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The hidden dangers of using public WIFI

GeneralEdward KiledjianComment

There are plenty of reasons to love WIFI (over wireless). It's free, fast and usually reliable. Often times though, its not a WIFI network you control (think coffee shop, retail store, mall, fast food joint, etc). Sure WIFI is ubiquitous but most of it is controlled by someone else which means is could and should be considered a hostile environment.

WIFI is a hacker playground

Man In The Middle Attack

A Man In The Midle (MITM) attack is an oldie but goodie. It allows a third party to intercept your communication. If successfully performed, an attacker can present a fake "hacker version" of a site you are trying to visit in the hopes of infecting your machine or harvesting your credentials.

An innocent use of this technology is when a WIFI provider intercepts your web browsing request (when you first connect to their network) and injects a logon or terms acceptance page (captive portal). This is a benign use of the technology but bad actors can use this to inject malicious code to infect your computer or trick you.

What you should do: Ensure any site you visit requiring a login or requesting private information is using an encrypted SSL/TLS connection (aka the green lock icon in Chrome). Look for a URL that starts with https instead of just http. Make sure the lock icon is green. 

We are seeing more and more sites switch to encrypted https but many have not made the jump yet. You should also add a free browser plug-in called HTTPS Everywhere. It is a free plug-in developed by the Electronic Frontier foundation and the TOR project which automatically rewrites requests to the secure https protocol when supported by the site. 

Fake WIFI networks

This is a very easy to use trick that is successful any time I have tested it. I basically setup a very strong signal WIFI network with carefully chosen (trustworthy sounding names) that get users connecting to it and then I simply do what I want to do and resend the traffic to the local establishment's free WIFI network thus performing a Man In The Middle attack. 

I can even use the same WIFI name as the local establishment's and your device will automatically connect to my rogue network if my signal is stronger (that's why automatic connections to untrusted WIFI networks can be a very bad thing unless you are always on VPN). I can create one of these network with cheap devices but my preferred tool is the WIFI pineapple. 

What you should do: Be weary if you see multiple networks with the same name at your local coffee shop. It doesn't always mean there is an attack happening but it should give you pause. The real solution is to always use a VPN network when connecting to a WIFI network you don't directly control.

Collecting your wireless information

Sniffing network traffic is a technique used by corporate network administrators to collect information to perform debugging and to try and identify system issues. Sniffing is basically collecting all (some or most) traffic flowing over a network. In the wireless world, this is made incredibly easy and can be done by hackers without anyone's authorization. All it requires is a special (cheap) wireless network card configured to startup in a special mode and then they can capture all the traffic flowing over the wireless network. Once you had the hardware, you simply need a free software like Wireshark to start capturing all wireless traffic. 

Anyone interested in WIFI testing should buy a WIFI Pineapple. You can't call yourself a real security pro without one. I'll wait while you go and buy from from here. (no that is not an associate link and I do not get anything for recommending them. It is just an awesome product).

What you should do: Ensure any site you visit requiring a login or requesting private information is using an encrypted SSL/TLS connection (aka the green lock icon in Chrome). Look for a URL that starts with https instead of just http. Make sure the lock icon is green. Encrypted traffic can be captured but is all garbled up and useless to the attacker. Or you can use a VPN service (which I will talk more about later).

Stealing cookies

No.. not cookies from a coffeeshop but cookies used by websites to authenticate your session. Most websites drop a session cookie in your browser after you log in so you don't have to log-in every-time you visit the site operators page. Most major sites go to great lengths to protect this cookie but many don't and attackers will try to steal these when patrons use unencrypted websites. By stealing the cookie and using it from the same location, many sites will be tricked into thinking the user is logged in and will allow him/her to perform actions without additional checks.

What you should do: Ensure any site you visit requiring a login or requesting private information is using an encrypted SSL/TLS connection (aka the green lock icon in Chrome). Look for a URL that starts with https instead of just http. Make sure the lock icon is green. Encrypted traffic can be captured but is all garbled up and useless to the attacker. Or you can use a VPN service (which I will talk more about later).

Peekaboo I see you

When organizing a security test for a company, my preferred method of attack is attacking the bag of mostly water (aka the human). Humans are usually careless, clumsy and easy to trick. It is much easier to compromise a human than an IT system.

Shoulder surfing is the art of looking over someone's "shoulder" as they type protected information info a computer system. This could be a building entry code, the PIN for your ATM card or a site password. 

This is an especially easy attack when you are in a crowded area where it feels normal to have people close by (packed coffee shop with tight tables, a bus, etc).

What you should do: When I travel, I have a 3M privacy filter on my computer screen to make it more difficult for people around me from seeing my private on-screen information from onlookers. Additionally I always cover any keypad when entering my PIN and never enter passwords when in a crowded area. The important thing is to realize this could happen and pay attention to your surroundings. 

What about that VPN option

My next article will be about 1 or 2 VPN providers that I trust and use but for now, I'll write about what a VPN is. A Virtual Private Network is a special technology that creates a secure connection between your device and that of the VPN provider. That means anyone eavesdropping (digitally) on your WIFI or LTE connection will only see garbled 

Of course the VPN provider will see all of your traffic as they send it to the general internet from their servers but at least you protect yourself from local WIFI attacks. Additionally, anytime you use an https site, that traffic is protected and even your VPN provider cannot see the content of that traffic.

As an example: 

I am sitting in a coffee shop browsing facebook via their mobile website. Their mobile website is protected because it uses TLS (https). I distrust public WIFI, I also have a VPN active.

This means that my connection (all traffic to and from the internet to my device) is encrypted inside that protected VPN tunnel [from my device until the server of the VPN provider] thus no one in the local coffee shop sees where I am browsing and what I am sending/receiving. This protects you from all those local attacks.

Because I am using the facebook website on my device, it is also using protected https which means traffic for that site is encrypted a second time between me and Facebook. This means that the VPN provider knows I visited facebook but can't see anything else.

Obviously you have to trust the VPN provider not to profile you but this is much better than trusting a coffee shop WIFI or even your wireless LTE carrier.

The US Government is moving to kill a law preventing carriers from selling user data to the highest bidder. This means even your home internet provider or wireless carrier will probably start tracking your every move on the internet and selling it to marketing companies. Many people should start thinking about running a permanent VPN from their home router to the internet to protect themselves from this type of profiling.

For those that want a fast, easy and reliable VPN appliance, read my review of the InvizboxGO here