What are the steps to hook into crypto functions using Frida for DeepSeek analysis

Step 1: Setting Up Frida

First, ensure that Frida is installed on your system. You can install Frida using pip for Python bindings:

bash
pip install frida-tools

Step 2: Preparing the Environment

1. Connect to the Device: Ensure your Android device is connected to your computer and USB debugging is enabled. You can verify this by running `adb devices` in your terminal.

2. Install Frida Server: Download and install the Frida server on your Android device. This can be done using `adb push` and `adb shell` commands.

Step 3: Identifying Crypto Functions

1. Static Analysis: Before hooking, perform static analysis of the DeepSeek app to identify potential crypto functions. This can involve decompiling the APK using tools like Apktool and inspecting the code for crypto-related classes or methods.

2. Identify Relevant Classes: Look for classes related to encryption, such as `javax.crypto.Cipher` for Android apps.

Step 4: Writing the Frida Hook

1. Create a Hook Script: Write a JavaScript script that Frida can use to hook into the identified crypto functions. For example, to hook `Cipher.init()` in Android, you can use the following script:

javascript
   if (Java.available) {
       Java.perform(function() {
           const Cipher = Java.use('javax.crypto.Cipher');
           Cipher.init.overload('int', 'java.security.Key').implementation = function (opmode, key) {
               console.log('[+] Entering Cipher.init()');
               console.log('[ ] opmode: ' + opmode);
               console.log('[ ] key: ' + key.toString());
               console.log('[-] Leaving Cipher.init()');
               this.init.overload('int', 'java.security.Key').call(this, opmode, key);
           }
       });
   }
   

2. Save the Script: Save this script to a file, for example, `cipher_hook.js`.

Step 5: Running Frida

1. Launch Frida: Use the Frida client to attach to the DeepSeek app process and run your hook script. The command might look something like this:

bash
   frida -U -l cipher_hook.js -f com.deepseek.app --no-pause
   

Replace `com.deepseek.app` with the actual package name of the DeepSeek app.

2. Monitor Output: Frida will output the hooked function calls to the console, providing details about the encryption operations, such as modes and keys used.

Step 6: Analyzing Results

1. Interpret the Output: Analyze the output to understand how encryption is implemented in the app. Look for potential vulnerabilities like hardcoded keys or weak encryption algorithms.

2. Refine the Hook: If necessary, refine your hook script to capture more specific information or to handle different encryption scenarios.

By following these steps, you can effectively use Frida to analyze and hook into crypto functions within the DeepSeek app, helping identify potential security vulnerabilities.

Citations:
[1] https://securityscorecard.com/blog/a-deep-peek-at-deepseek/
[2] https://fingerprint.com/blog/exploring-frida-dynamic-instrumentation-tool-kit/
[3] https://trustedsec.com/blog/mobile-hacking-using-frida-to-monitor-encryption
[4] https://www.nowsecure.com/blog/2025/02/06/nowsecure-uncovers-multiple-security-and-privacy-flaws-in-deepseek-ios-mobile-app/
[5] https://frida.re
[6] https://support.corellium.com/features/frida/using-frida-find-hooks
[7] https://www.nowsecure.com/blog/2023/10/04/debugging-mobile-apps-with-frida-a-developers-dream-toolkit/
[8] https://approov.io/blog/deepseek-apps-security-failures-how-approov-could-have-prevented-the-damage
[9] https://www.trellix.com/assets/docs/atr-library/tr-function-hooking-for-recon-and-exploitation.pdf