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Hack crypto secrets from heap memory to exploit Android application
Typically, There was no significant impact (in general the severity is low) for a Broken Cryptography flaw in the android application. Unless, if there is a strong dependency between the application workflow and cryptography functions.
In the recent private bugbounty program, I faced a challenge. In which the application request body was encrypted with some kind of cryptography mechanism. So I should have to find the encryption mechanism to further assess the application.
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To understand the encryption logic, I have de-compiled the APK using Android reverse Engineering tools set and then I have analyzed the code for the encryption mechanism and sensitive key information. But I haven’t found any hard-coded secret in the reversed source code.
It’s time to Inspect the application heap memory
Heap Memory
The Heap is used for dynamic memory allocation. To provide a smooth user experience, Android sets a hard limit on the heap size for each running application. The heap size limit varies among devices and is based on how much RAM a device has. Heap memory is used to allocate objects. Whenever you create an object, it’s always created in the heap.