Automating Password Rotation Policies with Shell Scripting

The password expired at midnight. By 12:01, no one could log in.

This is the reality of strict password rotation policies. They protect systems but can cripple teams if not managed with care. Manual rotation works until scale kills it. Audit requirements, compliance rules, and security frameworks demand automation. Shell scripting is the simplest weapon you have.

Why password rotation policies matter

Password rotation policies enforce that credentials change on schedule, often every 30, 60, or 90 days. They reduce risk from leaked or compromised passwords. They are part of CIS benchmarks, ISO 27001 controls, and SOC 2 readiness. Without automation, they become brittle and error-prone.

Shell scripting for password rotation

A shell script can manage the entire rotation process:

• Identify accounts due for rotation
• Generate complex, compliant passwords
• Update credentials securely in systems or config files
• Notify stakeholders automatically

Example in Bash:

#!/bin/bash
USER_LIST="/etc/rotation/users.txt"

for USER in $(cat $USER_LIST); do
 NEW_PASS=$(openssl rand -base64 16)
 echo "$USER:$NEW_PASS"| chpasswd
 echo "Password rotated for $USER"
done

This script reads a list of users, creates a random password, and applies it. Replace chpasswd with API calls or secrets manager updates if needed. Integrate logging to maintain audit trails.

Best practices in password rotation with shell scripts

1. Use strong password generators – Prefer openssl rand or pwgen over basic random functions.
2. Avoid plain text storage – Store new credentials only in encrypted vaults.
3. Maintain audit logs – Record change timestamps, responsible operator, and rotation method.
4. Test before deployment – Run in staging to avoid account lockouts.
5. Integrate with CI/CD pipelines – Tie rotations to build or deployment milestones.

Common pitfalls

• Hardcoding credentials in scripts
• No rollback plan if rotation breaks services
• Ignoring service accounts in automation
• Forgetting API keys and tokens which also need rotation

Automating password rotation policies with shell scripting turns a compliance burden into a low-maintenance routine. It gives you speed, accuracy, and control over your security posture.

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