I have my little web application, with simple registration strategy - provide email and password and you are done.
Recently bot's starting to attack my application, registering big number of users from non existent emails using the same passwords.
I want to prevent that. My idea is to extend login verification, but check the existance of email address. Do you know any web services (prefereably WCF) that could do that?
This is definitely not the way to solve this problem. Try one of these
Allow user to enter only username and send auto-generated password to their email.
Send a verification link to the user email and approve him/her only after verification
This has been discussed on How to check if an email address exists without sending an email? . Basically there are ways verify email addresses, but in practice none of them is reliable. However, you can still check via SMTP, and if the server denies the existence of the expected user, send him an email with a verification link anyway. This does not prevent spammers from setting up fake servers that acknowledge the existence of any user, of using other peoples email addresses, but it's probably the closest you can get to your initial requirement of having no verification email.
I would recommend you to update your registration form. Try to use something tricky for bots. For example, post the form via AJAX with JSON object wrapper.
Try a service like: http://elasticemail.com/
You can use the api to check if the email was delivered. There is also a 'bouce list' you can check.
Related
I am new to firebase and I am trying to handle firebase user authentication in React.js. I did manage to create users with email and passwords. But, now I would like to send the user an Email link to reset their password.
My code currently look like this.
// This line of code belongs to the top
import { auth } from '../firebaseConfig'
//This part goes under the React component
<p onClick={async () => {
try{
await sendPasswordResetEmail(auth, // My Email Id)
alert('Password reset link has been sent to your email')
}
catch(err){
alert(err)
}
}}
>Forgot your Password ?</p>
However, I do not get any error messages and I do get the alert message that says "Password reset link has been sent to your email." Unfortunately, I didn't receive any email. Note that I have given my own email id as the parameter for testing purposes.
firebaser here
Did you check your spam folder? We recently see a lot of the emails from Firebase Authentication ending up in the user's spam folder or being marked as spam in a system along the way. This is being tracked in this status message on the Firebase dashboard and in public issue #253291461.
To reduce the chances of the messages getting marked as spam, consider taking more control of the email delivery yourself.
As a first step, consider using a custom domain with your project. Email that comes from a custom domain has less chance of being marked as span.
As a second step, consider setting up your own SMTP server.) for delivering the email, so that the emails are not being delivered from Firebase's shared infrastructure anymore.
While these steps are more involved, they typically will drastically reduce the cases where the messages from Firebase Authentication are marked as spam.
Full Guide Based on Frank's Answer
Firstly create a new email account you can use to relay the Firebase emails through the SMTP server with. I personally chose Gmail, but I tested with Outlook and it also works.
You can now find an SMTP server host that will work for your scenario. If you're sending less than 1000 emails per month you can find free and reliable hosts. I chose SMTP2GO's free option.
Now you've found the SMTP host, add the email address you've chosen as a single sender email (note that if you do own a domain, you can alternatively use that to send emails).
Note that you will have to verify the email, usually by your host sending a link to the email's inbox. Make sure to check spam.
Once verified, navigate to where you host allows you to add SMTP Users and add a new user. This will allocate an SMTP username and password.
Navigate to the Firebase console, and choose the Authentication option from the sidebar (within the Build product category).
Go to Templates → SMTP Settings and enter the details of your SMTP server. The username and password fields are to be filled with the SMTP user login you created in the step above.
It is better to use TLS, but I believe SSL should work too but it is untested.
Click save, and you're all set up - but there may still be steps to perform depending on your email provider.
Provider Specific Steps
If the emails are being sent to an account managed by Google you will have no issues with your emails being quarantined by anti-spam policies and it will work immediately.
If you are using Outlook, you will have a different problem on your hands. Outlook's built in defender will most likely have auto-quarantined your email under multiple policies - that bit is important.
These policies are likely to be both spam and phish policies. If you unblock one of them, the other will catch it and re-quarantine.
