Public Wi-Fi: Stealing Secrets in the Air

Open and closed public Wi-Fi networks

Would you like some coffee with your unsecure Wi-Fi?

‘Free Wi-Fi’ – a phrase so commonly heard today that we have come to expect it in most public places. The vast majority of hotels, restaurants and coffee shops today offer Wi-Fi for customers. In recent years, exploits using equipment such as the Wi-Fi Pineapple have captured the attention of IT Professionals and have raised awareness of the vulnerability of public Wi-Fi networks. However, in reality such attacks are rare. A much more significant issue is the ease with which anyone can quietly view unencrypted internet traffic. But how exactly does this occur and how can it put Wi-Fi users and corporate data at risk?

Open Wi-Fi Networks

Most businesses and public places that offer free Wi-Fi do so with an open Wi-Fi network. This allows users to connect to an access point without the need for a password. Customers in the vicinity simply select the network from their detected list by their device and connect. However, most users are unaware of how easy it is for anyone nearby to gain access to traffic sent over this network. With basic IT skills and simple utilities, which are for example built into Macbooks, in the right location, anyone can sniff packets and perform a packet trace on a Wi-Fi network with unsecured traffic. This means that when using the network, the third party is able to see both the content of the user’s unencrypted traffic and their browsing destination. This becomes dangerous when the content or destination of the user’s traffic is sensitive or confidential.

Closed Wi-Fi Networks

Unlike open networks, some public Wi-Fi connections do require a password to access the internet. However, despite their seemingly more secure systems, hackers can intercept them relatively easy too. In reality, most public places that require a password to access their free Wi-Fi do so to limit access to paying customers only. Because of this, password protection actually does very little to prevent third parties attaching to closed networks and sniffing the same traffic that is visible on an open Wi-Fi network. Even when the hacker does not know the password due to the limitations of Wi-Fi, widely available tools such as Wifite or airodumping-ng can be used to connect to a router, capture packets, and decrypt the password.

WAP2 passwords in particular, if poorly configured, can be ascertained relatively easily in this way. This allows anyone to attach to a network once they are in close proximity to the AP. Once hackers gain access to the network, they can see all unencrypted traffic passing through. This includes the websites visited and users’ login credentials.

Wired Network Connections

Wired networks provide some security for public internet access. Given the need for a physical connection, they are much more difficult to hack. Malicious actors need to find a cable point to plug into. Presumably these are only available in particular physical locations making it harder to covertly hack or access a network. However, hacking wired networks is not impossible. Once accessed, attackers can see the same information as on an open wireless network.

What to do?

In a recent report, it was discovered that 44% of organizations’ mobile workers connect to public networks more than half the time that they are working. As well as this, in 2018 87% of workers admitted to potentially putting company data at risk by accessing email, bank accounts and financial information while using public Wi-Fi, highlighting the real danger currently facing companies.

So what can they do to protect their sensitive data? In the case of public Wi-Fi the best protection is prevention. Employees need training to avoid sending sensitive information unencrypted over any network. They should also be aware that on Wi-Fi or wired network, data received or sent can viewed by anyone.


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Read the latest news on enterprise mobile security direct from the specialists.