Can someone crack the public service PRE

Security: You have to pay attention to this with WLAN hotspots

Open WiFi networks are useful - but they can also be dangerous.
Photo: teltarif.de Last week, Kabel Deutschland launched its open, free WiFi network in Berlin. According to the company, 1,000 users have already registered on the free WiFi hotspots in the last hours before the announcement, shortly after the technical activation of the systems the evening before. That was - at least in theory - not without danger for them, after all, they didn't even know where to log in and who owned the WLAN access. But well-known WiFi hotspots can also be a source of danger. There are therefore a few things that you should consider when using a WiFi hotspot - regardless of whether it is free or paid.

Open WiFi networks are useful - but they can also be dangerous.
Photo: teltarif.de The 1,000 Pre-Start users apparently carried out a WLAN scan on the street and found the "speaking" transmission identifier "30 Min Free WIFI". Tempting to use it and log in. Fortunately for the users, this identifier with Kabel Deutschland was a reputable provider who had made the technical activation before the official announcement. The users couldn't know that. As well as a malicious hacker, it could have equipped its router with this identifier and henceforth read the data traffic of the users used. Even the upstream portal page for agreeing to the terms of use can be falsified with some know-how. If a hacker were to hide behind an identifier, he could read the entire data traffic with little effort. And that without having to be in the cold or in the same public place. A complete recording of the transmitted data would also be possible, so that he can later browse through the data through sensitive and interesting data.

Unencrypted data can be read in every WLAN network

But there is also danger at every other public WiFi hotspot. Regardless of whether it is completely free of charge as with Kabel Deutschland in Berlin, Telekom or the hotel WLAN: Third parties can always read data if they want. For normal users, this means: be careful when transferring personal data as long as it is not encrypted. For example, anyone who surfs normally on Amazon can also read their surfing behavior. The transmission is not encrypted until the user data has been entered. But by then the hacker usually already knows the name of his victim, which books or goods he is interested in and, based on the section "You might be interested in this" provided by Amazon, what other shopping behavior the surfer displays.

Anyone who is in the network with their smartphone also uses an app for many things. Be it Facebook, home banking or Amazon. The disadvantage: it is often impossible to tell whether the data transmitted from here is encrypted or not. In a few apps you can set whether the transmission should be encrypted or not. In any case, encryption should be activated here to be on the safe side. In any case, it is the rule for home banking apps that they are encrypted. But anyone who inadvertently opens their app for stock market watch services and looks into their depot shows third parties directly that they have sufficient financial resources. A look at the app of the airline or the train informs the reader about the travel plans and in other ways the address of the person observed can certainly be read out. E-mails are also not safe from being read.

Protection on the laptop: VPN services

The same applies to the use of WLAN networks with a laptop. Here, however, you can protect yourself relatively easily by using VPN services. However, these are usually not available for free. It is also easier for the computer to recognize whether a (browser) connection is encrypted or not. A login on Facebook, for example, is not encrypted as long as the https version has not been called up explicitly. Only then can the uninvited reader not simply take power over the account.

The e-mail account in the e-mail program also transmits the e-mails unencrypted - unless the user sets it differently. However, encrypted transmission must also be supported by the provider. If there is no encryption, all transmitted e-mails can be read - and not just those: the login data are also at risk. Once they are known, e-mails from strangers can then also be sent.

By the way: commercial hotspots are usually not encrypted. Some hotels or caf├ęs encrypt their WLAN networks and give their customers the password. That seems certain at first, but it isn't. Every user who is also in this network - for example in the next room or at the next table - can read along as if the network were open

In a nutshell: You have to pay attention to this in the WLAN

In a nutshell: Use your smartphone and computer in the public WLAN as if someone were standing behind you and reading along. You shouldn't call up what nobody should see - unless the data is encrypted. This cannot always be seen with apps. Only partial security can be achieved on the laptop via VPN. Logging into completely unknown networks should generally be avoided.

If you want to be on the safe side, you should only use networks that you can administer yourself and thus know the other participants. Otherwise, the only thing that helps is to switch to the cellular network. Several devices can then be supplied via tethering.