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You’re in the front of a Linux computer, you need a root access. What do you do?

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Re: You’re in the front of a Linux computer, you need a root access. What do you do?

#31

Post by quasque »

afhsfsfdsss88 wrote: post #27
Piskvorrr wrote: post #2

Grub is password-protected, what do you do? (Boot from a live distro and chroot into the on-disk one)

This is what came to me first. I have unrestricted physical access? I probably own the machine. If the data on the storage is not encrypted, I own that too. If I don't want to disassemble anything, I just plug in a liveUSB and it's all mine. If the BIOS has USB/CD boot disabled? I pull the CMOS battery. If that fails? The google probably knows the BIOS reset sequence for your board and soon so will I. ===============…

The CMOS battery often has nothing to do with BIOS settings, on many modern laptops it's stored in the BIOS flash memory, with no such reset sequence available.

If properly secured, physical hacking is not as easy as it used to be.

Re: You’re in the front of a Linux computer, you need a root access. What do you do?

#32

Post by afhsfsfdsss88 »

quasque wrote: post #31
afhsfsfdsss88 wrote: post #27

Earlier quoted context omitted.

This is what came to me first. I have unrestricted physical access? I probably own the machine. If the data on the storage is not encrypted, I own that too. If I don't want to disassemble anything, I just plug in a liveUSB and it's all mine. If the BIOS has USB/CD boot disabled? I pull the CMOS battery. If that fails? The google probably knows the BIOS reset sequence for your board and soon so will I. ===============…

The CMOS battery often has nothing to do with BIOS settings, on many modern laptops it's stored in the BIOS flash memory, with no such reset sequence available. If properly secured, physical hacking is not as easy as it used to be.

NVRAM can be overwritten with a factory fresh BIOS image....

Re: You’re in the front of a Linux computer, you need a root access. What do you do?

#33

Post by quasque »

afhsfsfdsss88 wrote: post #32
quasque wrote: post #31

Earlier quoted context omitted.

The CMOS battery often has nothing to do with BIOS settings, on many modern laptops it's stored in the BIOS flash memory, with no such reset sequence available. If properly secured, physical hacking is not as easy as it used to be.

NVRAM can be overwritten with a factory fresh BIOS image....

Yes, but then you're in the realm of interfacing directly with the hardware to reflash the chip, somewhat upping the difficulty of this hack.

Re: You’re in the front of a Linux computer, you need a root access. What do you do?

#34

Post by walesmd »

Edit the kernel entry in grub to boot into single user mode (by appending a 1 to the line), boot, you're now free to change root's password.

This is what we did to a number of machines at this year's SouthWest CCDC we were provided no login information for.

Re: You’re in the front of a Linux computer, you need a root access. What do you do?

#35

Post by lutusp »

ominous_prime wrote: post #7
marcosdumay wrote: post #5

One does not even need to enable password protection of Grub. Linux will ask for the root password before granting access to recovery mode. That stopped working at the early 2000s. The author must use a pretty stupid distro to not notice it by 2013. Anyway, want to gain access to the computer? Get a screwdriver.

Ubuntu does not require a root password, because there isn't one. The default setup is to always require sudo to access root.

> Ubuntu does not require a root password, because there isn't one.

That's true, but creating a root password in Ubuntu is child's play:

$ sudo passwd

(enter user password for sudo access to root privilege level)

(enter new password for root)

(re-enter new password for root)

Done.

> The default setup is to always require sudo to access root.

Yes, but this is a cosmetic distinction, not a basic one. Setting up a root password is always a few keystrokes away.

My point? Ubuntu isn't really different from other distros in this respect, it only appears to be.

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