Ubuntu 14.04 LTS SSH login fails with permission denied

📖 ~1 min read

Table of contents

1. Symptom & Impact
2. Environment & Reproduction
3. Root Cause Analysis
4. Quick Triage
5. Step-by-Step Diagnosis
6. Solution – Primary Fix
7. Solution – Alternative Approaches
8. Verification & Acceptance Criteria
9. Rollback Plan
10. Prevention & Hardening
11. Related Errors & Cross-Refs
12. References & Further Reading

Symptom & Impact

Remote administration is blocked due to repeated auth failures.

Environment & Reproduction

Common after user home permission changes or key replacement.

Root Cause Analysis

Incorrect file modes, disabled auth methods, or wrong username mapping.

Quick Triage

Review /var/log/auth.log and confirm sshd service is healthy.

Step-by-Step Diagnosis

Validate key ownership, sshd_config directives, and account lock status.

Solution – Primary Fix

Correct permissions and auth settings, then reload sshd safely.

Solution – Alternative Approaches

Use console access to reset credentials and rebootstrap keys.

Verification & Acceptance Criteria

Key-based login succeeds and password policy behaves as expected.

Rollback Plan

Restore prior sshd_config backup and known-good authorized_keys file.

Prevention & Hardening

Use config management for sshd and monitor auth failure spikes.

Related Errors & Cross-Refs

Permission denied (publickey,password) and account restrictions.

Related tutorial: View the step-by-step tutorial for Ubuntu 14.04 LTS.

View all Ubuntu 14.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

OpenSSH server hardening and Ubuntu authentication docs.