How do services/platforms uniquely identify users? - security

If you log into a platform (Twitch, Blizzard, Steam, Most Crypto exchanges, Most Banks) from a new device you'll typically get an email stating so.
As far as my knowledge goes, the only information you can get on a request is
IP address
Device Operating system & version
Browser type & version
Are these platforms basing their "unique" users off of this information alone and/or am is there more information that can be gathered?

From a security perspective the largest thing is your identity or how you authenticate. That's king. The email stating "hey this is a new device" I've seen handled differently from site to site. Most commonly it's actually browser cache and I see banks specifically use browser cache to store these kinds of tokens. Otherwise every time your cellphone connected to a new cell tower you'd likely be flagged as different. They're not necessarily the same as an authentication token, rather it just says hey I've authenticated as this user to this site before. Since it's generated by the service provider, the service provider knows to trust it, and it's nearly impossible to hack (assuming it's implemented correctly).
From my own experience the operating systems and browser types, that's more record keeping than actionable insights, however you could build a security system that takes into account an IP address from very different geo-locations. I.e. why is this guy from the US logging in from China. They just logged in from California 3 hours ago, this is impossible. I don't believe most sites really go to that extent though. I do see MFA providers saying "hey there's a login from china, do you want to approve?". That workflow makes a lot more sense.
The last part of your question is tricky, regarding "unique users." Most calculate that based off the number of sessions opened (tabs), or in the case of Twitch (since you mentioned them specifically), the number of tabs that are streaming that video in. These open platforms where anyone without an account can stream the content obviously treat this differently than say Netflix that makes you authenticate and each account has a limited number of sessions that can be open.

AFAIK, most of the systems like this stores a cookie in your browser when you log (not the session cookie, just a random ID) that is also assiciated to your account in the provider database, so when you came back, you log in, and they check whether you have that cookie set and in case if the ID matches
They you can probably do some more advance stuff with that ID, like base that value from the browser, OS, expire date and so on

