Ubuntu 22.04 LTS – SSH key login fails due to ~/.ssh permissions – Fix & Prevention

📖 ~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

Public key authentication is rejected and SSH access fails.

Environment & Reproduction

Often happens after file copy or backup restore.

Root Cause Analysis

OpenSSH denies keys when permissions or ownership are too permissive.

Quick Triage

Verify permission chain from home directory to authorized_keys.

Step-by-Step Diagnosis

Review effective sshd config and authentication decisions.

Solution – Primary Fix

Apply secure permissions and restart ssh service.

Solution – Alternative Approaches

Use temporary password auth under strict change control.

Verification & Acceptance Criteria

SSH public key authentication succeeds and logs confirm acceptance.

Rollback Plan

Restore previous sshd config if compatibility issues appear.

Prevention & Hardening

Audit SSH permission posture during provisioning.

Related Errors & Cross-Refs

Related to disabled PubkeyAuthentication and wrong AuthorizedKeysFile paths.

Related tutorial: View the step-by-step tutorial for Ubuntu 22.04 LTS.

View all Ubuntu 22.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Ubuntu OpenSSH hardening and key-management docs.