Malicious SIM Cards Threaten Cellular IoT Devices

Research from the University of Birmingham and the security firm Fuzzware has revealed that malicious SIM cards are capable of taking control of various IoT devices. These SIM cards can execute commands specified by attackers, leading to significant security risks. The tests included 26 mobile phones and cellular modules used in various devices such as electric vehicle chargers, industrial routers, and vehicle telematics systems. The researchers found that the malicious SIM cards can not only execute simple commands but also enable complex attacks. These attacks could impair the entire functionality of the device and potentially lead to data loss or theft.

The possibility of an attacker gaining control over a device poses a serious threat to the security of IoT applications. A key finding of the study is that the security mechanisms of most cellular modules are insufficient to prevent such attacks. The researchers pointed out that many of these modules are not designed to defend against attacks from malicious SIM cards. This could leave companies relying on IoT technology vulnerable to cyberattacks. The tests showed that attackers, by manipulating the SIM cards, are able to alter the firmware of the devices.

This allows them to take control of the hardware and use the devices for their own purposes. The researchers emphasize that this type of attack is not merely theoretical but could already be occurring in practice. Another aspect of the study is the need to revise the security standards for cellular modules. The researchers recommend that manufacturers of IoT devices and cellular modules urgently take measures to protect their products against such attacks. This includes implementing more robust authentication and encryption methods.

The findings of this study also raise questions about the responsibility of mobile network operators. These providers may be obligated to educate their customers about the risks of malicious SIM cards and offer appropriate security solutions. Collaboration between manufacturers, mobile network operators, and security researchers is seen as crucial to ensuring the security of IoT devices. The study has also attracted the attention of regulatory authorities, which may introduce new policies regarding the security of cellular modules and IoT devices. These policies could aim to raise security standards and hold manufacturers accountable for security vulnerabilities in their products.

Researchers presented their findings at a cybersecurity conference held on August 12, 2026. The presentation garnered significant interest and led to intense discussions about the security challenges in the field of IoT technology. Experts are calling for a faster response from the industry to the identified security risks. The vulnerability caused by malicious SIM cards could have far-reaching consequences for the industry.

Companies relying on IoT technology must be aware of potential threats and take appropriate measures to protect their systems. The researchers recommend that companies conduct regular security audits and update their devices frequently to close security gaps. The study highlights the urgency of developing security solutions specifically tailored to the challenges of IoT devices. Implementing such solutions could help strengthen trust in the security of IoT technologies and promote acceptance in the industry. The researchers plan to publish their findings in a scientific journal to further advance the discussion on the security of cellular modules and IoT devices. The publication is expected in the fourth quarter of 2026.