by interrupts and thread switching. Real-time performance is therefore the primary factor considered when evaluating RTOS for the majority of applications.

The security of RTOS is divided into two primary categories. The ability to keep processes distinct so that one activity does not interfere with another is the first aspect of the RTOS's security. This factor also has an impact on the system's stability because any threat could cause the system to enter an unknowable state and fail.

The second one has to do with RTOS networking. In the current IoT era, RTOS rarely functions independently. It often manages specific automated equipment and is frequently connected to a monitoring system that communicates with other RTOS to manage a whole facility. These networks are frequently referred to as distributed control systems (DCS) or supervisory control and data acquisition (SCADA) (DCS). Therefore, it is crucial to ensure the security of communication between RTOSs as well as inside them.

Several IoT devices use the real-time operating system VxWorks. Many different types of companies, including security firms, manufacturing firms, and the healthcare sector, trust VxWorks to manage their vital devices in everyday operations.

In July 2019, the IoT device security company ARMIS discovered 11 vulnerabilities in this RTOS, including six significant flaws collectively known as URGENT/11. This issue made 200 million important devices vulnerable. According to research from security company Armis, the flaw may have given remote 

There can be various ways in which the system can be attacked 

Code injection is the most common and dangerous cyber attack. This attack is implemented by feeding and running arbitrary codes on a computer or real-time operating system. The attackers aim to urge control of your program and alter its command flow also as trigger the program to execute malicious codes.

Some RTOSs lack memory management units. They believe a flat shared memory unit to interchange communication. The message sharing platform is sort of a board where people write messages and their replies. If the incorrect person gets to the message and alters it before the proper person reads it, it might end in a system crash. That is how unmanaged shared memory threatens your system’s security

This normally occurs when a process is denied memory access or resource access, due to a simultaneous ongoing process. For example, if one program takes up more memory, it denies other programs their required memory amount; or if a program hangs an endless loop, other programs lack adequate CPU time. This can be caused by bad programming, a virus, or a hacker who can access the system externally.

In RTOS different processes running simultaneously sometimes need to share resources such as I/O or memory. And the access to these resources is given based on the priority. So mutual exclusion (to avoid context switching) and process priority methods try to solve data and processor sharing problems respectively. But both methods applied at the same time give rise to an issue called priority inversion, which leads to inconsistency.

Though encryption of data is considered one of the ways to secure data while transmission, there are high chances that this data can be intercepted, decrypted, and altered using various techniques. There are techniques such as hashing for more secure data transmission, but embedded systems find it costlier due to the high computational power and memory requirements.

A real-time OS relies on messaging queues to transfer information. Most RTOSs lack protocol to make sure that messages are from safe and bonafide sources. As long because the messages are delivered via a legitimate handle, they’re going to be implemented.A real-time OS accelerates the event schedules and makes the working of any system more efficient. like any technology, however, it’s critical to make sure that each one security gaps are sealed before an attack hinders the operations and therefore the system faces a catastrophic disaster.

Solutions to these attacks :

There are a couple of ways in which may help to form RTOS safer by resolving the safety problems and protecting the system:

The Multiple Independent Level of Security method is a highly preferred framework to resolve security issues. It mainly works on the principle of divide-and-conquer, where a process is divided into multiple independent levels, and applying security protocols to independent kernels. This not only resists the attackers from cracking the system but also isolates the fault, which means that the failure of one partition would not affect the other.

The RTOS system should have a secure identification and authorization mechanism in place to verify a user If users aren’t properly identified and authenticated, then the embedded device is potentially susceptible to access by unauthorized users. User accounts within an embedded device shouldn’t be static in nature. Features that allow separation of user accounts for internal web management, internal console access, also as remote web management and remote console access should be available to stop automated malicious attacks.

RTOS network firewall –

Modern RTOS have network firewall capabilities and any device with a network connection should run with a firewall in place. Firewalls are standard practice for desktop and server systems — embedded devices are increasingly connected to the same networks as larger-scale devices. The firewall should only allow communication via required TCP/IP ports — a firewall is a good first line of defense against network attacks. The firewall ensures all non-essential ports and services are closed off and only allows ports that are specifically configured to be open and available for connection.

Sufficient allocation of storage space :

Quotas are a security control that’s implemented to guard the device from running out of disk, memory, or CPU. As an example, if a DDOS attack is formed against the RTOS system with the intent of overusing the CPU, an unprotected device could essentially appear to freeze up. By being able to set limits on the number of critical resources –such as CPU — a task is able to consume, the overall system is protected from such an attack.

Secure Data Storage :

RTOS system should have capabilities to store data securely using techniques such as encryption and partitioning. No assumptions should be made about the classification and privacy of data used in RTOS systems.

RTOS are developed considering the time, space, computational cost constraints. The rise in its use, access, and networking have created the need for securing the system. The security of an RTOS starts at its design and development phase. In this way, software professionals attempt to build software that can withstand attacks proactively.