Reset Weblogic Password

In order to reset the weblogic admin password incase of lost/forgotten

1. Shut down the WebLogic domain, the managed servers, Admin Server and Node Manager.
2. Set the following environment variables in the command prompt (cmd) to help you navigate easily, in my case for Windows O/S:
• set MW_HOME=\Oracle\Middleware\Oracle_Home
• set DOMAIN_HOME=%MW_HOME%\user_projects\domains\base_domain
  NB: If you are on Linux O/S, use export instead of set and $MW_HOME instead of %MW_HOME%
3.  Rename the data folder under the AdminServer of the domain to old_data, this is the path: %DOMAIN_HOME%\servers\AdminServer\data
4.  In the same command prompt that you opened earlier, set the environment variable of the domain by calling: %DOMAIN_HOME%\bin\setDomainEnv.cmd or ./setDomainEnv.sh in Linux.
5. In the same command prompt, change directory to security folder: cd %DOMAIN_HOME%\security
6. Inside the %DOMAIN_HOME%\security directory, move the file "DefaultAuthenticatorInit.ldift" to "%DOMAIN_HOME%\security\old\" In the next step, the command that we are going to run will create a new file “DefaultAuthenticatorInit.ldift” in the security folder
7. Run the following command to reset or change admin password:
     java weblogic.security.utils.AdminAccount  weblogic welcome123 .
• NB: "weblogic" is user name and "welcome123" is the new password which we need to set.
• NB: The DOT at the end of the above command represents the current directory. A new "DefaultAuthenticatorInit.ldift" file will be created in the current directory when you execute the command.
8. Update the "boot.properties" file under the directory %DOMAIN_HOME%\servers\AdminServer\security\ with your username and the new password.
9. Now start the admin server using the new credentials from %DOMAIN_HOME%\bin\startWeblogic.cmd in Windows or ./startWeblogic.sh in Linux.
10. Once the AdminServer started, login into the Admin console using the username and the new password

Check the WebLogic Documentation for further guidance

Reference : https://blogs.oracle.com/imc/entry/change_password_in_weblogic