Re: Crack Mysql Password Hash Calculator
Nelson Suggs
So, modifying @Gilles's answer just a bit, how about a little shell script that uses Python, like the following. You could easily modify this to run a SQL statement against your MySQL database to set the password all at once. But even without going that far, just copy and paste the resulting hash into a SQL statement to update the users table:
This MD5 hash generator is useful for encoding passwords, credit cards numbers and other sensitive date into MySQL, Postgress or other databases. PHP programmers, ASP programmers and anyone developing on MySQL, SQL, Postgress or similar should find this online tool an especially handy resource.
An MD5 hash is created by taking a string of an any length and encoding it into a 128-bit fingerprint. Encoding the same string using the MD5 algorithm will always result in the same 128-bit hash output. MD5 hashes are commonly used with smaller strings when storing passwords, credit card numbers or other sensitive data in databases such as the popular MySQL. This tool provides a quick and easy way to encode an MD5 hash from a simple string of up to 256 characters in length.
MD5 is often used as a checksum algorithm. Text or files are fed into the MD5 algorithm and the resulting hash would change if the file had been changed. This is done to detect malicious tampering, or file corruption.MD5 has also historically been used as a password hashing algorithm. Password hashing algorithms allow a password to be stored, in a website's database for instance, without having to store the actual password. This makes it more difficult to steal passwords, and if the hash is taken, the user's password is not necessarily compromised. When using a hashing algorithm for passwords it is wise to use "salt". With MD5, salt is added by concatinating a string unrelated to the password to the user supplied password string. MD5 has since been deemed too weak for this, and was succeeded by SHA-1 and then SHA-2.
A plain MD5 hash: I love Dan's Tools! results in a hash of acf014f1bc68c2af42e1e349221e403b.An MD5 Hash with salt for a user supplied password of supersecret would be salted so the input for the MD5 is saltstringsupersecret. This would result in a hash of 75f94b73c4b8564b6e07369b031764b6.code white-space: normal;LanguageEncodeNotesPHPmd5($string);Perlmd5($string);*requires use Digest::MD5 qw(md5 md5_hex md5_base64);
The information in this section applies fully only before MySQL 5.7.5, and only for accounts that use the mysql_native_password or mysql_old_password authentication plugins. Support for pre-4.1 password hashes was removed in MySQL 5.7.5. This includes removal of the mysql_old_password authentication plugin and the OLD_PASSWORD() function. Also, secure_auth cannot be disabled, and old_passwords cannot be set to 1.
MySQL lists user accounts in the user table of the mysql database. Each MySQL account can be assigned a password, although the user table does not store the cleartext version of the password, but a hash value computed from it.
When a client attempts to connect to the server, there is an initial authentication step in which the client must present a password that has a hash value matching the hash value stored in the user table for the account the client wants to use.
After the client connects, it can (if it has sufficient privileges) set or change the password hash for accounts listed in the user table. The client can do this by using the PASSWORD() function to generate a password hash, or by using a password-generating statement (CREATE USER, GRANT, or SET PASSWORD).
In other words, the server checks hash values during authentication when a client first attempts to connect. The server generates hash values if a connected client invokes the PASSWORD() function or uses a password-generating statement to set or change a password.
Password hashing methods in MySQL have the history described following. These changes are illustrated by changes in the result from the PASSWORD() function that computes password hash values and in the structure of the user table where passwords are stored.
For compatibility purposes, the old_passwords system variable was added, to enable DBAs and applications control over the hashing method. The default old_passwords value of 0 causes hashing to use the 4.1 method (41-byte hash values), but setting old_passwords=1 causes hashing to use the pre-4.1 method. In this case, PASSWORD() produces 16-byte values and is equivalent to OLD_PASSWORD()
In addition, the mysql client supports a --secure-auth option that is analogous to secure_auth, but from the client side. It can be used to prevent connections to less secure accounts that use pre-4.1 password hashing. This option is disabled by default before MySQL 5.6.7, enabled thereafter.