Related

How should signup form error responses be displayed

I have a subscription based application that is build using MERN. I've recently submitted the application to be security tested and one of the responses that I received was that the application should not specifically tell the user why their signup application has been rejected for all cases. For example, if they enter a username or email that has already been registered, I shouldn't return an error message that says "Sorry, this username is already registered", as this would allow the user to build a list of users and emails that have registered with our site.
I understand why we need to prevent this, but I don't understand how I can tell the user why there signup submission failed without telling them that it's because that email has already been registered. It seems pointless to reject their signup form without giving them a specific reason, does anyone know what the best thing to do here is?
I have a subscription based application that is build using MERN
The fact you're using MongoDB, Express, React and NodeJS is irrelevant to how your end-users and visitors use your product.
I've recently submitted the application to be security tested...
Watch out - most "security consultants" I've come across that offer to do "analysis" just run some commodity scripts and vulnerability scanners against a website and then lightly touch-up the generated reports to make them look hand-written.
one of the responses that I received was that the application should not specifically tell the user why their signup application has been rejected for all cases
Hnnnng - not in "all" cases, yes - but unfortunately usability and security tend to be opposite ends of a seesaw that you need to carefully balance.
If you're a non-expert or otherwise inexperienced, I'd ask your security-consultant for an exhaustive list of those cases where they consider harmful information-disclosure is possible and then you should run that list by your UX team (and your legal team) to have them weigh-in.
I'll add (if not stress) that the web-application security scene is full of security-theatre and cargo-cult-programming practices, and bad and outdated advice sticks around in peoples' heads for too long (e.g. remember how everyone used to insist on changing your password every ~90 days? not anymore: it turns out that due to human-factors reasons that changing passwords frequently is often less secure).
For example, if they enter a username or email that has already been registered, I shouldn't return an error message that says "Sorry, this username is already registered", as this would allow the user to build a list of users and emails that have registered with our site.
Before considering any specific scenarios, first consider the nature of your web-application and your threat-model and ask yourself if the damage to the end user-experience is justified by the security gains, or even if there's any actual security gained at all.
For example, and using that issue specifically (i.e. not informing users on the registration page if a username and/or e-mail address is already in-use), I'd argue that for a public Internet website with a general-audience that usernames (i.e. login-names, screen-names, etc) are not particularly sensitive, and they're usually mutable, so there is no real end-user harm by disclosing if a username is already taken or not.
...but the existence or details of an e-mail address in your user-accounts database generally should not be disclosed to unauthenticated visitors. However, I don't think this is really possible to hide from visitors: if someone completes your registration form with completely valid data (excepting an already-in-use e-mail address) and the website rejects the registration attempt with a vague or completely useless error message then a novice user is going to be frustrated and give-up (and think your website is just broken), while a malicious user (with even a basic knowledge of how web-applications work) is going to instantly know it's because the e-mail address is in-use because it will work when they submit a different e-mail address - ergo: you haven't actually gained any security benefit while simultaneously losing business because your registration process is made painfully difficult.
However, consider alternative approaches:
One possible alternative approach for this problem specifically is to make it appear that the registration was successful, but to not let the malicious user in until they verify the e-mail address via emailed link (which they won't be able to do if it isn't their address), and if it is just a novice-user who is already registered and didn't realise it then just send them an email reminding them of that fact. This approach might be preferable on a social-media site where it's important to not disclose anything relating to any other users' PII - but this approach probably wouldn't be appropriate for a line-of-business system.
Another alternative approach: don't have your own registration system: just use OIDC and let users authenticate and register via Google, Facebook, Apple, etc. This also saves your users from having to remember another password.
As for the risk of information-harvesting: I appreciate that bots that brute-force large amounts of form-submissions sounds like a good match for never revealing information, a better solution is to just add a CAPTCHA and to rate-limit clients (both by limiting total requests-per-hour as well as adding artificial delays to user registration processing (e.g. humans generally don't care if a registration form POST takes 500ms or 1500ms, but that 1000ms difference will drastically affect bots.
In all my time building web-applications, I've never encountered any serious attempts at information-harvesting via automated registration form or login form submissions: it's always just marketing spam, and adding a CAPTCHA (even without rate-limiting) was all that was needed to put an end to that.
(The "non-serious" attempts at information-harvesting that I have seen were things like non-technical human-users manually "brute-forcing" themselves by typing through their keyboard: they all give-up after a few dozen attempts).
I understand why we need to prevent this, but I don't understand how I can tell the user why there signup submission failed without telling them that it's because that email has already been registered. It seems pointless to reject their signup form without giving them a specific reason, does anyone know what the best thing to do here is?
I'm getting the feeling maybe you got scammed by your security "consultants" making-up overstated risks in their report to you - rather than your web-application actually being at risk of being exploited.

