What is two-factor authentication and why should I care?

806152_48409889The password is a really old way to protect computer systems, yet many systems we use rely solely on them when authenticating users. A simple password might have been a good idea when we used only a handful of systems, but times are changing. Today we need accounts for all the social media we are on, the mail accounts, accounts for on-line shops, the bank, the workplace, you name it… Frankly speaking, I have no idea how many on-line accounts I have. And I can make one confession. I use the same password on some of them, even if the important ones naturally have strong unique passwords.

And here we are at the core problem with passwords. They should be complex enough to withstand brute force and dictionary attacks (that is when hackers systematically try a large number of passwords in hope of finding the right one) and they should be different on all systems you use (to limit the damage if one account is compromised). Many complex passwords and limited brain capacity, that doesn’t work. There are systems to create and remember many complex passwords, but many people aren’t motivated enough to use them. That’s one reason why two-factor authentication is spreading fast.

Another reason to raise the security is that hackers may target a particular system. They may break into it to steal passwords or use phishing techniques to trick you into revealing your password to them. Or plant a keylogger in your system. They may get the password, but still fail to get access to your account if you use two-factor authentication.

But what is two-factor authentication? Let’s start with some theory. An authentication mechanism can use several factors like what you know (a password you remember), what you have (a smartcard or a mechanical key) or what you are (biometrics, retina or fingerprint scans for example). A two-factor or multi-factor authentication system uses at least two of these factors. The best known example is an ATM-card that you have combined with a PIN-code that you know.

The most common way to utilize this for an on-line service is to rely on your mobile phone. You start by entering your user ID and password normally. After that the system sends a unique one-time code to your phone. You type the code and get access to the system. Your phone is the “what you have” -item as the message is directed to that particular device and can’t be read by others. This requires two things; that you have registered your phone number with the service and that you have turned on two-factor authentication. Some services do promote this option actively and ask if you want to use it.

So should I turn it on? Yes, if the service is important to you. You gain a lot of security for a quite small extra effort. You may have noticed several news reports lately about hacked Twitter-accounts. One of the incidents did even impact the stock market. Twitter happens to be one of the major on-line services that doesn’t support two-factor authentication yet. Many of these incidents could have been avoided if they had support for it. Needless to say, if you tweet for a global news agency you really need more security than just a password. But most ordinary people have services that also are important enough to justify this extra security.

Nothing is perfect so what are the downsides with two-factor authentication? The extra effort to type the code after login is of course obvious. But many systems mitigate this by remembering your device and only requiring the code when using a new device. You also must have your phone with you when you log in, which you probably have anyway. Except if you have lost it, which could prevent you from accessing your accounts. Some configuration settings in your browser may also prevent two-factor authentication from working or force you to authenticate every time you log in, even on the same device. Apps that access your account may require some extra attention. They need an extra application specific password that you can create under security settings in the account’s web interface. And last but not least. The service provider must know your phone number, which normally is linked directly to your true identity. This is usually OK, but becomes a problem if you want to be truly anonymous on the site, or have other reasons to not trust them with your number.

And remember that two-factor authentication improves security a lot, but there is no such thing as perfect security. The skimming attacks against ATMs is a classic example. The malware Perkele targets Android devices and works together with desktop malware to defeat on-line banks. Perkele proves that on-line services’ two-factor authentication can be attacked, but this is not a major threat yet.

So the verdict is that two-factor authentication is good. Turn it on if you can. Here’s some examples of where to look for these settings:

Facebook: Security settings / Login approvals.
Google: Accounts / Security / 2-step verification.
MS Hotmail/Live: Micosoft Account / Security info / Two-step verification.
WordPress: Settings / Security / Two Step Authentication.
Twitter: Not supported yet. :(

Safe surfing,

UPDATE: Twitter got their act together just hours after posting this article. Now they also provide two-factor authentication. Great! :)

UPDATE2: Seems like Twitter was in a rush to get two-factor authentication out. The implementation is still far from perfect. But it’s a step in the right direction. I’m sure they will get things right, let’s hope it doesn’t take too long.