Upgrades from MySQL 4.1 or later to current versions of MySQL should not give rise to any issues in regard to the Password column because both versions use the same column length and password hashing method.
The 4.1 hashing method is understood only by MySQL 4.1 (and higher) servers and clients, which can result in some compatibility problems. A 4.1 or higher client can connect to a pre-4.1 server, because the client understands both the pre-4.1 and 4.1 password hashing methods. However, a pre-4.1 client that attempts to connect to a 4.1 or higher server may run into difficulties. For example, a 4.0 mysql client may fail with the following error message:
The differences between short and long password hashes are relevant both for how the server uses passwords during authentication and for how it generates password hashes for connected clients that perform password-changing operations.
The way in which the server generates password hashes for connected clients is affected by the width of the Password column and by the old_passwords system variable. A 4.1 or later server generates long hashes only if certain conditions are met: The Password column must be wide enough to hold long values and old_passwords must not be set to 1.
The Password column must be wide enough to hold long hashes (41 bytes). If the column has not been updated and still has the pre-4.1 width of 16 bytes, the server notices that long hashes cannot fit into it and generates only short hashes when a client performs password-changing operations using the PASSWORD() function or a password-generating statement. This is the behavior that occurs if you have upgraded from a version of MySQL older than 4.1 to 4.1 or later but have not yet run the mysql_upgrade program to widen the Password column.
If the Password column is wide, it can store either short or long password hashes. In this case, the PASSWORD() function and password-generating statements generate long hashes unless the server was started with the old_passwords system variable set to 1 to force the server to generate short password hashes instead.
The purpose of the old_passwords system variable is to permit backward compatibility with pre-4.1 clients under circumstances where the server would otherwise generate long password hashes. The option does not affect authentication (4.1 and later clients can still use accounts that have long password hashes), but it does prevent creation of a long password hash in the user table as the result of a password-changing operation. Were that permitted to occur, the account could no longer be used by pre-4.1 clients. With old_passwords disabled, the following undesirable scenario is possible:
The next time the old client attempts to connect to the account, it cannot, because the account has a long password hash that requires the 4.1 hashing method during authentication. (Once an account has a long password hash in the user table, only 4.1 and later clients can authenticate for it because pre-4.1 clients do not understand long hashes.)
This scenario illustrates that, if you must support older pre-4.1 clients, it is problematic to run a 4.1 or higher server without old_passwords set to 1. By running the server with old_passwords=1, password-changing operations do not generate long password hashes and thus do not cause accounts to become inaccessible to older clients. (Those clients cannot inadvertently lock themselves out by changing their password and ending up with a long password hash.)
The downside of old_passwords=1 is that any passwords created or changed use short hashes, even for 4.1 or later clients. Thus, you lose the additional security provided by long password hashes. To create an account that has a long hash (for example, for use by 4.1 clients) or to change an existing account to use a long password hash, an administrator can set the session value of old_passwords set to 0 while leaving the global value set to 1:
For connected clients, password hash-generating operations involving the PASSWORD() function or password-generating statements use short hashes exclusively. Any change to an account's password results in that account having a short password hash.
This scenario occurs when a pre-4.1 MySQL installation has been upgraded to 4.1 or later but mysql_upgrade has not been run to upgrade the system tables in the mysql database. (This is not a recommended configuration because it does not permit use of more secure 4.1 password hashing.)
In this scenario, newly created accounts have short password hashes because old_passwords=1 prevents generation of long hashes. Also, if you create an account with a long hash before setting old_passwords to 1, changing the account's password while old_passwords=1 results in the account being given a short password, causing it to lose the security benefits of a longer hash.
To create a new account that has a long password hash, or to change the password of any existing account to use a long hash, first set the session value of old_passwords set to 0 while leaving the global value set to 1, as described previously.
aa06259810