AMFID code signing evasion

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By creating a dylib without code, just redefining the signed code verification function with a "return ok" method from another signed library and using lazy binding, the entire code signing requirement gets circumvented. This method has been used by developers for a long time now.

In evasi0n, the amfi.dylib redefines these functions:

  • _kMISValidationOptionValidateSignatureOnly (_kCFUserNotificationTokenKey from CoreFoundation)
  • _kMISValidationOptionExpectedHash (_kCFUserNotificationTimeoutKey from CoreFoundation)
  • _MISValidateSignature (_CFEqual from CoreFoundation)

TODO: some more detailed description missing here.

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