Grindr’s Reset Token Weakness: A Complex Great Plunge

September 5, 2021 7:50 am Published by Leave your thoughts

Compensation sci and cyber protection

Dating programs keep a treasure trove of info about their consumers which will make these people an encouraging target for destructive actors.

On March 3, 2020, scientists ( Wassime Bouimadaghene who located the susceptability, and Troy look exactly who said they) launched they experienced discover a security alarm weakness within the dating software Grindr.

This vulnerability granted you to use the password reset hyperlink for a merchant account as long as they understood the users e-mail. The code reset web page would range from the password readjust token in a reaction to the customer, this reset token should simply be e-mailed for the consumer.

The drawing below shows exactly how this exchange hypothetically should happen.

When the email address contact info is distributed as A POST on the server so that they can readjust the code the servers is responsible for a good number of duties. The host will determine if consumer have a merchant account then creates a one-time utilize secure url with a reset token to be emailed with the customer.

Within safeguards vulnerability, the server’s impulse included in the body the reset token needed to access the code reset webpage. Because of the blend of the reset token and learning the type that Grindr uses to bring about their particular reset link, any customer could execute an account control.

The difficulty in this combat was minimal, and anyone who have access to the development apparatus for best web browser to consider benefit from this.

Recreating the problem

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Although leaking a reset token toward the customer try a straightforward mistake which is not hard to comprehend, I want to to see if I was able to reproduce an operating style of the problem and a remedy because of it. I started by setting up an express host and thought to use nedb for a lightweight database.

The next step in recreating this was to develop basic signup, and code readjust listings. The sign-up page inserts the user during the database for the soon after structure.

The type just isn’t as critical as various data I’m keeping to utilize after for generating the reset token. The code hash, creation hours, and _id which are familiar with make the reset token and can ensure it is single-use.


The password reset page is when the protection weakness in Grindr developed thus, making this just where I most certainly will copy exactly the same concern. In order start up we verified which email address contact info published client-side prevails through the data, when the individual shouldn’t exists I quickly send the message, ‘customer not just discovered’.

In the event the cellphone owner does indeed really exist however create something based upon the company’s code hash and the moment the user’s password am latest generated. The key is utilized to encrypt and decrypt the token, it needs to be distinctive per each customer in addition to special everytime the same consumer resets the company’s password. Utilising the hash together with the generation time period accomplishes this purpose.

The very last parts necessary for the JWT might be load, making use of user’s id, as well as their email address contact info this information might end up being decrypted eventually through the token and regularly check out anyone’s identity. The keepsake is produced with the aid of both payload as well as the secret after which can later become decrypted server-side by generating the secrets again.

After developed the JWT looks like this below, if you are not familiar with JWT I’d suggest checking this short article around.

The Token Leakage

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Generally after the email address contact info was submitted to the machine the processing would happen following the host would reply with many help and advice and tell the customer if perhaps the reset was successful or otherwise not. If prosperous you get the link to readjust their password via email. This link is made up of a reset token appended into reset URL.

In this situation like the Grindr readjust token problem, I responded back again to the customer straight during the responses torso utilizing the reset token and emailing the individual the hyperlink to readjust. Setting up the organization apparatus you’ll be able to read where keepsake is being released.

If a malicious professional received both the reset token and knew of a person’s email address you will find the direction they could combine the two items of records and gain access to the reset webpage. This allows any cellphone owner to readjust another users profile password without the need for accessibility their mail levels.

Reset Web Page Security

Why is the reset webpage secured are largely the JWT. There is not an alternative to make sure that you aside from by validating the reset token. That’s why this vital to protect the reset token precisely as it gets the recognition for a user.

The web link type I used for the reset backlink are and that’s easily regained by a malicious professional on your understanding of a message tackle along with reset token.

To confirm the person I’ve found the e-mail inside my collection and begin to confirm this by using the token critical information. Subsequently, replicate the secret using the same way previously and decode the token with the secret to achieve the cargo.

After i’ve the cargo i could operate the id stored in they evaluate up against the owner’s identification document stored in the website. If both ids go well with this suggests the cellphone owner was legitimate and that the keepsake hasn’t been tampered with.

As soon as the customers’ recognition is definitely proved a fundamental reset password version is distributed toward the clients which has had extra validation with the reset token.


The simplest way to repair this problem will be eliminate the reset token from your impulse during the reset website feedback looks, while nevertheless making certain that the client-side web browser receives the verification required for the reset inquire.

This looks easy with this type of a little example nevertheless the more technical the computer becomes the difficult it is to catch these slips.

Grindr luckily for us attached the blunder in a timely fashion and don’t assume that anyone used this susceptability. They’re setting up another insect bounty application to simply help counter these types of problems from existing in the wild for too long time period.

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This post was written by rattan

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