Defeating a Laptop's BIOS Password
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Defeating a Laptop's BIOS Password
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Re: Defeating a Laptop's BIOS Password
#2> Even today's modern 64-bit CPUs begin execution in 16-bit mode. In UEFI, this is called the SEC phase.
Is that true even for the T2 Macs and such?
Re: Defeating a Laptop's BIOS Password
#3> Even today's modern 64-bit CPUs begin execution in 16-bit mode. In UEFI, this is called the SEC phase. Is that true even for the T2 Macs and such?
I'm not that familiar with Macs, but if they're using an Intel CPU it almost definitely starts in 16-bit mode. From what I understand the T2 chip is more akin to what's called an embedded controller in other laptops.
Re: Defeating a Laptop's BIOS Password
#4Question: how secure are BIOS passwords, really? If you have full-disk encryption anyway, is the BIOS password adding anything?
Re: Defeating a Laptop's BIOS Password
#5> Even today's modern 64-bit CPUs begin execution in 16-bit mode. In UEFI, this is called the SEC phase. Is that true even for the T2 Macs and such?
I'm not that familiar with Macs, but if they're using an Intel CPU it almost definitely starts in 16-bit mode. From what I understand the T2 chip is more akin to what's called an embedded controller in other laptops.
According to the CPU processor manuals, they all boot in "real mode" which is a 16-bit legacy/bootstrap mode.
Re: Defeating a Laptop's BIOS Password
#6Question: how secure are BIOS passwords, really? If you have full-disk encryption anyway, is the BIOS password adding anything?
well, you could make the machine boot on another device and potentially trick someone into entering their credentials on a "phishing" screen.
Re: Defeating a Laptop's BIOS Password
#7Question: how secure are BIOS passwords, really? If you have full-disk encryption anyway, is the BIOS password adding anything?
The BIOS does control the boot order sequence for instance.
I guess if you have access to it, you could force boot from a malicious USB stick, or the network, that would simulate the disk decryption prompt.
I guess you could also remove security measures that your company put in place to e.g. prevent the usage of USB to prevention information leak.
Re: Defeating a Laptop's BIOS Password
#8Question: how secure are BIOS passwords, really? If you have full-disk encryption anyway, is the BIOS password adding anything?
If you have physical access and a flash programmer they're not secure at all. If you're trying to stop a random passerby from messing with your firmware settings they're great.
Re: Defeating a Laptop's BIOS Password
#9> Even today's modern 64-bit CPUs begin execution in 16-bit mode. In UEFI, this is called the SEC phase. Is that true even for the T2 Macs and such?
There's coverage of that in Apple's Platform Security documentation.
https://support.apple.com/guide/security/uefi-firmware-overv...
Re: Defeating a Laptop's BIOS Password
#10> Even today's modern 64-bit CPUs begin execution in 16-bit mode. In UEFI, this is called the SEC phase. Is that true even for the T2 Macs and such?
The T2's job is to bring the main processor out of reset. The actual booting is standard UEFI, apparently.