Frida CLI Tools

Common errors

• SystemError: attach_to_process PTRACE_ATTACH failed: 1

  cause This error typically indicates insufficient permissions to attach to the target process, often due to security mechanisms (e.g., SELinux policies, Samsung Knox, Google Play Protect) or `ptrace` restrictions.
  fix Try running the command with elevated privileges (e.g., `sudo sysctl kernel.yama.ptrace_scope=0` on Linux, ensure Frida is properly signed on macOS, or disable security mechanisms like Magisk Hide/Knox on Android and reboot).

• ImportError: dynamic module does not define init function (init_frida)

  cause This error usually arises when trying to use `frida` Python bindings compiled for one Python major version (e.g., Python 2.x) with a different major version (e.g., Python 3.x), or vice versa.
  fix Ensure you are using the correct Python interpreter for the installed `frida` package. If you have multiple Python versions, verify your `pip` installation target and `PYTHONPATH`. It is recommended to use Python 3.7+ with recent Frida versions.

• Failed to enumerate applications: unable to perform ptrace pokedata: I/O error

  cause Often seen on Android devices, this indicates an issue with Frida's ability to interact with processes due to stringent security mechanisms like SELinux or other kernel-level protections.
  fix Attempt to disable relevant security mechanisms (e.g., Samsung Knox) via `adb shell` commands and reboot the device. For example: `adb shell pm disable-user --user 0 com.samsung.android.knox.attestation`.

• frida: command not found

  cause The `frida-tools` CLI executables are not in your system's PATH environment variable.
  fix On Linux/macOS, ensure your user's `~/.local/bin` is in PATH. On Windows, manually add the Python 'Scripts' directory to your system's PATH. Restart your terminal after modifying PATH.

Warnings

• breaking Frida 17 (released May 2025) introduced significant breaking changes in its JavaScript API, affecting static Module and Memory methods, and legacy enumeration APIs. For example, `Module.findBaseAddress()` and `Memory.readU32(ptr)` were removed.
  Fix: Migrate your JavaScript agents to use `Process.findModuleByName().base` for module base addresses and instance methods like `ptr.readU32()` for memory operations. Runtime bridges (Java, ObjC, Swift) are also no longer bundled directly with Frida's GumJS runtime but are baked into `frida-tools` REPL and `frida-trace` agents.
• gotcha Mismatch between `frida-tools` and `frida-server` versions on target devices can lead to unexpected behavior or failures. While `frida-tools` is installed on your host, `frida-server` runs on the target device.
  Fix: Always ensure that the `frida-server` version deployed on your target device (e.g., Android, iOS) matches the `frida` Python package version installed on your host system. Download the correct `frida-server` binary from Frida's GitHub releases page.
• gotcha On Windows, the `frida` and `frida-tools` CLI commands might not be found in the system PATH after installation, leading to 'command not found' errors.
  Fix: Manually add the Python 'Scripts' directory (e.g., `C:\Users\<username>\AppData\Local\Packages\PythonSoftwareFoundation.Python.<version>_qbz5n2kfra8p0\LocalCache\local-packages\Python<version>\Scripts`) to your system's PATH environment variable.
• gotcha When attaching to a process by name using `frida.attach('process_name')`, a `ValueError: ambiguous name` error can occur if multiple processes share the same name.
  Fix: Instead of the process name, use the Process ID (PID) which is unique. You can find the PID using `frida-ps -U` for USB devices or `frida-ps -a` for all processes. Example: `session = frida.attach(12345)`.

Install

• pip install frida-tools Install latest version

Imports

• frida

  import frida

  frida-tools provides CLI utilities, but its Python API relies on the 'frida' package for direct scripting.

Quickstart

This quickstart demonstrates how to use the underlying 'frida' Python binding (which 'frida-tools' uses) to attach to a running process, inject a JavaScript agent, call an RPC method, and process messages. Replace 'cat' with an actual running process on your system or a connected device for a successful execution. For mobile devices, ensure 'frida-server' is running on the device and specify the correct device and process.

import frida

def on_message(message, data):
    print(f"[on_message] message: {message}, data: {data}")

try:
    # Attach to a running process, replace 'cat' with a valid process name or PID on your system
    # For remote devices, use frida.get_usb_device().attach('process_name') or frida.get_device_manager().get_device('id').attach('process_name')
    session = frida.attach('cat') # Example: a simple running process
    
    # Create a JavaScript script to inject
    script = session.create_script("""
        rpc.exports.enumerateModules = () => {
            return Process.enumerateModules();
        };
    """)
    
    # Set up message handler
    script.on('message', on_message)
    
    # Load the script into the target process
    script.load()
    
    # Call an exported RPC method from Python
    modules = script.exports_sync.enumerate_modules()
    print([m['name'] for m in modules])
    
    # Keep the script running (or detach when done)
    input('[*] Press Enter to detach from process\n')
    session.detach()
except frida.ProcessNotFoundError:
    print("Error: Process 'cat' not found. Please ensure 'cat' or another process is running.")
except Exception as e:
    print(f"An error occurred: {e}")