amfidont

Description

A macOS utility that attaches to amfid with LLDB and bypasses app signature validation for explicitly allowed binaries. Allowed targets are matched by executable path prefix and/or cdhash.

Requirements

• SIP configuration that allows debugging system processes by either:
  • fully disable SIP
  • disable only debugging restrictions (csrutil enable --without debug)

Installation

xcrun python3 -m pip install -U amfidont

Usage

Usage: amfidont [OPTIONS] COMMAND [ARGS]...

A simple utility for bypassing amfid signature verification

Options:
  --path, -p TEXT      path of executable to allow (can be specified multiple times, merged with ~/.amfidont/paths)
  --cdhash, -c TEXT    cdhash of executable to allow (can be specified multiple times, merged with ~/.amfidont/cdhashes)
  --verbose, -v        enable verbose output
  --allow-all          allow all validations to pass
  --spoof-apple, -S    patch isApple to return true for allowed binaries
  --install-completion Install completion for the current shell.
  --show-completion    Show completion for the current shell, to copy it or customize the installation.
  --help               Show this message and exit.

Commands:
  daemon        Start amfidont in daemon mode.
  add-path      Add an allowed path prefix to persistent configuration.
  remove-path   Remove an allowed path prefix from persistent configuration.
  add-cdhash    Add an allowed cdhash to persistent configuration.
  remove-cdhash Remove an allowed cdhash from persistent configuration.

Example

1. Add a persistent allowed path:

   sudo amfidont add-path /Users/user/dev/myapp/build/Release/MyApp.app/
   

2. Start bypass mode (foreground):

   sudo amfidont --verbose
   

3. (Optional) Start as daemon instead:

   sudo amfidont daemon --verbose
   

4. (Optional) Spoof allowed binaries as Apple-signed:

   sudo amfidont --spoof-apple --verbose
   

   For example, this can be used to run self-signed arm64e binaries without setting the arm64e_preview_abi boot argument.

5. Stop foreground mode with Ctrl-C (this detaches amfidont and leaves amfid running).

Inner implementation details

• amfidont attaches to /usr/libexec/amfid using LLDB.
• It sets a breakpoint on:

-[AMFIPathValidator_macos validateWithError:]

• On each breakpoint hit, it inspects validator fields:
  • code path (codePath)
  • cdhash (cdhashAsData)
  • validation state (isValid)
• If the validator is invalid but the path/cdhash matches configured allow-rules, the return register is patched to success and execution continues.
• When --spoof-apple is enabled, an additional breakpoint is set on:

-[AMFIPathValidator_macos isApple]

This patches isApple to return true for allowed binaries, making them appear Apple-signed. For example, this allows running self-signed arm64e binaries without the arm64e_preview_abi boot argument.

• Persistent configuration is stored in:
  • ~/.amfidont/paths
  • ~/.amfidont/cdhashes