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Re: password hash in shadow file



On 13/03/18 09:47 AM, tomas@tuxteam.de wrote:

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Tue, Mar 13, 2018 at 05:25:18PM +0100, Sven Hartge wrote:
Adam Weremczuk <adamw@matrixscience.com> wrote:

I think it was me invoking "passwd" as root and aborting (ctrl+D)
without making any changes.  Would that be enough to update the shadow
file?

No.

You can't reverse a hash and to generate a new hash the code needs the
password for the user in plain.

Well, to be fair, the change to SHA-1 is because you can "reverse"
MD5 all too easily (where reverse just means that you find something
which hashes to a given hash, which hasn't to resemble your original
password all too much). Usually you want this something to have
some properties to be useful.

But I don't think your operating system is going to do that behind
your back ;-)

Not if it's Linux, anyway...

--
cgibbs@surfnaked.ca (Charlie Gibbs)


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