While fighting with DB2 denying logins I had to change the default hash algorithm used to store passwords in /etc/shadow.
As far as I know (and as grep -i -r "sha512" /etc/* tells me
), there are two files that carry this information.
Namely /etc/pam.d/common-password and
/etc/login.defs.
To change the algorithm from sha512 (which shifts as the default in the new Ubuntu releases) change this:
/etc/pam.d/common-password
password [success=1 default=ignore] pam_unix.so obscure sha512
to
password [success=1 default=ignore] pam_unix.so obscure md5
/etc/login.defs
ENCRYPT_METHOD SHA512
to
ENCRYPT_METHOD MD5
Hi there
Thanks for this entry, it is well explained and understandable.
Yet I still got a question (which hasn't really something to do with the algorithm, but anyway you may have an idea)..
I'm wondering whether it's possible to reset the passphrase – I may have changed it or just forgot it, and now I wonder if I could maybe encrypt a string (new password) with the right algorithm and then replace the hash of the old password in a specific file (I still can start up my system n all that..)
Greets
Hi ainande,
use
echo username:password | chpasswd -S -c MD5
If supports both MD5 and SHA512 (besides others). Salt is generated randomly.
To generate MD5 password only (without having to give the username) you can use
openssl passwd –1 -salt xyz
In this case, you choose the salt.