Mahmoud Gamal - Security Blogs

Hello hackers, A couple of weeks ago I tweeted about exploiting an out of band XXE vulnerability with a firewall blocking all outgoing requests including DNS lookups, so here is the full story: This is a private bug bounty program so I won't be mentioning who the vendor is. As usual during a hacking night while navigating the target application I came across an endpoint that took a parameter called xml but its value was encrypted. Later I found out that XML data sent to the backend is encrypted in the client side before sent in HTTP requests which means that XML data might not be properly validated in the backend, so I wanted to modify it to be able to inject my own XXE payload. So what I first tried was to find the JavaScript function used to encrypt the XML and do the same for my custom XML payload, however, the application's JavaScript was minimized with WebPack which made it very hard to read and trace functions. To avoid the hassle of finding the JavaScript encrypting...

TL;DR We found a zero-day within a JavaScript template library called handlebars and used it to get Remote Code Execution in the Shopify Return Magic app. The Story: In October 2018, Shopify organized the HackerOne event "H1-514" to which some specific researchers were invited and I was one of them. Some of the Shopify apps that were in scope included an application called "Return Magic" that would automate the whole return process when a customer wants to return a product that they already purchased through a Shopify store. Looking at the application, I found that it has a feature called Email WorkFlow where shop owners can customize the email message sent to users once they return a product. Users could use variables in their template such as {{order.number}} , {{email}} ..etc. I decided to test this feature for Server Side Template injection and entered {{this}} {{self}} then sent a test email to myself and the email had [object Object] within ...