Public WiFi – When the Person at the Next Table is Reading Along
Quickly check some news, reply to an email and search for the nearest restaurant for lunch break – public WiFi hotspots offer a convenient way to get free internet access in many places, all over the world. But as tempting as this free internet access may initially be for users, it can quickly become a serious threat to all data.
Stefan Brinkhoff is aware of the problems that popular WiFi hotspots bring with them. The experienced e-commerce consultant for medium-sized companies built websites and developed online shops in his youth. Anna-Lina Köhler, a student at the Private University of Applied Sciences Göttingen (PFH) who is dealing with the WiFi issue, met the knowledgeable co-founder and CTO of locandis for a conversation.
Anna-Lina Köhler: What are the basic advantages of public WiFi?
Stefan Brinkhoff: In general, public WiFi offers a good opportunity to save data volume. Especially in buildings where data reception is limited and perhaps even below the “Edge area”, a fast internet access according to the user’s requirements is advantageous.
Anna-Lina Köhler: How widespread are public WiFi hotspots today?
Stefan Brinkhoff: Even though the spread of public WiFi hotspots in Germany is still relatively low compared to international standards, the communication network is continuously being expanded nationally. So you can expect that there will be more and more free WiFi hotspots in the future.
Anna-Lina Köhler: Why is it that more and more WiFi is being set up or offered in public spaces? Who is the driver?
Stefan Brinkhoff: Even today, there is still the problem of adequate data speed in many cases, especially inside buildings. There can be a damping effect, so that fast bandwidths, which are needed for certain applications on the digital device and ultimately demanded by the user, do not exist as standard. The offer and the constant spread of the use of public WiFi is therefore fundamentally positive.
With WiFi, the data is on the presentation plate
Anna-Lina Köhler: What dangers or security concerns should be considered when it comes to public WiFi?
Stefan Brinkhoff: In public networks, the data is basically on the “presentation plate”. Any other user surfing in the same public WLAN network can theoretically view the data packets that the digital terminal device sends or receives, as the data is transmitted unencrypted between device and network. This problem tends to exist at all nodes on the internet. If you share your WiFi with other users, the hacker only needs to sit at the next table to then exploit the vulnerabilities of the unencrypted data.
Anna-Lina Köhler: Do you have an example?
Stefan Brinkhoff: A conceivable and quite practical example would be the use of public WiFi hotspots in hotel lobbies by business travelers. Whether it’s just to quickly send business emails or actually to work with internal company data, in the worst case these critical information are shared with all other hotel guests. All information that the digital terminal device exchanges with the public network can therefore ultimately be threatened.
Anna-Lina Köhler: How can such an attack on one’s own data typically work?
Stefan Brinkhoff: The so-called “Honeypot technique” is common. This means that a second hotspot with the identical name is broadcast next to the correct public network. So the same WiFi name is thrown out, so that the device cannot differentiate between a real and a fake network. The attacker thus positions himself between the network and the provider and thus gains control. Even though many cell phones and apps nowadays rely on internal SSL encryption, the hacker can still find out who is being communicated with and which pages are being used and thus create a real user profile.
Install VPN tools and always perform updates
Anna-Lina Köhler: How can the user best protect himself from such dangers? What security precautions are there?
Stefan Brinkhoff: The best way to protect yourself is to set up a VPN connection in public WiFi, which then encrypts the data and makes it no longer attackable from the outside. For this, it is usually enough to install a simple VPN tool. Also, all updates should be installed regularly to keep the operating system up to date and to offer hackers a minimal attack surface.
Anna-Lina Köhler: And what can users do if their data has already been hacked?
Stefan Brinkhoff: In such a case, it is important that all active sessions in the accounts are ended and that work is not continued on the identified hardware under any circumstances. It is also advisable to change all passwords. Free WiFi hotspots are basically a positive and practical thing, for example to briefly check the weather. If you really want to make sure that online banking data or company data remains internal, you should not edit this data in public hotspots for safety reasons – and share it with the person at the next table.
Stefan Brinkhoff, locandis founder, in conversation with Anna-Lina Köhler
Photo: Caleb Minear/Unsplash