More posts from this topic


A temporary profile picture but permanent app permissions

We are all sad about what’s happened in Paris last Friday. It’s said that the terrorist attacks have changed the world. That is no doubt true, and one aspect of that is how social media becomes more important in situations like this. Facebook has deployed two functions that help people deal with this kind of crisis. The Safety Check feature collects info about people in the area of a disaster, and if they are safe or not. This feature was initially created for natural disasters. Facebook received criticism for using it in Paris but not for the Beirut bombings a day earlier. It turned out that their explanation is quite good. Beirut made them think if the feature should be used for terror attacks as well, and they were ready to change the policy when Paris happened. The other feature lets you use a temporary profile picture with some appropriate overlay, the tricolor in this case. This is a nice and easy way to show sympathy. And it became popular very quickly, at least among my friends. The downside is however that it seemed so popular that those without a tricolor were sticking out. Some people started asking them why they aren’t supporting the victims in Paris? The whole thing has lost part of its meaning when it goes that far. We can’t know anymore who genuinely supports France and who changed the picture because of the social pressure. I changed my picture too. And it was interesting to see how the feature was implemented. The Facebook app for iOS 9 launched a wizard that let me make a picture with the tricolor overlay. Either by snapping a new selfie or using one of my previous profile pictures. I guess the latter is what most people want to do. But Facebook’s wizard requires permissions to use the camera and refuses to start until the user has given that permission. Even if you just want to modify an existing picture. Even more spooky. The wizard also asked for permission to use the microphone when I first run it. That is, needless to say, totally unnecessary when creating a profile picture. And Facebook has been accused of misusing audio data. It’s doubtful if they really do, but the only sure thing is that they don’t if you deny Facebook microphone access. But that was probably a temporary glitch, I was not able to reproduce the mic request when resetting everything and running the wizard again. Your new profile picture may be temporary, but any rights you grant the Facebook app are permanent. I’m not saying that this is a sinister plot to get more data about you, it may be just sloppy programming. But it is anyway an excellent reminder about how important the app permissions are. We should learn to become more critical when granting, or denying, rights like this. This is the case for any app, but especially Facebook as its whole business model is based on scooping up data about us users. Time for an app permission check. On your iOS device, go to Settings and Privacy. Here you can see the categories of info that an app can request. Go through them and think critically about if a certain app really needs its permissions to provide value to you. Check Facebook's camera and microphone permissions if you have used the temporary profile picture feature. And one last thing. Make it a habit to check the privacy settings now and then.   [caption id="attachment_8637" align="aligncenter" width="169"] This is how far you get unless you agree to grant Facebook camera access.[/caption]   [caption id="attachment_8638" align="aligncenter" width="169"] The Settings, Privacy page. Under each category you find the apps that have requested access, and can select if the request is granted or denied.[/caption]     Safe surfing, Micke   PS. The temporary profile picture function is BTW simpler in Facebook's web interface. You just see your current profile picture with the overlay. You can pan and zoom before saving. I like that approach much more.   Photo by Markus Nikander and iPhone screen captures    

November 16, 2015
facebook login

Using Facebook to log in – safe or not?

