بِسْمِ اللَّـهِ الرَّحْمَـٰنِ الرَّحِيمِ
My name is Ahmad Halabi. I work as a Senior Cyber Security Specialist in UAE. I also do some Bug Bounty Hunting when I have a Free Time. You can check my Biography here: https://ahmadhalabi.net/biography/ .
After I saw that Apple started paying for Impactful Web Application Vulnerabilities, I decided to spend couple of hours hacking Apple, And yes I was able to find some cool bugs.
In this article, I will be disclosing one of my favorite bugs that I found in Apple. Enjoy Reading ^_^
Finding my Target ::
When you come across a big Asset like Apple or Microsoft, you have to know from where to start and what to check. For me I was looking for a target that is considered an important asset to Apple and contains valuable private information so the bounty will be worthy.
I found an interesting website which is https://applepaysupplies.com/.
Apple Pay Supplies: allows you to order Apple related Kits such as `Apple Pay Decals Kit` and `Apple Pay Signage Kit`.
Studying the Application Structure ::
I started checking the target website as a normal user who wants to order a kit. I turned on Burp Suite to intercept all the traffic of this website, then I proceeded with the order and navigated to `Place Order`.
After that I filled my Shipping Information and submitted my order.
Shipping Information includes: Full name, Company, Address information (Country, City, Street, Zip code) and Phone Number.
There is tracking order feature so after submitting your order you can track it.
To track your order, you have to put your email address and the order number that is assigned once the order is created.
I noticed here two interesting variables that need to be investigated further which are
Order Number and
Identifying the Vulnerability :: Chaining IDOR with Rate Limit discloses Shipping Information.
Submit button to track the Order Status, The page showed me Order details and I noticed this URL in the browser tab:
Here I thought about an IDOR vulnerability chained with Rate Limit mechanism to guess the
order_id of an Apple user who I already know his email ID.
So I started analyzing the
APP1162306 by generating multiple Orders and comparing their
APPcharacters are fixed.
- We have 7 numbers after
APPwhich can be brute forced.
I navigated to the target URL https://applepaysupplies.com/trackorder?order_id=APP1162306firstname.lastname@example.org&language_id=1 but the surprised thing was that it showed a blank page other than the Order Details response that was shown after hitting the
I was not able to do the attack by hitting
After some Recon and Analysis, I found an API that interacts with the backend to fetch the Order Information.
This API Request is responsible for Fetching the Order Status Details.
Now it was easy to proceed by generating 7 numbers wordlist and brute forcing the Order number in order to get the Valid Order Status Details.
Luckily there was no Rate Limit Protection in place so I was able to brute force the Order Number of any valid Apple User and I will disclose his Shipping Address Information.
- I made a detailed PoC and Reported this Vulnerability to Apple.
- After a while, Apple Fixed the Vulnerability and Requested me to check the Fix.
Checking The Fix ::
Apple fixed the Vulnerability by removing the API call responsible for fetching the Order Status Details (/api/Home/GetOrderStatus). So now users can only use the main Functionality which is Track Order.
Instead of the removed API endpoint, they used the Track Order request (https://applepaysupplies.com/trackorder?order_id=APP1162306email@example.com) to fetch the status details.
But they did some enhancement to this Track Order Functionality. They used CryptoJS Library to encrypt the values since now they are being sent and fetched from the Client Side.
So I had to check the Application carefully again and analyze the new changes deployed in addition to the new Encryption added.
Bypassing The Fix ::
I was checking the website again. I already know the main endpoint to track orders (https://applepaysupplies.com/trackorder) that accepts GET request with the following parameters:
order_id that stands for the Order Number and
I started analyzing the Request.
Using Burp Suite, I tried sending a GET request to the target URL:
but the response was not showing the Order Status nor Shipping details of this valid order.
This was a protection done by Apple End when they Fixed my old bug. So I was unable to use Intruder to brute force `Order Number` as I did in the previous bug with the API Endpoint.
I started analyzing the Client Side Behavior.
I opened the request (https://applepaysupplies.com/trackorder?order_id=APP1162306firstname.lastname@example.org) in the browser.
I noticed that there is a delay in showing the order details. It takes 1–2 seconds after loading to show the order details.
This behavior explained why I was not able to see the shipping details on the request level in Burp Suite.
CryptoJS to encrypt the
Order Number once requesting an order status. By this technique, Apple made it hard to brute force the Order Number.
I analyzed how the Encryption is done in the Application, and with the help of my Friend Max (h1 Profile), We wrote a script to encrypt the needed values using CryptoJS library as the Application did and brute force the Order Number.
With the advantage of the absence of Rate Limit protection against this GET endpoint, I was able to brute force the Order Number successfully and disclose the Shipping Information Again.
- Apple requested me to send the Bypass Details in a New Report since the Old Fix is Successful and the Vulnerability is now found in a different Endpoint.
- Apple confirmed the Vulnerability And Rewarded me the first half of the Bounty.
- Apple Took some time to implement a new Fix.
Confirming the Fix ::
Apple kept the Crypto JS Library in place, They just enhanced and increased the Encryption Level to make it harder to break.
Apple didn’t implement a Rate Limit Protection, but they Increased the Length of the Order Number.
Before, the Order Number was made up of: APP + 7 numbers.
Now, the Order Number is made up of: APP + 28 Characters & Numbers.
Brute Forcing 28 Random Characters is unfeasible even if you were able to decrypt their Encryption.
So I saw that the Vulnerability is Well Fixed and Reported back to Them.
Apple decided to reward me in Total $10,000 for the Main Vulnerability and the Bypass. My highest bounty so Far.
Apple is a great Bug Bounty Program with Big Scope. The only problem is that they are Late in Operation (Need time to investigate / Fix). But it is worth spending time on it because it is highly rewardable if you find an Interesting Vulnerability.