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Debugging Android Native
Library
Omkar Naik & Palak Sethia
Venue: AMA, Ahmedabad

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Introduction and Agenda
● What is native library?
● JNI
● Analysis
● Static debugging
● Dynamic debugging
● How to efficiently debug?
● Task
● Requirements
● Demo Time!
2

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Native Library in android
● C/C++ Code
● Native Development Kit (NDK)
○ compiles the native code into native library
● Features
○ Performance
○ Security
3

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Android
Application
NDK
SDK
Java/Kotlin C/C++
JNI
4

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Java Native Interface
JNI C/C++
functions/Code
Java Classes/
Dalvik Code
JAVA/Kotli
n
Native
libraries
5

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Analysis
● Where to look for?
● Supported architectures
● Identification
static {
System.loadLibrary("lib");
}
OR
static {
System.load("lib/arm64-v8a/lib.so");
}
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Static debugging
● Code is not executed
● Understand the code logic using graphs,
decompilation etc
● Cannot read variable values
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#Dynamic
#Debugging
8

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● Execute code and try
● Check specific parts of code
● Runtime analysis of code flow and values
● Different tools used for runtime analysis
○ #IDA/Ghidra
○ #Frida
Dynamic Debugging Cont.
9

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How to efficiently debug?
● Identify the interesting code in static analysis
● Understand code logic with specific inputs and conditions while execution
● Execute functions which are hard to understand
● Set breakpoints and analyze variables values.
10

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TASK
● hpAndro Vulnerable Application
○ Backdoor 7 Task
● Identify Pin to get the flag
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Requirements
● IDA Pro
● Rooted android device
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● Task
● Apktool decompile
● Locate .so file for task
● .so file load in IDA
● Start IDA dbgsrv in android
● Decompile the function after identification
● Set debug points
● Start the task
DEMO TIME !
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Thank you