/etc/shadow – HowTo: Generate Password Hash in Linux

Linux stores users’ encrypted passwords, as well as other security information, such as account or password expiration values, in the /etc/shadow file.

Someday you may need to edit the /etc/shadow file manually to set or change ones password.

Unlike the /etc/passwd that is readable for everyone, the /etc/shadow file MUST be readable by the ROOT user only.

For this you would have to generate password hash in the format compatible with /etc/shadow.

Cool Tip: Want to create a USER with ROOT privileges? This can be very dangerous! But if you insist… Read more →

There is no need to install any additional tools as it can be easily done from the Linux command line using Python.

Generate Password Hash for /etc/shadow

The encrypted passwords in /etc/shadow file are stored in the following format:

$ID$SALT$ENCRYPTED

The $ID indicates the type of encryption, the $SALT is a random (up to 16 characters) string and $ENCRYPTED is a password’s hash.

Hash Type ID Hash Length
MD5 $1 22 characters
SHA-256 $5 43 characters
SHA-512 $6 86 characters

Cool Tip: Got a hash but don’t know what type is it? Find out how to easily identify different hash types! Read more →

Use the below commands from the Linux shell to generate hashed password for /etc/shadow with the random salt.

Generate MD5 password hash:

python -c "import random,string,crypt;
randomsalt = ''.join(random.sample(string.ascii_letters,8));
print crypt.crypt('MySecretPassword', '\$1\$%s\$' % randomsalt)"
---
$1$YjOzcqrf$Zqx4sx5CQRuEIFCdOLAJV0

Generate SHA-256 password hash:

python -c "import random,string,crypt;
randomsalt = ''.join(random.sample(string.ascii_letters,8));
print crypt.crypt('MySecretPassword', '\$5\$%s\$' % randomsalt)"
---
$5$LgsPuaeR$OCtm.3tpbS/wyOZAIy6dsVNP4x0GyohyGebkIz15e88

Generate SHA-512 password hash:

python -c "import random,string,crypt;
randomsalt = ''.join(random.sample(string.ascii_letters,8));
print crypt.crypt('MySecretPassword', '\$6\$%s\$' % randomsalt)"
---
$6$HMpFTkgb$WqzuqMqYbjWsXFrOtvZPo.1gIkH6HiXJGr4QPv.k26jE.3mE.sdf3dds[...]

Hope these commands will be helpful.

Just don’t forget to replace MySecretPassword with YourSecretPassword.

As you can see, it is really very easy to generate hashes for the /etc/shadow from the Linux command line using Python.

Particularly for the reason that the Python is installed by default on the most Linux distributions.