I want to prevent users from voting more than one time in my website, I used two methods to do that, but no one do that well !!
using cookie.
the problem : users can delete the cookie and return to vote again and again ..
using database table.
The problem : users shouldn't forced to register in my website !
So, How i can solve this problem ?
You have your two answers, you need to decide which is best. No option is going to be bulletproof. It's all about slowing them down, and what level of effectiveness is acceptable for you.
A cookie is generally the acceptable way to do this. Yes, cookies can be cleared, but if the desire to prevent duplicate voting is that important, than registration is the only effective way to prevent it. Any other mechanism could probably be beaten by those that want to. You could use something like Evercookie, but I don't generally think it's a good practice to do so. If you make your registration process simple, but effective, some users will do that.
An IP address is just as flawed as most redisential IPs are not statically assigned. Someone could reset their modem, and get a new IP address. Or worse, someone could reset their modem, get an IP address that has already visited the site, and be unable to vote. Another scenario is users behind NAT. If 200 people are sharing an IP with NAT, then only one of them will be able to vote.
You could get creative with the IP address though. Keep using the cookie, because that will be effective. If you start detecting multiple votes from the same IP address (because they cleared their cookies), display a CAPTCHA. If it isn't someone trying to abuse the system, then they still get the opportunity to vote. This will help defeat automated voting, and slow down users enough that abusing your voting system isn't worth their time. This as well, can be defeated, it's what level of effectiveness is acceptable to you. Even registration isn't purely 100% effective, but probably the most effective. What would stop someone from registering many times with different email addresses?
I dont think you have many options as you are not forcing users to register. You need to use session or cookies. As pointed out in comments you can also check the IP Address. But if intended audience uses dynamic IP address assigned by their ISP, then this solution also failed.
If possible you can ask user to registered with their facebook/google id, like stackoverflow is doing
There isn't an infallible way to accomplish what you want from a web application and specially without requiring users to register.
This site (Stack Overflow) does it right, by registration. IP is a really bad idea because all the folks behind a proxy/server can't vote. Most folks have mulitiple browsers, you don't even need to delete the voting cookie to vote again, just use another browser. As mentioned, OpenID is the lowest impact + highest security route. They can get around that via multiple accounts.
Related
This question is not related to ASP.NET specifically, but more web applications in general.
I am building a web application wherein I am registering a user. As of now I am taking in very basic credentials like First Name, Last Name, etc of the user. In this website I am giving some information for free for any user who has just registered so that the user finds my website authentic and that it is not a fake website. After that, to get more information, the user has to pay.
The information my site provides will get obsolete after sometime. So, when a new user registers, he/she will get the new information that gets updated; but the old users have to pay to get the same new information.
My problem here is once the information gets obsolete the same person can re-register with a different set of credentials and get the new information. I want to avoid this from happening.
So my question here is this: what information should I request from the user, or extract from the user, to check that the same user is not re-registering? Or any other way to make this possible.
I am thinking of getting the IP address of the machine from which the person is registering and use it to check. But the user can use a different machine to re-register.
I am completely lost here and not getting the solution. I even checked on the Internet but could not find an answer.
Please let me know if you need any further information from my side.
You will not find a technical way to prevent users from registering multiple times. They can simply use another device, IP, another email account and different credentials.
What you can do is asking them to send you hard to fake "offline" information, like a credit card number or a photo of the ID. Some users may still be able to register multiple times this way, but probably not indefinitly. You will however lose many possible clients this way who are unwilling to provide such information for a test account, so this is likely not the solution you want.
My advice would be one of the following two:
Limit the information/service you give out to free users, so that even if they register again they will gain something when they pay.
Try to bind them to their account in a way where they would lose something if they threw it away. This may for example be providing user rewards for activity (real or virtual) or increasing their experience based on their history. Take SO for example: If you registered again, you would lose all your reputation. The users will think twice if this is worth the new content.
After reading all of the above, i think a good solution could be to let the user identify himself through facebook or linkedin. Few people will have a second account.
I think you cannot put any users like that because every thing can be duplicate
There are some ways for which the user must have payment mode or identity details like passport or it is windows application you can have finger scanner it will be definitely Unique..
You can do this (with limitations) with the use of cookies. Setting a cookie on the users device will allow you to determine who the visitor is and that they have already registered.
The limitations are that cookies can be deleted or blocked and are only valid for that specific user agent - the user could use a different device or a different browser on the same device. A lot of people don't really know about cookies though and how to delete them.
