Bug 7740 - sha512crypt is no longer a good password hash/PBKDF
Summary: sha512crypt is no longer a good password hash/PBKDF
Status: NEW
Alias: None
Product: ThinLinc
Classification: Unclassified
Component: Web Administration (show other bugs)
Version: trunk
Hardware: PC Unknown
: P2 Normal
Target Milestone: LowPrio
Assignee: Bugzilla mail exporter
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2021-07-05 16:40 CEST by Pierre Ossman
Modified: 2023-08-29 07:29 CEST (History)
0 users

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Description Pierre Ossman cendio 2021-07-05 16:40:13 CEST
We currently use the sha512crypt algorithm for storing the password for tlwebadm. This algorithm is very popular on Linux systems and is still the default algorithm for /etc/shadow.

However it is starting to show its age and it is not very good at protecting against GPU and ASIC attacks. The crypt(5) man page calls it "acceptable" for new hashes rather than "recommended".

(It also states that the default cost of 5000 is too low for modern machines, which is another issue.)

The state-of-the-art seems to be the Argon2 algorithm, but it has yet to be formalised with a crypt() format. However the scrypt algorithm, and some derivatives, are more properly included.



A somewhat inflammatory blog post about current algorithms:

https://pthree.org/2018/05/23/do-not-use-sha256crypt-sha512crypt-theyre-dangerous/
Comment 1 Pierre Ossman cendio 2021-12-17 14:53:27 CET
(In reply to Pierre Ossman from comment #0)
> (It also states that the default cost of 5000 is too low for modern
> machines, which is another issue.)
> 

As a counter point, DISA thinks that 5000 is the lower limit, but good enough, in their STIG for RHEL 8.

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