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110 lines
7.3 KiB
Markdown
110 lines
7.3 KiB
Markdown
# Exploiting a debuggeable application
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{% hint style="success" %}
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Learn & practice AWS Hacking:<img src="/.gitbook/assets/arte.png" alt="" data-size="line">[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)<img src="/.gitbook/assets/arte.png" alt="" data-size="line">\
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Learn & practice GCP Hacking: <img src="/.gitbook/assets/grte.png" alt="" data-size="line">[**HackTricks Training GCP Red Team Expert (GRTE)**<img src="/.gitbook/assets/grte.png" alt="" data-size="line">](https://training.hacktricks.xyz/courses/grte)
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<details>
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<summary>Support HackTricks</summary>
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* Check the [**subscription plans**](https://github.com/sponsors/carlospolop)!
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* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** us on **Twitter** 🐦 [**@hacktricks\_live**](https://twitter.com/hacktricks\_live)**.**
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* **Share hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
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</details>
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{% endhint %}
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# **Bypassing root and debuggeable checks**
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This section of the post is a summary from the post [**https://medium.com/@shubhamsonani/hacking-with-precision-bypass-techniques-via-debugger-in-android-apps-27fd562b2cc0**](https://medium.com/@shubhamsonani/hacking-with-precision-bypass-techniques-via-debugger-in-android-apps-27fd562b2cc0)
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## Steps to Make an Android App Debuggable and Bypass Checks
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### **Making the App Debuggable**
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Content based on https://medium.com/@shubhamsonani/hacking-with-precision-bypass-techniques-via-debugger-in-android-apps-27fd562b2cc0
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1. **Decompile the APK:**
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- Utilize the APK-GUI tool for decompiling the APK.
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- In the _android-manifest_ file, insert `android:debuggable=true` to enable debugging mode.
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- Recompile, sign, and zipalign the modified application.
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2. **Install the Modified Application:**
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- Use the command: `adb install <application_name>`.
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3. **Retrieve the Package Name:**
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- Execute `adb shell pm list packages –3` to list third-party applications and find the package name.
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4. **Set the App to Await Debugger Connection:**
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- Command: `adb shell am setup-debug-app –w <package_name>`.
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- **Note:** This command must be run each time before starting the application to ensure it waits for the debugger.
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- For persistence, use `adb shell am setup-debug-app –w -–persistent <package_name>`.
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- To remove all flags, use `adb shell am clear-debug-app <package_name>`.
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5. **Prepare for Debugging in Android Studio:**
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- Navigate in Android Studio to _File -> Open Profile or APK_.
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- Open the recompiled APK.
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6. **Set Breakpoints in Key Java Files:**
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- Place breakpoints in `MainActivity.java` (specifically in the `onCreate` method), `b.java`, and `ContextWrapper.java`.
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### **Bypassing Checks**
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The application, at certain points, will verify if it is debuggable and will also check for binaries indicating a rooted device. The debugger can be used to modify app info, unset the debuggable bit, and alter the names of searched binaries to bypass these checks.
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For the debuggable check:
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1. **Modify Flag Settings:**
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- In the debugger console's variable section, navigate to: `this mLoadedAPK -> mApplicationInfo -> flags = 814267974`.
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- **Note:** The binary representation of `flags = 814267974` is `11000011100111011110`, indicating that the "Flag_debuggable" is active.
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These steps collectively ensure that the application can be debugged and that certain security checks can be bypassed using the debugger, facilitating a more in-depth analysis or modification of the application's behavior.
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Step 2 involves changing a flag value to 814267972, which is represented in binary as 110000101101000000100010100.
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# **Exploiting a Vulnerability**
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A demonstration was provided using a vulnerable application containing a button and a textview. Initially, the application displays "Crack Me". The aim is to alter the message from "Try Again" to "Hacked" at runtime, without modifying the source code.
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## **Checking for Vulnerability**
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- The application was decompiled using `apktool` to access the `AndroidManifest.xml` file.
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- The presence of `android_debuggable="true"` in the AndroidManifest.xml indicates the application is debuggable and susceptible to exploitation.
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- It's worth noting that `apktool` is employed solely to check the debuggable status without altering any code.
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## **Preparing the Setup**
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- The process involved initiating an emulator, installing the vulnerable application, and using `adb jdwp` to identify Dalvik VM ports that are listening.
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- The JDWP (Java Debug Wire Protocol) allows debugging of an application running in a VM by exposing a unique port.
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- Port forwarding was necessary for remote debugging, followed by attaching JDB to the target application.
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## **Injecting Code at Runtime**
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- The exploitation was carried out by setting breakpoints and controlling the application flow.
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- Commands like `classes` and `methods <class_name>` were used to uncover the application’s structure.
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- A breakpoint was set at the `onClick` method, and its execution was controlled.
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- The `locals`, `next`, and `set` commands were utilized to inspect and modify local variables, particularly changing the "Try Again" message to "Hacked".
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- The modified code was executed using the `run` command, successfully altering the application’s output in real-time.
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This example demonstrated how the behavior of a debuggable application can be manipulated, highlighting the potential for more complex exploits like gaining shell access on the device in the application's context.
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## References
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* [https://medium.com/@shubhamsonani/hacking-with-precision-bypass-techniques-via-debugger-in-android-apps-27fd562b2cc0](https://medium.com/@shubhamsonani/hacking-with-precision-bypass-techniques-via-debugger-in-android-apps-27fd562b2cc0)
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* [https://resources.infosecinstitute.com/android-hacking-security-part-6-exploiting-debuggable-android-applications](https://resources.infosecinstitute.com/android-hacking-security-part-6-exploiting-debuggable-android-applications)
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{% hint style="success" %}
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Learn & practice AWS Hacking:<img src="/.gitbook/assets/arte.png" alt="" data-size="line">[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)<img src="/.gitbook/assets/arte.png" alt="" data-size="line">\
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Learn & practice GCP Hacking: <img src="/.gitbook/assets/grte.png" alt="" data-size="line">[**HackTricks Training GCP Red Team Expert (GRTE)**<img src="/.gitbook/assets/grte.png" alt="" data-size="line">](https://training.hacktricks.xyz/courses/grte)
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<details>
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<summary>Support HackTricks</summary>
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* Check the [**subscription plans**](https://github.com/sponsors/carlospolop)!
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* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** us on **Twitter** 🐦 [**@hacktricks\_live**](https://twitter.com/hacktricks\_live)**.**
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* **Share hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
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</details>
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{% endhint %}
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