I am blocking a huge number of bots, except the ones from search engines, and then only allowing 2seconds of session management.
However, spam bots are still able to by-pass these measure and create a huge number of requests which is 'killing' the server.
I have read other articles on this site but none seem to directly answer this issue.
A bot probably behaves faster than a human. You could time how long it takes them to fill out the form. Anything less than a second or two is a bot.
A bot probably doesn't have JavaScript turned on. You could use that to your advantage.
You could hide a link via css (or not give it any text) that takes the bot to a bot.cfm page, which could then set a session value.
There are some open source projects but I can't remember the names of them off the top of my head.
CF10 has a new validation function.
Ben Nadel has written some useful posts in his blog regarding spiders/bots.
http://www.bennadel.com/blog/1083-ColdFusion-Session-Management-And-Spiders-Bots.htm
http://www.bennadel.com/blog/154-ColdFusion-Session-Management-Revisited-User-vs-Spider-III.htm
For forms, I use <cfimage> to create a captcha image. I have found that stuffing the captcha phrase in a session variable can cause problems (I can't remember what the problems were though). So, I now use <cfencrypt> to include an encrypted phrase in the form itself. The action page decrypts the phrase and compares it to what the user put in the captcha form field.
I've found CFSPAMProtect to be very useful at blocking automated form fillers.
It bases its SPAM/HAM test on an aggregate score of a number metrics including time on page, mouse movement (via JS) as well as the classic hidden form fields that shouldn't be filled in (but are filled in by dumb robots).
You can assign your own weightings and monitor the SPAM catch via email to allow you to tailor things.
It can work on its own or link to some third party SPAM tools such as Akismet.
So far I've found that it's good enough on it's own.
It's a custom tag and easy to implement in existing forms too which is nice.
Give it a go...
Related
I built an app for work that keeps track of client medications.
Although of course I did not include any client data when I deployed the app in order to be able to demonstrate it to employers, in the dropdown fields you can still see the initials of the clients.
I'm putting it in maintenance mode in between showing it, and I also added a bunch of fake records so that you can only see the real initials mixed in with other random initials (and again, only under the fields in the automatically generated dropdown menus, not in the actual data saved to the database). Since there's no other information about the clients, I think that's pretty much all I really need to do.
But all of this begs a more programmatic solution: how do I edit the previous values that Flask-WTF remembers so that you cannot see them in the dropdown?
Here is what I mean:
Please let me know what options I have!
Thank you.
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I am currently building a registration page where if the user leaves, I want to pop up a CSS box asking him if he is sure or not. I can accomplish this feat using confirm boxes, but the client says that they are too ugly. I've tried using unload and beforeunload, but both cannot stop the page from being redirected. Using those to events, I return false, so maybe there's a way to cancel other than returning false?
Another solution that I've had was redirecting them to another page that has my popup, but the problem with that is that if they do want to leave the page, and it wasn't a mistake, they lose the page they were originally trying to go to. If I was a user, that would irritate me.
The last solution was real popup window. The only thing I don't like about that is that the main winow will have their destination page while the pop will have my page. In my opinion it looks disjoint. On top of that, I'd be worried about popup blockers.
Just to add to everyones comments. I understand that it is irritating to prevent users from exiting the page, and in my opinion it should not be done. Right now I am using a confirm box at this point. What happens is that it's not actually "preventing" the user from leaving, what the client actually wants to do is make a suggestion if the user is having doubts about registering. If the user is halfway through the registraiton process and leaves for some reason, the client wants to offer the user a free coupon to a seminar (this client is selling seminars) to hopefully persuade the user to register. The client is under the impression that since the user is already on the form, he is thinking of registering, and therefore maybe a seminar of what he is registering for would be the final push to get the user to register. Ideally I don't have to prevent the user from leaving, what would be just as good, and in my opinion better is if I can pause the unload process. Maybe a sleep command? I don't really have to keep the user on the page because either way they will be leaving to go to a different page.
Also, as people have stated, this is a terriable title, so if someone knows a better one, I'd really appreciate it if they could change the title to something no so spammer inviting.
As soon as I saw the words "prevent the user" I started to wail in agony. Never prevent the user, only help them.