Preventing registered users from sharing passwords

Below is a proposal for dealing with a situation of website security. I am wondering whether it seems feasible, from both a technical and usability point of view. I want to make sure that the proposal does contain any glaring errors.
A. THE WEBSITE
The website in question is a school website where students may purchase various items. These students get an account on the website with a username and password, which they can use to login. Once they login, they have access to protected pages with private content which are unavailable to the public at large.
B. THE SECURITY CONCERN
The owners of the website wish to prevent a situation where a single student signs up on the website, obtains a username and password, and then circulates those credentials to a circle of friends who are then able to login to the website and illegally view the private content.
C. THE SOLUTION
The central idea we have come up with to deal with this security problem is to permit each student to login to the website on two devices only. Once a student logs in on two different devices, they are restricted to those two devices. If they then attempt to login on a third device, the system would simply not permit them to do so. It is our understanding that other websites offering private content, such as Netflix, use such an approach.
D. IMPLEMENTATION
Two ideas come to mind to implement the above security measure: a. IP address. b. Cookies. We rule out IP addresses, which can change, and choose cookies. Websites such as amazon.com allow their customers to login once, and then whenever they return to the website, they are always recognized. This is almost certainly achieved through cookies.
Thus each time a student logs in, we will store on their device a cookie. And we will also store this cookie in our database under that student's account. Thus each time a student logs in on any device, we will check whether the device they are currently logging in on contains the cookie we have stored for that student. If it does not, we will know that the student is logging in on a different device. We will thus be able to know how many devices the student is trying to login on.
E. DRAWBACKS
We have identified at least three possible drawbacks to this approach:
Clearing Cookies. People can, for a variety of reasons, choose to clear the cookies from their computer.
A bona fide person may occasionally not have access to their usual device, and wish to login on a different computer.
People do purchase new devices from time to time.
These are examples of situations where a bona fide user, for legitimate reasons, wishes to login, but will be unable to, due to the website's security restriction of two devices.
We have some ideas as to how to build logic into the system to deal with such situations, which we may implement in the future, but for the time being, we feel that such situations are sufficiently rare that we do not need to handle them programmatically.
Rather, for now, in the event that a student is locked out, they will get a screen with a message explaining why we have not allowed them into the system, and a button which they can click on which will automatically generate an email to the site administrators.
The email will inform them that a student wishes to login on a third device. The administators can then contact the student, and, if they are satisfied that the need is bona fide, they will be able to take steps from the CMS to allow that student in.
The size of the student body is sufficiently manageable that the above approach should be feasible.
F. FAIR WARNING
We will inform the students of these security measures when their account is activated, in order to prevent unpleasant surprises.
This is a typical example of trying to fix via IT a real-world policy problem; in this case, forbidding students to share their credentials.
The solution you are proposing limits usability (for the reasons which you already listed under Drawbacks) and does not ensure security because cookies - and especially content - can be copied around. In short, it is feasible, but can easily be circumvented. It's up to you to decide whether it is worth to implement it. It would probably be better to enforce the "no sharing credentials" rule e.g. set up random checks and send any student caught violating the rule to the Dean.

How to reliably detect if a user is connecting to a site with a new device?

I have a requirement where an email (or SMS) verification to be obtained whenever a registered user logs into a site using a new device/browser, similar to what Salesforce is doing.
Goal is to reduce the chance of user account being misused by someone, but at the same time it should not become an nuisance to the users.
What are the reliable mechanisms to detect if a request is coming from a new device?
One way would be to use the IPAddress, but that would cause issues when someone's internet connection gets a dynamic IP, and with mobile devices which will get new IPs as they move to new places.
Has the advantage of all browsers on that device (FF/Chrome/IE) are authorized with single confirmation.
Other way is to use a persistent cookie (without sliding expiration), downside is confirmation will have to be repeated for different browsers. (Not a huge issue though, as it's unlikely scenario).
Third option is some kind of hybrid solution of the above two.
My question is, are there accepted mechanisms to do this? What are the reliable ways to detect if someone is using a new device to connect to the site (doesn't have to be bullet-proof though)? Any other advice?
I'd go with the Cookie.
IP addresses are often shared. There's not really a way to identify their computer other than via the browser on the web.
The cookie value should include the username and an HMAC of the username (and probably a nonce too).
After user registers or logs in successfully, send the device cookie. If they are trying to login without a device cookie, they probably haven't used that browser before.

How to Check for Shared Accounts

We have an application that includes a voting component.
To try and minimise voter fraud we allow N number of votes from the same IP address within a specific period. If this limit is hit we ignore the IP address for a while.
The issue with this approach is if a group of people from a school or similar vote they quickly hit the number. Their voting can also occur very quickly (e.g. a user in the class asks his classmates to vote which causes a large number in a short period).
We can look to set a cookie on the user's computer to help determine if they are sharing accounts or check the user agent string and use that too.
Apart from tracking by IP, what other strategies do people use to determine if a user is a legitimate or a shared account when the actual IP is shared?
If your goal is to prevent cheating in on-line voting, the answer is: you can't, unless you use something like SSL client certificates (cumbersome).
Some techniques to make it harder would be using some kind of one time token sent trough e-mail or SMS. Every smart kid knows how to cheat control cookies using privacy mode of modern web browsers.

