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Cyber Snapshot - Uninvited Guests - Securing Guest Networks

Introduction

Guest networks can be vulnerable: often they are overlooked within organizations and have few (or no) cybersecurity features enabled to protect their users. If a bad actor gains access to a guest network, any device connected to that network could be compromised. Many organizations utilize guest networks to segment Internet Technology (IT) and Internet of Things (IoT) devices such as: smart thermostats, smart refrigerators, smart washing and drying machines, voice assistants, smart garage doors, home security cameras, and smart doorbells. This is to protect valuable IT data from typically less secure IoT devices. When trying to segment and protect networks by separating IT from IoT there are potential for significant security risks if they are not properly managed. 

Understanding Guest Networks

Guest networks often exist at businesses and homes to provide Wi-Fi access to visitors, and there is generally little to no security utilized like, passwords, captive portals, or an access code to join the network. Although guest networks are seen as a safe and easy way to access the internet, they can be used maliciously or even unknowingly to gain unauthorized access to devices connected to the guest network. Additionally, if a bad actor accesses a guest network, they can carry out malicious activities, even commit crimes. 

Having a guest network is a good security feature when used correctly. Utilizing a guest network segments legitimate business operations from more risky personal use where temporary access is desired like checking personal email, internet shopping, and using social media. This type of temporary access is useful as the segmentation helps protect more sensitive data on the primary wireless networks.

Guest networks are usually forgotten about when assessing organizational security issues; they often utilize default settings/passwords and do not receive regular security or software updates. Further, activity on guest networks usually is not monitored or logged, leaving an open access point for bad actors to wreak havoc. 

Attack Vectors

Man-in-the-middle (MitM) attacks are a common way that untrusted guest networks can be used maliciously. In this type of attack, an unsuspecting victim connects to a malicious network that appears legitimate, while the attacker monitors the victim’s network traffic to collect sensitive data for later use.

Once access is gained to the network, a bad actor may move laterally, and access other devices connected to the network. This includes IoT devices which are often left unpatched and can be exploited at this time as well. 

Finally, users should be aware of inherent risks in some of the technology itself. While you may want an IoT enabled security camera to feel more secure, others may want to use that technology to surveil you. Recently, the Federal Trade Commission filed a complaint against Ring, stating that employees working for Ring had illegally viewed customer security camera and doorbell videos, and that they failed to stop hackers from taking control of their customer’s devices.

Best Practices for Guest Networks

The MC3 recommends strong encryption be enabled (such as WPA3 encryption) on all guest networks. Guest networks connections should be isolated from your primary network and devices. Network passwords should be complex (unique, with numbers, capital and lower-case letters, special characters and spaces or hyphens included) and 16 characters in length. Using a unique Service Set Identifier (SSID), enabling firewalls, logging, and configuring traffic restriction rules are also recommended. If a guest network is not needed or desired, disabling the guest network entirely, or at least disconnecting guest network access to local connections is another option.

 

June 2, 2025
CS-03-2025