If they see your registration page and run off, that's their choice. Pop up a javascript confirm box if they've already filled in some data (because they might be navigating away accidentally) but leave it at that. If they haven't touched the form, leave them alone - they don't want to fill in your form.
Look at other methods of engaging users. If your form is huge and scary, break it into simple manageable chunks or better yet, simplify things so much that the user only gives you data when you need it. For example, you might not need their address until you want to post something to them.
By breaking it into multiple parts you can hook them with a simple form and once they've invested that time, they'll be more likely to continue the process.
But don't harass users. If they don't want to register, pestering them with pop-ups and jaavscript dialogues will just chase them off the site completely.
With that in mind, assuming you're just trying to stop people half-filling-in forms, there are a couple of options to genuinely help people:
Detect if the form has changed and ask them a simple confirm() message.
This is all you can do. A CSS "pop-in" just won't work because you can't control* the window location in the unload event.
*You can put an event listener on all your page's links to fire off something to check the form, but this only helps if the user clicks on one of those links. It won't help if, for example, the user clicks back or closes the window. You could do both CSS and javascript but you end up with a bit of a mess.
Persist the state of the form behind the scenes.
An extension to #1. Instead of squabbling with the user, let them go where they want but save the content of the form either to session or cookie (if it'll fit) and put something on the page (like SO's orange prompt bars at the top of the page) that reminds them that they've started filling in a form and gives them a link back to the form.
When they click that link, you load the data out of the cookie (or session) back into the form and let them carry on. This has the clear benefit of letting them do what they like on your site and keeps the data safe.. ish.
If they don't come back and their cookie/session expire, that's their fault. You can only lead a horse to water. It's not your job to force it to drink.
Don't do it.
But if you want, try this. Record mouse positions and detect a quick upward thrust -- the user is reaching for the BIG X or the top left or top right. Now might be your chance for an unobtrusive box in the screen.
I've seen this implement on the web and it is evil.
If you want to trap links, you could rewrite the links in the page to go to a "you really want to leave?" javascript function, passing the destination URL as an argument.
If you wanna keep users from using their "Back" button, or keep them from putting another URL in the address bar, stop. Stop now. (1) Browsers were made to prevent exactly that kind of obnoxious behavior, and (2) Even if they allowed it, see the last two words of (1). It's freaking rude. Your site is not that special, no matter how cool you think it is.
window.onbeforeunload = function() { return "Message"; };
Use a JavaScript like this to display a leave confirmation message.
Here are just a couple of approaches I could think of but they are not without flaw:
Whatcha Gonna Do technique
Detect the mouse position going towards the edges of the browser as the user might be going to close the tab, window, go back, navigate elsewhere among other things. If so, immediately prompt them that that may be a mistake and they are going to lose out on something very valuable. However, the catch here is that you don't know for sure what their intentions were and you might piss them off with that popup. Also, they might use a bunch of shortcuts such as Ctrl+W etc to do the same.
You've Got Mail technique
If you've managed to get hold of the user's email address before they closed the page, you've hit a jackpot. As soon as the user types anything into the email box and then leaves it, immediately send it to the server using AJAX. Save the state of the page into localStorage or on the server using a cookie or something so it can be recreated later. Every couple of hours send them an email giving them a direct link to the previously saved form, and maybe with special offers this time.
History Repeats Itself technique
Then there's the infamous history manipulation where you keep stacking the current page into the document history so the back button renders effectively worthless.
Don't Put All Your Eggs In One Basket technique
Another technique off the top of my head is to create multiple windows in the background with the registration form and keep them all in sync when any the fields in any one changes. This is a classical technique and really puts the "don't put all your eggs in one basket" saying into real-life usage.
Another advantage of this awesome technique is even if the user closes one of the windows, and later comes across an identical cloned window with all the fields they filled up-to-date populated, they might get confused and think that they never closed the page. And guess what, this time they might just go ahead and fill out the registration form. But you have to be cautious with this as anything more than 2 or 3 clones will make it obvious as to what's going on.
You're Winner technique
Another technique is to tell every user they they are the Xth visitor on the site and use a good rounded number for X such as 1000, 10000, 50000, etc. Tell them that they can claim their prize once they register on the site. Imagine how special each user feels when they land on your site. The prize doesn't have to be anything tangible, it can simply be free coupons that you find on the intertubes.