By tying this technique with a requirement to provide a valid email address you can make it a hassle for somebody to register more than once as they will have to create a new email account and then delete their cookies.
Whether this will stop enough people depends on your site and your requirements - if you're giving money away then this technique is not nearly good enough. If you just want to discourage the practice of multiple accounts it may be enough.
Your only way out is to have SOMETHING the existing user gets as a "gift?" or added value to maintain just one account. If you can identify items of value to your subscribers and offer to "give" it to them provided their account "attains" one or more status, then you'll get some control. Take stackoverflow.com for example, I don't need a second account.
Identifying by facebook or linkedin is a good option, but if you are giving such services. which are very beneficial for the users, so they dont mind on creating multiple accounts on even facebook or linked in.
So what i think is to set some reward type stuff with each user, and increase the services as they get increment in rewards.once they are good in rewards and are capable to use multiple services, this increases the probability that they will not create another account.
A friend of mine showed me a website recently where a person could vote for something. There was no login required, but when I tried to vote more than once (per day), the web site knew. What are possible ways for this to be done?
My first thought was IP address, but I don't think that would work. If I'm in a large office building, work, or public wifi (starbucks, airports, etc) wouldn't it be the case that only 1 person per shared IP address could vote?
What if I drove around the city voting with my phone. If the website were to simply log IPs, wouldn't I theoretically be able to vote once for every cell tower I was close to?
If cookies were used, wouldn't it be possible to disable cookies and vote infinitely?
What mechanism is used to create this type of behavior?
Almost certainly done with a cookie.
It probably tests first that cookies are enabled, and only then lets you vote.
Try voting twice using two different browswers.
I've seen the following Question : Implementing "Report this content" and detecting spammer or robot triggered event, but it doesn't quite answer all I need to know about setting up a "Report this content" function.
My situation is very similar (users not needing to login to be able to report content) but I'm unsure what I should capture about a user to ensure that they are not reporting a single posting multiple times.
I thought the most obvious one would be IP address but I heard that mobile users can sometimes find themselves all sharing a single IP address when the users are close together.
This means I need something else as well.
The Question above mentions user-agent but it doesn't sound too far fetched that multiple iPhone users could be sharing the same IP address, so even with IP address and user-agent it still isn't unique.
What if I logged their IP address and their session ID?
Would that be a good compromise or can anyone suggest a better option?
Thanks
I am building application that needs to interact with users without accounts and keep track of them. I know OpenID is great and easy and I've used it in almost all my apps, but accounts are not option even those that user is likely to have like Facebook, Google, Yahoo account, etc.
Any coding language is acceptable (but asp.net, JavaScript or Flash would be best, or a combination).
So my plan is to use cookies...but cookies are so easily removed (I really don't count it as reliable identifier)
IP address...well this is efficient even trough proxies, but if someone uses dynamic IP like my whole country this also becomes unreliable
Flash cookies are fine, but I recently read an article describing Mozilla Firefox History-cleaning system gets rid of them too, I need confirmation for this.
Browser Fingerprinting - I don't know how reliable it is since anyone that knows little of any language that can send HTTP requests can spoof it (client string at least).
If anyone knows of any other methods from the ones I listed, or want to correct me in my list feel free to reply.
So, the Web application I'm working on allows input from anonymous users (and their participation in the flagging system).
As for the spamming issue, would it be enough to use the honeypot method or is an image CAPTCHA (e.g. reCAPTCHA) necessary in this case?
For the flagging system, if I want to let anonymous users to "flag" posts, it's not enough to allow a flag (per post) per cookie because they have control over the cookies (and could bypass this prevention). I should allow ONLY a flag per IP then, right? I know that this method would prevent users that share the same IP (yeah, corporate networks, etc.) to flag to the same post, but there is no other way around it, is there?
How can I ensure anonymous users' anonymity? By this I mean, how to prevent their posts to be "tracked" (if this is even possible). I know that every server has a log of every connection, so, is it possible to hide theirs?
Any help would be greatly appreciated!
Honeypots are useless if your site is popular, because then people will write custom bots for it. For the flagging, you can limit it to one per cookie, and rate-limit it by IP. That way, people on corporate networks, etc. will be a little inconvenienced but not completely out of luck.
It's completely up to you what you log and how long you keep them. By default, the request IP may be logged, but you don't have to log it. Most sites do, but the real difference is how long they keep it.