# iOS Frida Configuration

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## Installing Frida

**Steps to install Frida on a Jailbroken device:**

1. Open Cydia/Sileo app.
2. Navigate to Manage -> Sources -> Edit -> Add.
3. Enter "https://build.frida.re" as the URL.
4. Go to the newly added Frida source.
5. Install the Frida package.

If you are using **Corellium** you will need to download the Frida release from [https://github.com/frida/frida/releases](https://github.com/frida/frida/releases) (`frida-gadget-[yourversion]-ios-universal.dylib.gz`) and unpack and copy to the dylib location Frida asks for, e.g.: `/Users/[youruser]/.cache/frida/gadget-ios.dylib`

After installed, you can use in your PC the command **`frida-ls-devices`** and check that the device appears (your PC needs to be able to access it).\
Execute also **`frida-ps -Uia`** to check the running processes of the phone.

## Frida without Jailbroken device & without patching the app

Check this blog post about how to use Frida in non-jailbroken devices without patching the app: [https://mrbypass.medium.com/unlocking-potential-exploring-frida-objection-on-non-jailbroken-devices-without-application-ed0367a84f07](https://mrbypass.medium.com/unlocking-potential-exploring-frida-objection-on-non-jailbroken-devices-without-application-ed0367a84f07)

## Frida Client Installation

Install **frida tools**:

```bash
pip install frida-tools
pip install frida
```

With the Frida server installed and the device running and connected, **check** if the client is **working**:

```bash
frida-ls-devices  # List devices
frida-ps -Uia     # Get running processes
```

## Frida Trace

```bash
# Functions
## Trace all functions with the word "log" in their name
frida-trace -U <program> -i "*log*"
frida-trace -U <program> -i "*log*" | swift demangle # Demangle names

# Objective-C
## Trace all methods of all classes
frida-trace -U <program> -m "*[* *]"

## Trace all methods with the word "authentication" from classes that start with "NE"
frida-trace -U <program> -m "*[NE* *authentication*]"

# Plug-In
## To hook a plugin that is momentarely executed prepare Frida indicating the ID of the Plugin binary
frida-trace -U -W <if-plugin-bin> -m '*[* *]'
```

### Get all classes and methods

- Auto complete: Just execute `frida -U <program>`

<figure><img src="../../images/image (1159).png" alt=""><figcaption></figcaption></figure>

- Get **all** available **classes** (filter by string)

```javascript:/tmp/script.js
// frida -U <program> -l /tmp/script.js

var filterClass = "filterstring"

if (ObjC.available) {
  for (var className in ObjC.classes) {
    if (ObjC.classes.hasOwnProperty(className)) {
      if (!filterClass || className.includes(filterClass)) {
        console.log(className)
      }
    }
  }
} else {
  console.log("Objective-C runtime is not available.")
}
```

- Get **all** **methods** of a **class** (filter by string)

```javascript:/tmp/script.js
// frida -U <program> -l /tmp/script.js

var specificClass = "YourClassName"
var filterMethod = "filtermethod"

if (ObjC.available) {
  if (ObjC.classes.hasOwnProperty(specificClass)) {
    var methods = ObjC.classes[specificClass].$ownMethods
    for (var i = 0; i < methods.length; i++) {
      if (!filterMethod || methods[i].includes(filterClass)) {
        console.log(specificClass + ": " + methods[i])
      }
    }
  } else {
    console.log("Class not found.")
  }
} else {
  console.log("Objective-C runtime is not available.")
}
```

- **Call a function**

```javascript
// Find the address of the function to call
const func_addr = Module.findExportByName("<Prog Name>", "<Func Name>")
// Declare the function to call
const func = new NativeFunction(
  func_addr,
  "void",
  ["pointer", "pointer", "pointer"],
  {}
)

var arg0 = null

// In this case to call this function we need to intercept a call to it to copy arg0
Interceptor.attach(wg_log_addr, {
  onEnter: function (args) {
    arg0 = new NativePointer(args[0])
  },
})

// Wait untill a call to the func occurs
while (!arg0) {
  Thread.sleep(1)
  console.log("waiting for ptr")
}

var arg1 = Memory.allocUtf8String("arg1")
var txt = Memory.allocUtf8String("Some text for arg2")
wg_log(arg0, arg1, txt)

console.log("loaded")
```

## Frida Fuzzing

### Frida Stalker

[From the docs](https://frida.re/docs/stalker/): Stalker is Frida’s code **tracing engine**. It allows threads to be **followed**, **capturing** every function, **every block**, even every instruction which is executed.