Unblock both policies for the email address, and test. You can see the status of quarantined messages in Microsoft 365 Defender app under Review → Quarantine. Please note that you will need to be an administrator to add global allow policies to your email accounts.
If this still doesn't work it is likely that your company has an additional external filter (as mine did), and you will have to add the IP's manually to the Tenant Allow/Block Lists spoofed senders tab.
I am working on a .NET application and I have set up an external login with facebook.
Currently, when the user uses the external login functionality, signs in to Facebook and my app recieves his email address, I create a new user account and consider the email address verified. (otherwise he could not login)
Is this a good practice though? Is it possible that some attacker would change the email address midway or something? What is the best practice for letting users sign in using external login providers?
Any help would be much appriciated, thanks.
Edit: In this tutorial the guy sends a confirmation email to the email address he recieves from the external login providers. However this seems impractical to me. It kind of defeats the purpuse of simplifying the log in/sign in process, moreover I don't think I was ever asked to confirm my email when I had used external login providers to log in myself.
Is it possible that some attacker would change the email address midway or something?
No, because you are using facebook which implements openid or oauth2.
In oauth2, mail and its password are safe because you do not manage them. Those are managed by your oauth2 provider (facebook in your case)
Also according to the oauth2 flow which is the same in google, facebook, linkedin, etc the provider don't send you the email. It sends you the authorization code:
use go to your web.com
user is redirected to https://www.facebook.com/v8.0/dialog/oauth?client_id={app_id}&redirect_uri={redirect_uri}
oauth2 provider prompts a login if user was not logged in previously
user accepts the consent form (next next)
oauth2 provider (facebook in your case) at the end, perform a final redirect to your web.com (using the callback url previously registered) sending the authorization code: https://web.com?code=196da272-083c
this code is required to generate the access_token and can be used just one time(another http invocation)
the access_token is required to get the email (another http invocation)
The only way to attack could be try to send fake authorization codes to https://web.com?code=**** but in the next step (exchange auth code for a new access_token), facebook will return you an error because the attacker cannot create real authorization codes.
Confirmation email
As you said, if your web allows the user to login with some social network, add a new step with email confirmation is impractical. Is more, facebook allows the use of phone number instead of mail.
But there are some scenarios (not in the authentication) in which mail could be your ally:
Offer an option for alert the user with something like this: Hi Bob, a new account was created with your social network... If you didn't, please click on the following...
confirm an email to be used in future notifications
I use createUserWithEmailAndPassword(string, string) in flutter, but I noticed if the user used a fake email address, like making us some random Gmail or yahoo account that doesn't exist, the user would still be registered, is there a solution to this
Or some logic that checks if the email account is real, then I can use the result in an if else statement to create the account
If you are looking for a solution that doesn't involve blocking the user experience, you'll be disappointed. We could come up with a new solution for checking whether an email exists or not, but this doesn't guarantee you anything. The user may use an existing email that doesn't belong to him/her.
The best you can do is send a verification email to your user, which is supported by Firebase. However, the user experience is going to be blocked until the user verifies the email.
Update
Check here how to send the user the verification email and here how to see if the email has been verified.
i was wondering if any one can advise me on how i can go about implementing a email and account validation feature in my ASP.net website. so when a user creates an account, an email is sent to the email address used, and the user needs to verify that email address to be able to logon.
thanks
Suggested workflow..
Create an account for the user in your database and mark the account as "to be validated"
Produce a random key, maybe a GUID and add it to the users account
Email the random key to the user along with a unique URL, e.g www.myurl.com/validateuser.aspx?userid=45532
To email using asp.net use the system.net.mail namespace - lots of bits on the internet about this.
On validateuser.aspx ask user to enter key sent to them in email.
Check if keys match. If so update db record to "validated"
Edit
By the way, there is a nice answer here on Stack Overflow if you are using forms auth
you can use regular expression of email id check after validation save id in database and and on button behind code of registration write code for sending email using system.net.mail
many email sending function available on internet.
after registeration using coding to check on logon either the email exists in ur database or not.
