O'Reilly logo

SSH, The Secure Shell: The Definitive Guide, 2nd Edition by Robert G. Byrnes, Richard E. Silverman, Daniel J. Barrett

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Tectia Plugins

The Tectia server can use external programs, known as plugins , for flexible handling of tasks like changing passwords [5.4.2.3], driving the process for keyboard-interactive authentication [5.4.5.2], or performing arbitrary checks for access control. [5.5.6] We’ll demonstrate how to use plugins with several examples:

  • Handling expired passwords

  • Extending keyboard-interactive authentication

  • Authorization

11.7.1 A Plugin for Changing Expired Passwords

Remember our discussion of expired passwords in Chapter 5? [5.4.2.3] We showed how Tectia’s SSH server can detect an expired password at authentication time, and prompt the user to change it:

    $ ssh server.example.com
    rebecca's password: < ... old, expired password ... >
    Authentication successful.
    < ... the following output is from running the passwd forced command ... >
    Changing password for user rebecca.

    Changing password for rebecca
    (current) UNIX password: < ... old, expired password, again ... >
    New password: < ... new password ... >
    Retype new password: < ... new password, again ... >
    passwd: all authentication tokens updated successfully.
    Connection to server.example.com closed.

The SSH server accomplishes this by calling either the system password-change program (e.g., passwd) or an alternative program specified by the PasswdPath configuration keyword. This technique, which is the default, uses a forced command to change the password. This method is conceptually simple but has several drawbacks:

  • No explicit indication ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required