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FileVault 2 Easily Decrypted

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Re: FileVault 2 Easily Decrypted

#13
post #2

tl;dr: direct memory access via firewire can recover the key within an hour. Anyone know if firewire be disabled at the hardware level on macs?

It's not really scanning memory, that's just their marketers trying to spin some razzlemadazzle for the plebes.

It's using Firewire Target Disk mode to get raw access to the disk. Apple stores its admin passwords using the highly obsolete MD5 algorithm, which is easily cracked in most cases using rainbow tables generated using the seed that is stored in plain text. It's pretty simply and I have personally broke into my own File Vault partitions after forgetting the password. You don't even need to spent $995, it's trivial to do with almost no skills. Anyone can do it themselves, which should convince them that File Vault is useless and its CPU load a pointless price to pay for zero security gain. This has all been dead obvious from day one too, the cited article is not even news, it's an advertisement for a company selling junk to clueless law enforcement incapable of doing basic research.

edit: OK, I'm wrong on some technical details:

1. Apple uses SHA-1 hashing not MD5.

2. I either need admin access in any account to access the /private/var/db/dslocal/nodes/Default/users/ folder and pull the plist with the hash from the account I am interested in, or I need to boot in Firewire mode which allows raw disk access to the unencrypted partition with that folder. (I haven't paid $995 for the referenced program but that would seem possible that's what it is really doing, not reading memory through FireWire looking for the plaintext password stored in the open in memory, which is also possible: http://www.hermann-uwe.de/blog/physical-memory-attacks-via-f... - this also helpfully notes that "sudo kextunload /System/Library/Extensions/IOFireWireFamily.kext/Contents/PlugIns/AppleFWOHCI.kext" deletes the relevant kernel extension to kill FW - I happen to already have this removed for other reasons.)

Still just as vulnerable to rainbow tables, but shoot maybe it does scan memory.

Re: FileVault 2 Easily Decrypted

#15
post #12

Since the MacBook Air doesn't have a FireWire port, can I assume this technique doesn't apply? Or would it still be possible using one of the other ports?

The thunderbolt port have DMA access also, so I suppose the technique applies as well.

Re: FileVault 2 Easily Decrypted

#16
post #4
post #3

Actually this applies to "all" other similar encryption technologies and is not limited to mac or firewire. You can also use Thunderbolt, PCMCIA, ExpressCard and even esata ports to have direct access to a computers RAM in which you passphrase is being held. Basically all ports which use DMA are possible if I remember correctly. Further reading: http://en.wikipedia.org/wiki/DMA_attack

Basically the only "defense" is to shut your computer down when you're leaving it alone / unattended for some time.

Actually, the "standard" solution is epoxy ("glue"). ;-)

Re: FileVault 2 Easily Decrypted

#17
post #4
post #3

Actually this applies to "all" other similar encryption technologies and is not limited to mac or firewire. You can also use Thunderbolt, PCMCIA, ExpressCard and even esata ports to have direct access to a computers RAM in which you passphrase is being held. Basically all ports which use DMA are possible if I remember correctly. Further reading: http://en.wikipedia.org/wiki/DMA_attack

Basically the only "defense" is to shut your computer down when you're leaving it alone / unattended for some time.

It should be mentioned that in the past the University of Princeton had successfully extracted encryption keys from a cold booted computer after the PC has been completely turned off.

They even demonstrate what they had recovered and how many bits has been lost.

Check this page and videos: https://citp.princeton.edu/research/memory/ https://citp.princeton.edu/research/memory/media/

Re: FileVault 2 Easily Decrypted

#19
post #4
post #3

Actually this applies to "all" other similar encryption technologies and is not limited to mac or firewire. You can also use Thunderbolt, PCMCIA, ExpressCard and even esata ports to have direct access to a computers RAM in which you passphrase is being held. Basically all ports which use DMA are possible if I remember correctly. Further reading: http://en.wikipedia.org/wiki/DMA_attack

Basically the only "defense" is to shut your computer down when you're leaving it alone / unattended for some time.

I use suspend-to-disk which suspends to my encryped swap partition. No need to "shut down" your computer, just don't use suspend-to-ram.

Re: FileVault 2 Easily Decrypted

#20
post #2

tl;dr: direct memory access via firewire can recover the key within an hour. Anyone know if firewire be disabled at the hardware level on macs?

It's not really scanning memory, that's just their marketers trying to spin some razzlemadazzle for the plebes. It's using Firewire Target Disk mode to get raw access to the disk. Apple stores its admin passwords using the highly obsolete MD5 algorithm, which is easily cracked in most cases using rainbow tables generated using the seed that is stored in plain text. It's pretty simply and I have personally broke into…

Wouldn't Firewire Target Disk mode just give them the encrypted data, i.e. useless? The admin passwords are stored on the encrypted partition.

edit: I guess your edits deprecate my reply

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