vault backup: 2025-01-30 17:33:17

Networking and Security/Week 20/hashcat-exercise/view-sample-password.sh

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+#!/bin/bash
+#
+# create (and destroy) a user account, in order to
+# capture and display its password as stored in /etc/shadow
+# and compare it the the password's pure hash
+#
+# david morgan 8/2014
+#
+
+clear
+if [ $(id -u) -ne 0 ];then echo "This script must be run as root"; exit 1; fi
+
+echo -n "Please supply a password: "; read password
+
+user=testuser$RANDOM
+useradd $user
+echo -en "$password\n$password\n" | passwd $user &> /dev/null
+record=$( tail -1 /etc/shadow )
+userdel $user
+
+passfield=$( echo $record | awk -F : '{print $2}' )
+
+hashtype=$( echo $passfield | awk -F $ '{print $2}' )
+salt=$( echo $passfield | awk -F $ '{print $3}' )
+storedpass=$( echo $passfield | awk -F $ '{print $4}' )
+
+
+echo -en "\nThis is the password record generated in /etc/shadow for a new user with your chosen password: \n\t$record"
+echo -en "\nand this is its password related field: \n\t"; echo $record | awk -F : '{print $2}'
+echo -en "\n...and these are that password field's components:\n" 
+echo -en "hash-type code                $hashtype"
+case $hashtype in
+	1 )
+		echo ' (md5)'
+		;;
+	5 )
+		echo ' (sha-256)'
+		;;
+	6)
+		echo ' (sha-512)'
+		;;
+esac
+echo -e "salt                          $salt"
+echo -e "stored/scrambled password     $storedpass"
+echo
+
+
+
+saltedpassword=$( echo ${salt}${password} )
+echo -e "Salted password (password prefixed with salt):\n\t$saltedpassword"
+case $hashtype in
+	6 )
+	echo -en "pure sha512 hash of this salted password:\n\t"
+	purehash=$(echo -n $saltedpassword | sha512sum | cut -d " " -f 1)
+	;;
+	5 )
+	echo -en "pure sha256 hash of this salted password:\n\t"
+	purehash=$(echo -n $saltedpassword | sha256sum | cut -d " " -f 1)
+	;;
+	1 )
+	echo -en "pure md5 hash of this salted password:\n\t"
+	purehash=$(echo -n $saltedpassword | md5sum | cut -d " " -f 1) 
+	;;
+esac
+echo $purehash
+
+cat<<EOF
+
+Note that password processing with a given hash algorithm does something
+OTHER than merely hash with that algorithm, as shown by the fact that 
+the stored/processed password ($storedpass)
+and the pure hash ($purehash)
+are NOT the same.
+
+( see  man 3 crypt  and  man mkpasswd )
+
+EOF