Re: Physically securing FreeBSD workstations /boot/boot2
I seem to have found the answer to my own question. The question was: How do I prevent the boot2 bootstrap step from displaying a prompt where the user can load a custom boot program and/or force booting with options such as single user mode? The answer that seems to work for me: Add -n to /boot.config, I found this by ing the boot(8) man page. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: Physically securing FreeBSD workstations /boot/boot2
On 8/6/09, Nerius Landys nlan...@gmail.com wrote: Hi. I am attempting to secure some workstations in such a way that a user would not be able gain full control of the computer (only user access). However, they are able to see and touch the physical workstation. Things I'm trying to avoid, to list a couple of examples: 1. Go to BIOS settings and configure it to boot from CD first, then stick in a CD. To prevent this I've put BIOS to only boot from hard drive and I've password-locked the BIOS. You can't beat physical security. If you have access to the hardware, you can TAKE the box, saw it open, unmount the hard drive, slave it into another system, mount it as a data drive and steal the info. geli encryping the drive can secure the data on the disk, but they have your disk. it's as good as stolen data, even if they are unable to decrypt it. After sawing open the case, move the jumper to reset CMOS data, power up, change boot order, and boot off CD. After BIOS is back to normal, stick in a USB drive, boot off the HDD, which is self-decrypting the geli encryption, copy the data off, and scrub the HDD and install Windows on it. The hacker's OS (Just Kidding, all. Little humor is all I'm doing). 2. Go to loader menu and load (boot kernel) with some custom parameters or something. I've secured the loader menu by password-protecting it (/boot/loader.conf has password) and /boot/loader.conf is not world-readable. If you can do the above, even booting from alternate medium, no other means of security will apply. And I'm sure there are other things, I just forgot them. So my question is: Is this [securing of the workstation] worthwhile, or should I just forget about this kind of security? I want to make it so that the only way to gain full control of the computer is by physically opening up the box. I noticed that boot2 brings up a menu like this one when I press space during the initial boot blocks: FreeBSD/i386 BOOT Default: 0:ad(0,a)/boot/loader boot: I guess it would be possible to stick in a floppy disk or something and boot from there? So my question is, is this a threat to my plan, and if so, how can I disable this prompt? Only security in these days is to physically secure the box and leave it off the network. Flaws and security problems will always allow unauthorized access. But a computer that's not on the network is of no use. So it's a loose-loose situation. Best effort is to know your people, and either trust them, or fire them. --TJ ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: Physically securing FreeBSD workstations /boot/boot2
On Thu, Aug 06, 2009 at 01:35:55PM -0600, Tim Judd wrote: On 8/6/09, Nerius Landys nlan...@gmail.com wrote: Hi. I am attempting to secure some workstations in such a way that a user would not be able gain full control of the computer (only user access). However, they are able to see and touch the physical workstation. Things I'm trying to avoid, to list a couple of examples: 1. Go to BIOS settings and configure it to boot from CD first, then stick in a CD. To prevent this I've put BIOS to only boot from hard drive and I've password-locked the BIOS. You can't beat physical security. If you have access to the hardware, you can TAKE the box, saw it open, unmount the hard drive, slave it into another system, mount it as a data drive and steal the info. geli encryping the drive can secure the data on the disk, but they have your disk. it's as good as stolen data, even if they are unable to decrypt it. After sawing open the case, move the jumper to reset CMOS data, power up, change boot order, and boot off CD. After BIOS is back to normal, stick in a USB drive, boot off the HDD, which is self-decrypting the geli encryption, copy the data off, and scrub the HDD and install Windows on it. The hacker's OS (Just Kidding, all. Little humor is all I'm doing). You can (and should) set geli up to require a passphrase, instead of or next to a key-file. Using only a key-file is like sticking a tin-opener to the tin. 2. Go to loader menu and load (boot kernel) with some custom parameters or something. I've secured the loader menu by password-protecting it (/boot/loader.conf has password) and /boot/loader.conf is not world-readable. If you can do the above, even booting from alternate medium, no other means of security will apply. And I'm sure there are other things, I just forgot them. So my question is: Is this [securing of the workstation] worthwhile, or should I just forget about this kind of security? I want to make it so that the only way to gain full control of the computer is by physically opening up the box. I noticed that boot2 brings up a menu like this one when I press space during the initial boot blocks: FreeBSD/i386 BOOT Default: 0:ad(0,a)/boot/loader boot: I guess it would be possible to stick in a floppy disk or something and boot from there? So my question is, is this a threat to my plan, and if so, how can I disable this prompt? Disconnect or remove the floppy. Adn disable booting from USB devices. Roland -- R.F.Smith http://www.xs4all.nl/~rsmith/ [plain text _non-HTML_ PGP/GnuPG encrypted/signed email much appreciated] pgp: 1A2B 477F 9970 BA3C 2914 B7CE 1277 EFB0 C321 A725 (KeyID: C321A725) pgp0APKNpOUAz.pgp Description: PGP signature
Re: Physically securing FreeBSD workstations /boot/boot2
Nerius Landys wrote: Hi. I am attempting to secure some workstations in such a way that a user would not be able gain full control of the computer (only user access). However, they are able to see and touch the physical workstation. I assume that users cannot tingle with the hardware, take it apart, add a different disk etc. and that only authorized users can physically access the computer. That's what physical security is about. I understand you may have some authorized user who will nevertheless try to gain elevated privileges. That's really logical security, local that is as opposed to remote/network security. 2. Go to loader menu and load (boot kernel) with some custom parameters or something. I've secured the loader menu by password-protecting it (/boot/loader.conf has password) and /boot/loader.conf is not world-readable. And I'm sure there are other things, I just forgot them. You can configure the loader such as not to present any loader menu but boot right away. If you need the option of booting into single user mode, then you can password protect single user mode. So my question is: Is this [securing of the workstation] worthwhile, or should I just forget about this kind of security? I want to make it so that the only way to gain full control of the computer is by physically opening up the box. You can always make it more difficult, which should give you less to worry about. You have to weigh how much work it takes against how much you really have to worry about, then decide when it's enough. How about running diskless? How about centralized authentication with NIS or LDAP? Another option is to disable root locally, that is the account still exist but with * in the password field.. If each workstation runs sshd you can use key based authentication to gain privileged access remotely while local access is disabled. I noticed that boot2 brings up a menu like this one when I press space during the initial boot blocks: FreeBSD/i386 BOOT Default: 0:ad(0,a)/boot/loader boot: I guess it would be possible to stick in a floppy disk or something and boot from there? So my question is, is this a threat to my plan, and if so, how can I disable this prompt? you've still got floppies? wow. How about trying to boot a floppy with your current configuration? I'm not sure that it will work at that stage if it has been disabled in the bios. It might be possible to load the kernel from the harddisk then tell the kernel to mount the floppy as root device. You could solve that by compiling a kernel without floppy support and delete the kernel module. You need to learn how to script the loader, read the source code, I don't recall finding much documentation on that last time I looked. Others suggest you encrypt the harddrive, I don't find it very useful in your case, I assume your users need to access the systems and use them for the intended purposes and you just want to protect against someone trying to escalate his privileges. If you encrypt partitions with geli then you'll have to enter the password every time somebody reboots. However, you should consider encrypted swap and temporary partition, together with forced reboot on logout you avoid session data getting in the hands of the next user. BR, Erik -- Erik Nørgaard Ph: +34.666334818/+34.915211157 http://www.locolomo.org ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