Where Do You Want To Go Today? technique 1
This is basically a rip-off of your answer. Use document.location.href = 'some url' inside your onbeforeunload callback to navigate to a different page before it is unloaded.
1 Firefox only.
Note: there is no silver bullet solution here unless you write your own browser with your own security policies, but these are all optimizations that you can do to make it utterly impossible for users to leave.
Not all browsers support a modal popup, without which your page would go ahead and navigate anyway.
This is real awful requirement. The sort of requirement that is reasonable in a desktop application but entire unreasonable feature of a web site. Imagine being unable to leave a website.
The answer is either use the horrible confirm box and lump it. Or don't ask the user to enter too much data per page. Use a step by step wizard style data entry, the loss due to accidental navigation is minimised.
You can change the Value of the url using document.location.href = "www.website.com"
I can accomplish this feat using confirm boxes, but the client says that they are too ugly.
If the problem is the ugliness of the standard JS popup boxes, try something like this: http://www.sohtanaka.com/web-design/inline-modal-window-w-css-and-jquery/
Apart from that I second what most people are saying: do this with extreme caution if you don't want to lose users.
I'm writing an classified ads website, I need that the users renew the Ads only clicking in a URL that I will send by email. What cautions should I have implementing a system like this? I've searched on the web but didn't find examples of an implementation like this.
Can someone give some clues about the right path to do this?
Best Regards,
First off, SQL Injection will be a major thing to worry about, especially when using obvious get parameters.
Second, you will want non-personally identifying info in the GET parameters. You will NOT want short ids such as 123456 as these are VERY EASILY guessed. A GUID (example 412dc535-03dd-4887-b702-02c8b85e8891, you would remove the - of course) is great for this.
Third, you will want some sort of basic verification that it is in fact the user that originated the request. Have each email have its own ID for the one click action, perhaps a GUID (long string of random characters), and make them expire after some time (a few days). Keep track of each email link separately and what they're supposed to do, so that someone couldn't just figure out the ID of someone's ad and keep running it over and over.
~Christian
I am running ColdFusion MX, so I don't have the possibility of using the built-in cfimage Captcha functionality in my application, before form submitting.
But the problem is without captcha the bots submit the forms.
What will be best way to prevent automatic submitting?
Captchas don't have to be images!
Try one of the following solutions:
Most bots don't understand CSS. Create two submit buttons, the first with a value that will be rejected by the server, the second with a value that will be accepted by the server. Hide the first one using CSS.
Ask the user to answer a simple math problem. This will require you to create the math problem and store the expected solution somewhere (like the user's session), then compare the user's submitted answer with the stored answer. For extra protection, you can create simple addition, subtraction and multiplication questions. Avoid division, remainders are a pain for some users.
Bots read the names of form elements, and tend to ignore text labels. Try creating a checkbox named "optout" (like a newsletter), checked by default. Next to the checkbox, ask the user to uncheck the checkbox if they are a human. The opposite technique also works (unchecked checkbox that you ask the user to check).
All of these solutions can be done without third party code or API calls.
That being said, reCAPTCHA is pretty good and easy to integrate into almost any environment.
Take a look at cfformprotect - it will work with CFMX 6 and all later engines.
It aims to be fully accessible - and invisible to most users - with an assortment of methods to stop bots and spammers.
Also you might want to look at a CF wrapper for reCaptcha, which is compatible with CFMX 7.
A technique I used with a different technology was to use image buttons. Your POST handler gets the x,y co-ordinates where the images were clicked. I found the bots (which are just generating post requests) were passing 0,0 and by dropping those requests on the floor I brought the spam posts down to less than the real ones. Sorry that I don't know how to do that in CF but I hope the technique is useful to you.
Its always a good idea to do data validation on the server side before processing no matter which solution you use.
This post may help: http://www.bennadel.com/blog/405-Fully-Accessible-Spam-Form-Submission-Blocking-Using-ColdFusion-And-X-HTML-Version-III-.htm
How about using calculation method? Just like 8 + 5 = ?
OR
how about using ColdFusion.Ajax.submitForm?
I'm building a website using Ubuntu, Apache, and Django. I'd like to block people from filling out and submitting a particular form on my site more than once. I know it's pretty much impossible to block a determined user from changing his IP address, deleting his cookies, and so on; all I'm looking for is something that will deter the casual user from re-submitting.