Open up your favorite web site and you can see what this is about right away. There are in many cases two options, an ordinary log-in and “Log in with Facebook”. Have you been using the Facebook option? It is quite convenient, isn’t it? I was talking to a journalist about privacy a while ago. One of the hints that ended up in the final story was that it isn’t necessary a good idea to link your other accounts to Facebook. And that raised questions. Some people have wondered why it is so, and pointed out that we at F-Secure also provide that option in our portal for F-Secure SAFE, MY SAFE. So let’s take a closer look. Is it good, bad or ugly? Here’s the important points: Facebook acts like an authentication service in this scenario. One single password opens the door to many services. This is indeed convenient and reduces the need to remember a lot of different passwords. But you should use different passwords on every service to reduce the damage if a password is leaked. That could happen for example in a phishing scam. Using Facebook’s log-in everywhere is putting all your eggs in the same basket. The worst thing you can do is to use the same user ID and password on all your sites, but *not* the Facebook function. A leak in any of them could give the attackers access to all your systems. Using the Facebook login instead is in this case a way to *improve* security. Facebook's servers are well secured, a leak from them is highly unlikely. It may reveal private info from Facebook to the other service unnecessarily. Most of us just click OK when Facebook asks for permission to give data to the other service, without thinking about what we really approve. Facebook will get yet another sensor to profile you. They will know that you use a certain service, when and how often you use it, and on what kind of device and where in the world you are when using it. Most people are on Facebook under their real name, but you may want to use other services more anonymously. If you don’t want it to be publicly known that you use a particular service, then you shouldn’t use your real-name Facebook account to log in. Remember that privacy on-line is not just about how much private data you reveal. It’s also very much about whom you reveal it to and how fragmented your digital footprint is. Preventing different services from consolidating your data improves your privacy. So should I use this feature at all? Maybe, it depends. There are some downsides, but it's a convenient way to log in, that can’t be denied. But first, the security-savvy approach is to instead use separate strong passwords on every site and a password manager. It’s a little bit of work when you set it up, but it is really the most secure approach. Don't use Facebook log-in for critical services. Those are sites containing sensitive information or where you make payments. They always deserve a strong unique password. But there's also a large number of sites that aren't that critical. Your on-line newspaper for example. If crooks get your Facebook password then your compromised newspaper account will be the smallest of your problems. Go ahead and use Facebook log-in for those if you find it convenient, but keep in mind the privacy concerns listed above. It's all about how picky you are about privacy. And don’t forget to review the permissions you have givens to apps and sites in Facebook. Go to Settings / Apps and you see the list of approved apps. Remove anything that sounds fishy, that you can’t remember approving or that you aren’t using frequently. Don’t be afraid to remove too much. The worst thing that can happen is that an app or site stops working and asks you to give it Facebook permissions again. Open all remaining apps and review what permissions they have. Think about what they do for you and if they really need all their permissions. Fix the permissions if needed. To wrap up. The Facebook log-in feature is not a security problem. Facebook's security system is solid and your security is not in jeopardy if you use it. But I still recommend separate passwords for the critical sites. The question marks are on the privacy front instead. Linking sites together contributes to forming a more comprehensive digital footprint. It's up to you to decide how worried you are about it. With this info you should be able to make an educated decision about where Facebook log-in can and can't be used.   [caption id="attachment_8629" align="aligncenter" width="266"] Jamendo's permissions in Facebook. This is the basic permissions most well-behaving apps/sites ask for. If the site asks for more, consider carefully if it really is needed.[/caption]   Safe surfing, Micke     Images by C_osett and Facebook screen capture

November 12, 2015

Are you using Facebook at work? (Poll)

I’m sure you have run into it if you work at a company with an organized IT function. They provide you with a computer, but they control it and set restrictions on what you can do with it. This is justified. Keeping the systems patched and updated is necessary to maintain security. Not to talk about maintenance of the anti-malware. But security is not the only driver for controlling the computers. Productivity is another. The web is usually wide open and employees can surf wherever they like. Entertainment, social media, news, hobbies, work-related issues, they are all there in the same web. Trying to limit web access to just work-related content is a really hard task. Practically impossible in most cases. And on top of that, you can always pull out your smartphone, if the mean IT-folks have created nasty restrictions on the employer-owned device. Employers’ worries about security and productivity are demonstrated in a Bloomberg article. It’s a bit dated already, but probably still quite accurate. The list of banned apps can be divided in three groups. Cloud services makes it easy to share company secrets. Entertainment is time-consuming and addictive. And finally Facebook representing social media. Banning Facebook is interesting. Social media has quickly grown to be one of our most commonly used communication platforms. Is it really fair to shut this off for the whole workday? But Facebook can on the other hand be very addictive. I’m sure there are employees who spend far too much time there. But the question is if an effective ban of Facebook really would improve productivity? No-one can work 8h flat out without any breaks. Personally I feel that micro-breaks, like checking Facebook, helps me stay focused and get the work done. So let’s see what you think. What’s your relation to Facebook at work time?   [polldaddy poll=9172266]   Safe surfing, Micke   Photo by momo  

November 10, 2015