What is a simple and secure way to transmit a login key from one website to another while redirecting a user?

I want to create a portal website for log-in, news and user management. And another web site for a web app that the portal redirects to after login.
One of my goals is to be able to host the portal and web-app on different servers. The portal would transmit the user's id to the web-app, once the user had successfully logged in and been redirected to the web app. But I don't want people to be able to just bypass the login, or access other users accounts, by transmitting user ids straight to the web app.
My first thought is to transmit the user id encrypted as a post variable or query string value. Using some kind of public/private key scenario, and adding a DateTime stamp to key to make it vary everytime.
But I haven't done this kind of thing before, so I'm wondering if there aren't better ways to do this.
(I could potentially communicate via database, by having the portal store the user id with a key in a database and passing that key to the web app which uses it to get the user id from that database. But that seems crazy.)
Can anyone give a way to do this or advice? Or is this a bad idea all-together?
Thanks for your time.
Basically, you are asking for a single-sign-on solution. What you describe sounds a lot like SAML, although SAML is a bit more advanced ;-)
It depends on how secure you want this entire thing to be. Generating an encrypted token with embedded timestamp still leaves you open to spoofing - if somebody steals the token (i.e. through a network sniffing) he will be able to submit his own request with the stolen token. Depending on the time to live you will give your token this time can be limited, but a determined hacker will be able to do this. Besides you cannot make time to live to small - you will be rejecting valid requests.
Another approach is to generate "use once" tokens. This is 'bullet proof' in terms of spoofing, but it requires coordination among all the servers within the server farm servicing your app, so that if one of them processed the token the other ones would reject it.
To make it really secure for the failover scenarios, etc. it would require some additional steps, so it all boils down to how secure you need it to be and how much you want to invest in building it up
I suggest looking at SAML
PGP would work but it might get slow on a high-traffic site
One thing I've done in the past is used a shared secret method. Some token that only myself and the other website operator knows concatenated to something identifying the user (like their user name), then hash that with a checksum algorithm such as SHA256 (you can use MD5 or SHA1 which usually are more available but they are much easier to break)
The other end should do the same thing as above. Take the passed identifying information and checksum it. Compare that to the passed checksum, if they match the login is valid.
For added security you could also concat the date or some other rotating key. Helps to run SSL on both sides as well.
In general, the answer resides somewhere in SHA256 / MD5 / SHA1 plus shared secret based on human actually has to think. If there is money somewhere, we may assume there are no limits to what some persons will do - I ran with [ a person ] in High School for a few months to observe what those ilks will do in practice. After a few months, I learned not to be running with those kind. Tediously avoiding work, suddenly at 4 AM on Saturday Morning the level of effort and analytical functioning could only be described as "Expertise" ( note capitalization ) There has to be a solution else sites like Google and this one would not stand the chance of a dandelion in lightning bolt.
There is a study in the mathematical works of cryptography whereby an institution ( with reputable goals ) can issue information - digital cash - that can exist on the open wire but does not reveal any information. Who would break them? My experience with [ person ]
shows that it is a study in socialization, depends on who you want to run with. What's the defense against sniffers if the code is already available more easily just using a browser?
<form type="hidden" value="myreallysecretid">
vis a vis
<form type="hidden" value="weoi938389wiwdfu0789we394">
So which one is valuable against attack? Neither, if someone wants to snag some Snake Oil from you, maybe you get the 2:59 am phone call that begins: "I'm an investor, we sunk thousands into your website. I just got a call from our security pro ....." all you can do to prepare for that moment is use established, known tools like SHA - of which the 256 variety is the acknowledged "next thing" - and have trace controls such that the security pro can put in on insurance and bonding.
Let alone trying to find one who knows how those tools work, their first line of defense is not talking to you ... then they have their own literature - they will want you to use their tools.
Then you don't get to code anything.

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