Linux System Recovery

Restoring secure SSH access, repairing user permissions, and enforcing least‑privilege principles during a controlled system recovery.

01. OVERVIEW

This project covers recovering a Linux system after access failure caused by broken SSH key configurations and misaligned user permissions. The focus was on restoring secure authentication, enforcing least‑privilege access, and ensuring operational safety throughout the recovery workflow.

02. METHODOLOGY

  • SSH Key Repair: Identified mismatched or corrupted key pairs, regenerated secure keys, and restored proper permissions for ~/.ssh directories.
  • Access Restoration: Updated authorized_keys, validated sshd_config, and tested authentication using non‑privileged accounts.
  • User & Permission Fixes: Audited user groups, corrected ownership issues, and enforced least‑privilege access across system directories.
  • Operational Safety: Performed recovery through TTY/local console, backed up configs before modification, and validated system integrity post‑recovery.

TECH STACK

Linux (Ubuntu/Debian) SSH / OpenSSH Systemd File Permissions ACLs Sudoers journalctl auth.log TTY Recovery

A locked-out server means lost access and, potentially, lost data. A controlled recovery process restores access without introducing new risk or compounding the original problem.