Do NOT use SHA-1: LUKS disk encryption

What the..?

As the cryptography expert Bruce Schneier already told in year 2005, do not use SHA-1 because its broken. See his article here: http://www.schneier.com/blog/archives/2005/02/sha1_broken.html

Several years ago, many governments also recommended to stop using this one.

Does linux LUKS use SHA-1?

Yes it does by default. 

Just create a Volume/Container with default values (e.g. cryptsetup luksFormat /dev/loop0).

Did you use the debian installer to encrypt your LUKS device? Same thing.

How do i verify if i use SHA-1 on LUKS?

Thats simple. 

Just fire up "cryptsetup luksDump" on your encrypted volume. (e.g. cryptsetup luksDump /dev/loop0)

Which Hash should i alternatively use?

At time of writing (year 2013) and in this context, we recommend SHA512. 

Can i change the current hash in LUKS on-the-fly?

No you can NOT. You need to re-encrypt your device. There is a experimental tool from the authors of cryptsetup, called "cryptsetup-reencrypt" which is included in the official source-code. We succeeded in reencrypting a system-volume encrypted with aes and sha-1 hash, and switched to twofish as encryption algorithm and sha512 as hash  by the command: 

./cryptsetup-reencrypt -c  twofish-xts-plain -h sha512 /dev/loop0

Please be very careful and use a backup before using this tool!

So, i am insecure when not switching?

It depends. For the most people the default settings are secure. In LUKS we also have PBKDF2 in front of, which prevents/reduces many forms of attacks. 

The main reason is: why should i use something insecure like SHA-1? Just for comfort? 

Attacking the Windows 7/8 Address ASLR

The following text is what looks like an attempt to circumvent windows 7 and windows 8 memory protections in order to execute arbritrary assembly code. The presented methods are in particular useful for client-side attacks as used for example in browser exploits.

The topic that is discussed is a very complex one. At the time I started the research I thought the idea behind the attack will be applied to real-world scenarios quick and easy. I had to be convinced by the opposite.
The research was done without knowing much about the real internals of the windows memory space protection but rather using brute force, trial & failure in order to achieve what will be presented in the upcoming text. Be warned - the methods to attack the protection mechanisms hereby presented are not
failsafe and can be improved. Tough in many cases it is possible tocompletely bypass Windows 7 and especially Windows 8 ASLR by using thetechniques.


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