It seems to me that blocking multiple form submissions from the same IP address is the best way to achieve what I'm looking for. However, I'm unsure how I should do this, and whether I should be doing this from Apache or from Django. Any tips?
Edit: I'm looking to prevent intentional re-submission, not just unintentional double submission. e.g. I have a survey that I want to discourage people from voting multiple times on.
If your main concern is to prevent someone writes a script and automatically submit the form many times, you may want to use CAPTCHA with your form.
Several whole countries are NAT'ed, and some (most?) large multinational corporations too, many with several hundred thousand users each. Blocking anything by IP is a bad idea.
Go for a cookie instead, which is as good as it's going to get. You could also make the user login in, in which case you'd know if the form was submitted repeatedly for that login.
I would use the session id, and store form submissions in a table with session id, timestamp, and optionally some sort of form identifier. Then, when a form is submitted, you could check the table to make sure that it had not happened within a certain period of time.
Filtering on IP address and/or cookies are both easy to get around, but they will prevent the casual user from accidentally submitting the same stuff multiple times due to browser hick-ups, impatience and so on.
If you want something better than that you could implement login, but of course that prevents a lot of users from responding.
Add to the form a monotonically increasing id number in a hidden field.
As each form is submitted, record the id in a "used" list/map (or mark it used, or whatever, implementation detail).
If you get the same id a second time (if it's already in your used map) inform the user they double-submitted.
While nothing is fool proof, I would suggest something like this: When a user loads the page with your form on, a cookie is set and the value of the cookie is appended with a fixed secret string and the md5 value of this is written to a hidden field on the form. Ensure that a new value is generated each time the user access the form.
When the user submits the form, you check that the cookie value and form value match, that the cookie the user was given has not been used to submit the form before and that the referrer id match the URL of the form. Optionally you make sure that there has been no attempts to post from that IP in the last 2 minutes (fast enough that it wont matter to most people, but slow enough to slow down bots).
To fix this the user has to make a script that loads the page, store the cookies and submit the correct values. This is much more difficult than if the user could just submit the form.
Added Based on edit: I would block the users in the Django framework. This allows you to present a much better error message to the user and you only block them from that form.
This is a question of authentication and authorisation, which are related but not the same. In order to manage authorisation you must first authenticate (reliably identify) the user.
If you want to make this resist intentional misuse then you are going to end up with not only usernames and passwords but demands for information that personally identifies your users, along the lines of the stuff a bank asks for when you want to open an account. The bleeding hearts and lefties will snivel endlessly about invasion of privacy but in fact you are doing exactly the same as a bank and for exactly the same reasons.
It's a lot of work and may be affected by law. Do you really want to do it?
The following methods are all relatively simple, both to implement and to hack around. Anyone with Firebug and a little knowledge won't even blink.
The following JavaScript uses Mootools, and I haven't checked it to be bug free. I understand that JQ syntax is almost identical, and raw JS is similar enough, so the point should be clear.
1) If the form is being submitted via AJAX, you can check before submitting (sorry if I'm just stating the obvious).
var sent = 0;
$('myForm').addEvent('submit', function(){
if(!sent) this.send();
})
This is really simple, and surprisingly effective until they reload the page.
2) Add a JavaScript cookie. Again, with Mootools:
$('myForm').addEvent('submit', function(){
if(Cookie.read('submitted')){ alert('once only'); return false;}
else{ Cookie.write('submitted', 1); return true; }
})
This will work even if the user reloads the page.
3) Add a Python session cookie. I am not familiar with Python, but if it is like PHP, this will have no advantage over method 2. In either case, the user can delete the cookie with FireCookie or WebDeveloper Toolbar (or their equiv's on other browsers) and reload the page.
4) Add a Flash cookie (use Flex). This is ideal - Flash cookies are stored in a different location, are not obvious, and are very difficult to remove. The only downside is that you need to create and embed a tiny swf.
5) Store a value in a hidden field, and check for the value.
A hash can be added to the internal links to insure that the value remains filled in even if the page is navigated away from.
6) Other games can be played incrementing a URL (or a custom URL using htaccess) for each visitor.
An swf cookie is the best idea of the above, though it can be combined with the others.