You have an example implementing Frida Stalker in [https://github.com/poxyran/misc/blob/master/frida-stalker-example.py](https://github.com/poxyran/misc/blob/master/frida-stalker-example.py)

This is another example to attach Frida Stalker every time a function is called:

```javascript
console.log("loading")
const wg_log_addr = Module.findExportByName("<Program>", "<function_name>")
const wg_log = new NativeFunction(
  wg_log_addr,
  "void",
  ["pointer", "pointer", "pointer"],
  {}
)

Interceptor.attach(wg_log_addr, {
  onEnter: function (args) {
    console.log(`logging the following message: ${args[2].readCString()}`)

    Stalker.follow({
      events: {
        // only collect coverage for newly encountered blocks
        compile: true,
      },
      onReceive: function (events) {
        const bbs = Stalker.parse(events, {
          stringify: false,
          annotate: false,
        })
        console.log(
          "Stalker trace of write_msg_to_log: \n" +
            bbs.flat().map(DebugSymbol.fromAddress).join("\n")
        )
      },
    })
  },
  onLeave: function (retval) {
    Stalker.unfollow()
    Stalker.flush() // this is important to get all events
  },
})
```

> [!CAUTION]
> This is interesting from debugging purposes but for fuzzing, to be constantly **`.follow()`** and **`.unfollow()`** is very inefficient.

## [Fpicker](https://github.com/ttdennis/fpicker)

[**fpicker**](https://github.com/ttdennis/fpicker) is a **Frida-based fuzzing suite** that offers a variety of fuzzing modes for in-process fuzzing, such as an AFL++ mode or a passive tracing mode. It should run on all platforms that are supported by Frida.

- [**Install fpicker**](https://github.com/ttdennis/fpicker#requirements-and-installation) **& radamsa**

```bash
# Get fpicker
git clone https://github.com/ttdennis/fpicker
cd fpicker

# Get Frida core devkit and prepare fpicker
wget https://github.com/frida/frida/releases/download/16.1.4/frida-core-devkit-16.1.4-[yourOS]-[yourarchitecture].tar.xz
# e.g. https://github.com/frida/frida/releases/download/16.1.4/frida-core-devkit-16.1.4-macos-arm64.tar.xz
tar -xf ./*tar.xz
cp libfrida-core.a libfrida-core-[yourOS].a #libfrida-core-macos.a

# Install fpicker
make fpicker-[yourOS] # fpicker-macos
# This generates ./fpicker

# Install radamsa (fuzzer generator)
brew install radamsa
```

- **Prepare the FS:**

```bash
# From inside fpicker clone
mkdir -p examples/wg-log # Where the fuzzing script will be
mkdir -p examples/wg-log/out # For code coverage and crashes
mkdir -p examples/wg-log/in # For starting inputs

# Create at least 1 input for the fuzzer
echo Hello World > examples/wg-log/in/0
```

