Software⏱️ 4 min read📅 2026-06-11

How to Fix: Trying to change a Ubuntu user's password, authentication token manipulation error

Error changing password for local user in Ubuntu shadow file.

Quick Answer: Try using the "-S" option with passwd to specify a password, e.g. sudo passwd -S jamz

📋 Table of Contents

  1. 🛑 Root Causes of the Error
  2. ✅ Best Solutions to Fix It
  3. ✨ Wrapping Up

The 'Authentication token manipulation error' is a common issue that affects users trying to change or create passwords on Ubuntu systems. This error occurs when the system is unable to properly validate the authentication tokens used for password changes, resulting in an inability to set a new password.

This frustration can be particularly vexing for system administrators and users alike, as it prevents them from securing their accounts effectively. In this troubleshooting guide, we will walk through the steps to resolve this issue and regain control over password management.

🛑 Root Causes of the Error

  • The primary reason for this error is a mismatch between the authentication token format used by the system and the one provided during the password change process. This can occur due to various factors such as outdated or corrupted system libraries, incorrect configuration of the PAM (Pluggable Authentication Module) stack, or issues with the user's environment.
  • An alternative reason for this error could be related to the user's environment settings, particularly if they are using a non-standard shell or have modified their environment variables. In such cases, the system may not be able to properly validate the authentication tokens used for password changes.

✅ Best Solutions to Fix It

Resetting the PAM Stack

  1. Step 1: Step 1: Stop and disable any running services that might interfere with the PAM stack. This can include services like SSH, NFS, or other network protocols.
  2. Step 2: Step 2: Locate the PAM configuration file for user authentication (usually located at /etc/pam.d/common-auth) and modify it to use the standard authentication token format. You may need to edit this file with a text editor as root using the command `sudo nano /etc/pam.d/common-auth`.
  3. Step 3: Step 3: Restart the PAM stack by running the command `sudo service pam systemctl restart` (on Ubuntu systems) or `sudo service pam auth restart` (on older systems).

Resetting User Environment Variables

  1. Step 1: Step 1: Log out of the user account and log back in to reset their environment variables. This can be done by running the command `sudo userdel -r jamz` (to remove the user) or simply logging out and back in as the user.
  2. Step 2: Step 2: Verify that the user's shell configuration files are not interfering with the PAM stack. You may need to reset the user's environment variables using a script like `~/.profile` or `~/.bashrc`. However, be cautious when modifying these files, as incorrect changes can lead to further issues.

✨ Wrapping Up

By following these steps and addressing the root causes of the 'Authentication token manipulation error', you should be able to successfully change the password for the user account. Remember to always verify your work and test the resolution before proceeding with any critical system updates or modifications.

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