Using SMS for the Internet of Things (IoT) is critical to connected systems, even as Internet Protocol (IP)-based protocols gain wider adoption, writes April Miller, Managing Editor at ReHack Magazine. It offers consistent reliability and minimal infrastructure demands, which makes it especially valuable in remote or resource-constrained environments.
Organisations must recognise that these advantages come with inherent security limitations, requiring careful planning and safeguards to ensure secure and resilient IoT communication. This balance between accessibility and security makes SMS a strategic and carefully managed component of modern IoT architectures.
The role of SMS in IoT communication
SMS can operate effectively in remote and low-connectivity environments where traditional data networks may be unreliable or unavailable. It requires minimal power, which makes it ideal for constrained devices designed for long operational life cycles. Integration is relatively straightforward compared to data-based protocols, reducing development effort and infrastructure complexity.
These advantages position SMS as a practical communication option in deployments that prioritise reliability and broad accessibility. Its independence from continuous internet connectivity allows devices to remain functional in challenging conditions. This capability proves valuable in industries such as logistics and environmental monitoring. As a result, SMS supports critical operations where consistent communication cannot be compromised.
Security gaps in SMS transmission
SMS for IoT systems operates without end-to-end encryption and creates inherent security limitations for connected systems. Cellular protocols do not provide end-to-end encryption for text messages or voice calls, which means data can be accessed at multiple points along the transmission path. Messages travel in plaintext across carrier networks and increase the likelihood of interception or unauthorised visibility.
This level of exposure within telecom infrastructure reinforces the need for additional security controls when SMS is used in IoT environments. Without encryption at the application layer, sensitive commands or data can be exposed to unintended parties. As a result, organisations must treat SMS as a low-trust channel and design systems that assume potential compromise.
Risks associated with SMS-Based IoT messaging
SMS introduces several risks that organizations must actively manage. Sender spoofing and impersonation attacks allow malicious actors to mimic trusted sources and issue unauthorized commands. Interception remains a serious concern, particularly through telecom vulnerabilities, such as SS7. Attackers can exploit weaknesses in the protocol to intercept calls and messages, gaining access to private communications that are often assumed to be secure.
Replay attacks further increase risk, as previously captured messages can be resent to trigger unintended device behaviour or system responses. These threats can lead to unauthorised control of devices or manipulation of operational data. In high-stakes environments, even a single compromised message can cascade into broader system vulnerabilities if proper safeguards are not in place.
Methods for verifying message authenticity
Verifying message authenticity remains critical when using SMS for IoT environments. Shared keys or token-based authentication provide a foundation for validating trusted communication, with authorisation tokens offering flexibility when user access fluctuates based on data conditions or special events. Tokens also support repeated granting and rescinding or access, which makes them well-suited for dynamic IoT deployments.
Cryptographic message signing strengthens integrity by ensuring messages have not been altered in transit. Safe listing trusted numbers or endpoints adds control, limiting interactions to approved sources and reducing exposure to unauthorized commands. Time-based validation mechanisms, such as timestamps, can further prevent replay attacks. These approaches create a layered authentication model that improves trust across SMS-driven interactions.
Best practices when using SMS for IoT systems
SMS is most effective when used for alerts and fallback communication rather than as a primary data channel. High user engagement supports its reliability, with people checking their phones about 186 times a day in 2025, making SMS well-suited for time-sensitive updates. Sensitive information, including credentials or critical commands, should be excluded due to inherent security limitations.
Ongoing monitoring of message activity helps identify anomalies and potential threats early. Regular firmware updates and timely security patching further strengthen device protection and overall system resilience. Clear usage policies ensure that SMS is applied consistently within defined security boundaries. This disciplined approach reduces risk while preserving the operational advantages of SMS in IoT deployments.
Building a hybrid communication approach
When using SMS for IoT, it’s ideal to prioritise IP-based protocols for primary data exchange while reserving SMS for failover scenarios. IP connections introduce greater complexity and require increased power and memory, yet they offer the advantage of having no range limitations. This makes them suitable for continuous and data-intensive operations. SMS serves as a reliable backup when primary networks become unavailable or unstable.
Communication methods should be aligned with data sensitivity levels, which ensures that critical or sensitive information is transmitted through more secure channels. This balanced approach allows organizations to maintain reliability without compromising security. Careful system design ensures that failover mechanisms do not introduce new vulnerabilities. Clear prioritisation of communication channels also improves performance and scalability.
Balancing reliability and security in SMS-based IoT communication
SMS for IoT remains a practical communication option in modern connected systems. Its security limitations require layered protection strategies to ensure safe and reliable operation. Strategic use of SMS reduces risk while preserving the reliability that many deployments depend on.
Author Biography:
April Miller is Managing Editor at ReHack Magazine, based in South Carolina, USA.
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