- **Fuzzer script** (`examples/wg-log/myfuzzer.js`):

```javascript:examples/wg-log/myfuzzer.js
// Import the fuzzer base class
import { Fuzzer } from "../../harness/fuzzer.js"

class WGLogFuzzer extends Fuzzer {
  constructor() {
    console.log("WGLogFuzzer constructor called")

    // Get and declare the function we are going to fuzz
    var wg_log_addr = Module.findExportByName(
      "<Program name>",
      "<func name to fuzz>"
    )
    var wg_log_func = new NativeFunction(
      wg_log_addr,
      "void",
      ["pointer", "pointer", "pointer"],
      {}
    )

    // Initialize the object
    super("<Program nane>", wg_log_addr, wg_log_func)
    this.wg_log_addr = wg_log_addr // We cannot use "this" before calling "super"

    console.log("WGLogFuzzer in the middle")

    // Prepare the second argument to pass to the fuzz function
    this.tag = Memory.allocUtf8String("arg2")

    // Get the first argument we need to pass from a call to the functino we want to fuzz
    var wg_log_global_ptr = null
    console.log(this.wg_log_addr)
    Interceptor.attach(this.wg_log_addr, {
      onEnter: function (args) {
        console.log("Entering in the function to get the first argument")
        wg_log_global_ptr = new NativePointer(args[0])
      },
    })

    while (!wg_log_global_ptr) {
      Thread.sleep(1)
    }
    this.wg_log_global_ptr = wg_log_global_ptr
    console.log("WGLogFuzzer prepare ended")
  }

  // This function is called by the fuzzer with the first argument being a pointer into memory
  // where the payload is stored and the second the length of the input.
  fuzz(payload, len) {
    // Get a pointer to payload being a valid C string (with a null byte at the end)
    var payload_cstring = payload.readCString(len)
    this.payload = Memory.allocUtf8String(payload_cstring)

    // Debug and fuzz
    this.debug_log(this.payload, len)
    // Pass the 2 first arguments we know the function needs and finally the payload to fuzz
    this.target_function(this.wg_log_global_ptr, this.tag, this.payload)
  }
}

const f = new WGLogFuzzer()
rpc.exports.fuzzer = f
```

- **Compile** the fuzzer:

```bash
# From inside fpicker clone
## Compile from "myfuzzer.js" to "harness.js"
frida-compile examples/wg-log/myfuzzer.js -o harness.js
```

- Call fuzzer **`fpicker`** using **`radamsa`**:

```bash
# Indicate fpicker to fuzz a program with the harness.js script and which folders to use
fpicker -v --fuzzer-mode active -e attach -p <Program to fuzz> -D usb -o examples/wg-log/out/ -i examples/wg-log/in/ -f harness.js --standalone-mutator cmd --mutator-command "radamsa"
# You can find code coverage and crashes in examples/wg-log/out/
```

> [!CAUTION]
> In this case we **aren't restarting the app or restoring the state** after each payload. So, if Frida finds a **crash** the **next inputs** after that payload might also **crash the app** (because the app is in a unstable state) even if the **input shouldn't crash** the app.
>
> Moreover, Frida will hook into exception signals of iOS, so when **Frida finds a crash**, probably an **iOS crash reports won't be generated**.
>
> To prevent this, for example, we could restart the app after each Frida crash.

### Logs & Crashes

You can check the **macOS console** or the **`log`** cli to check macOS logs.\
You can check also the logs from iOS using **`idevicesyslog`**.\
Some logs will omit information adding **`<private>`**. To show all the info you need to install some profile from [https://developer.apple.com/bug-reporting/profiles-and-logs/](https://developer.apple.com/bug-reporting/profiles-and-logs/) to enable that private info.

If you don't know what to do:

```sh
vim /Library/Preferences/Logging/com.apple.system.logging.plist
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
        <key>Enable-Private-Data</key>
        <true/>
</dict>
</plist>

killall -9 logd
```

You can check the crashes in:

- **iOS**
  - Settings → Privacy → Analytics & Improvements → Analytics Data
  - `/private/var/mobile/Library/Logs/CrashReporter/`
- **macOS**:
  - `/Library/Logs/DiagnosticReports/`
  - `~/Library/Logs/DiagnosticReports`

> [!WARNING]
> iOS only stores 25 crashes of the same app, so you need to clean that or iOS will stop creating crashes.

## Frida Android Tutorials

{{#ref}}
../android-app-pentesting/frida-tutorial/
{{#endref}}

## References

- [https://www.briskinfosec.com/blogs/blogsdetail/Getting-Started-with-Frida](https://www.briskinfosec.com/blogs/blogsdetail/Getting-Started-with-Frida)


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