This key combination protected against malicious OROMs being inadvertently introduced into the macOS boot sequence. In macOS 10.12.3, the behavior of Mac computers sold after 2011 was changed to not execute OROMs by default at the time the Mac booted unless a special key combination was pressed.

Likewise, if the attacker introduces their own malicious device to the system, they’re also able to execute malicious code. However, because OROMs are generally rewritable, if an attacker overwrites the OROM of a legitimate peripheral, the attacker’s code executes early in the boot process and is able to tamper with the execution environment and violate the integrity of software that’s loaded later. This capability is required so that specialized third-party hardware can load and operate during the earliest startup phases-for example, to start up from external RAID arrays. The executed code is supposed to initialize and configure the hardware it was retrieved from, so that the hardware can be made usable by the rest of the firmware. (This is typically not a true ROM but is instead a rewritable chip that stores firmware.) On UEFI-based systems, that firmware is typically a UEFI driver, which is read in by the UEFI firmware and executed. Option ROM security in a Mac with the Apple T2 Security Chipīoth Thunderbolt and PCIe devices can have an “Option ROM (OROM)” physically attached to the device.

iPhone Text Message Forwarding security.

How iMessage sends and receives messages.

Adding transit and eMoney cards to Apple Wallet.

Rendering cards unusable with Apple Pay.

Adding credit or debit cards to Apple Pay.

How Apple Pay keeps users’ purchases protected.

Intro to app security for iOS and iPadOS.

Protecting access to user’s health data.

How Apple protects users’ personal data.

Activating data connections securely in iOS and iPadOS.

Protecting user data in the face of attack.

Protecting keys in alternate boot modes.

Encryption and Data Protection overview.

UEFI firmware security in an Intel-based Mac.

Additional macOS system security capabilities.

recoveryOS and diagnostics environments.

Contents of a LocalPolicy file for a Mac with Apple silicon.

LocalPolicy signing-key creation and management.

Boot process for iOS and iPadOS devices.Secure intent and connections to the Secure Enclave.Face ID, Touch ID, passcodes, and passwords.

Macintosh roms