This is almost a year too late, but for the records you should use the built-in ASP.NET Membership functionality because you get all this (and much more) for free, no need to make e-mail validation logic if it's already made for you is it?
http://msdn.microsoft.com/en-us/library/yh26yfzy.aspx
net website, i would like to implement forget password. I am using following steps
Form having input box for login Id and email Id and CAPTCHA
when user enter details and submit, at backend after validation new password is generated and replaced old password at database.
New passowrd is send to user at email.
Please help me whether i am doing right or not?
Is there any other secure mechanism for the same?
[EDIT]
Thanks, i got your reply. Really this is a secure mechanism. But here i have few doubt
What message should i shown to user when he enter loginId and email address at forgotten password page?
Whether message would be same for valid user and mallicious user?
Advantage of using CSRF token? Any help / link
When user click on link then what should i do; because as i guess user should automatically loggin into their account -then after that i have 2 choice (first) send new password automatically to user (second) new form will shown to user where user will enetr old password and new password twice?
Please help?
I can see why you'd want a CAPTCHA, but I'd take a different approach.
When a password reset is requested check that a reset has not already been requested for that account within the last X minutes. If a password has already been requested ignore the reset request.
Check the IP requesting the password reset. If that IP has requested a password reset in the last Y minutes ignore the request.
If the checks in 1 & 2 pass check the account exists. If it doesn't ignore the request.
If we've gotten this far generate a one time token, which expires in Z minutes and a password reset URL which encompasses this token. Email this to the registered email address. When the URL is loaded prompt for a new password and reset.
For those who believe that you should tell the user where the email has gone I strongly disagree. This is "information leakage", even if you do limit it to the domain name. For example say I've registered on JeffAtwoodEatsBabies.com as blowdart. If Jeff had requested a password reset for me and you showed the registration domain then he'd see idunno.org. This is my personal domain and thus Jeff would know the blowdart user is, in fact, me. This is a bad bad thing. I should not have to register using hotmail or gmail or whatever in order to protect myself from your code showing an email domain to all and sundry.
In addition you shouldn't be showing error messages at all. No matter what happens, a username is not actually registered, or too many requests have been made or the sky has fallen you should be telling the user that the password reset procedure has started. Informing a user that an account doesn't exist is more information leakage.
One final thing you could do is add a CSRF token to the reset request page, so it cannot be driven from other web sites.
Followup
So to answer your further questions.
What message you show is up to you. "Instructions for resetting your password have been emailed to the registered email for this account" is one idea, but really it's down to your audience.
Already addressed above.
Wikipedia is a good starting point. How you do it depends on your platform and is a complete other question! For ASP.NET you could look at my codeplex project, http://anticsrf.codeplex.com or look at ViewStateUserKey.
When the link is clicked I would first validate the token in the URL against the username it's being applied to then I would either allow the user to enter a new password, or generate a new one and email it. You can't prompt for the old one, as the whole point is the user has forgotten it!
There are many ways this has been implemented. As you said, generating a new password and sending it to the registered email address is one method. I wouldn't suggest you go that route though, as my password would be reset everytime somebody tried guessing my password.
Instead, the best thing I've seen to date is simply emailing the registered email with a link that will begin a password reset process. You may even let the user know which email address to check by showing a masked version of their email address used in registration:
An email was sent to ********#hotmail.com. Please check your inbox to continue.
Be sure to keep in consideration those of us who may forget which email address were registered with - typically a few security questions are a great way to make that information available.
I've done that recently. When the user enters their username or email address, we generate a unique token and email it to them as part of a link. Upon receipt of that email, they click the link, and are automatically logged in, taken to the my account screen, and prompted to reset their password.
Of course, this relies 100% on the security of the email client, but it's hard to beat from a usability perspective.
You shoud check the answer to the question : Can anyone provide references for implementing web application self password reset mechanisms properly? from D.W. on security.stackexchange.
It is the most complete answer I found on the subject. I also suggest you to read this article : Everything you ever wanted to know about building a secure password reset feature