91 lines
2.6 KiB
Markdown
91 lines
2.6 KiB
Markdown
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# CIS-Inspired Debian and Ubuntu Hardening
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This role applies a small, practical set of CIS-inspired operational hardening controls for Debian and Ubuntu servers. It is intentionally readable, conservative, and suitable as a baseline for production environments that still need local review.
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## Supported OS
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- Debian 13 Trixie
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- Ubuntu Server 26.04 LTS
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Unsupported distributions and versions fail during precheck before hardening tasks run.
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## Implemented Areas
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- SSH daemon hardening with a validated drop-in configuration
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- Legacy network package removal
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- Optional installation and enablement of `auditd`, `chrony`, `rsyslog`, and `sudo`
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- Kernel network sysctl hardening
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- Basic audit rule examples, disabled by default
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- Sudo `use_pty` and optional sudo logfile configuration
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- Logging service checks without replacing existing logging configuration
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- Filesystem mount option recommendations, disabled by default
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## Safety Philosophy
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The defaults are intended to be operationally safe:
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- Check mode is supported.
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- SSH password authentication remains enabled by default.
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- Filesystem mount option management is disabled by default.
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- Audit rules are not written unless explicitly enabled.
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- Services are enabled only when the matching feature is enabled and the service exists.
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- Existing logging configuration is not replaced.
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This role does not implement the full CIS benchmark and is not a CIS certification implementation.
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## Usage
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Run in check mode first:
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```bash
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ansible-playbook playbooks/cis-debian-ubuntu-hardening.yml --check --diff
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```
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Apply the full baseline:
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```bash
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ansible-playbook playbooks/cis-debian-ubuntu-hardening.yml
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```
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Run only selected areas:
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```bash
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ansible-playbook playbooks/cis-debian-ubuntu-hardening.yml --tags precheck,ssh,postcheck
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ansible-playbook playbooks/cis-debian-ubuntu-hardening.yml --tags packages,services
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ansible-playbook playbooks/cis-debian-ubuntu-hardening.yml --tags sudo,logging
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```
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## Key Variables
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```yaml
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cis_disable_root_login: true
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cis_disable_password_auth: false
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cis_install_auditd: true
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cis_enable_chrony: true
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cis_enable_rsyslog: true
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cis_remove_legacy_packages: true
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cis_enable_sysctl_hardening: true
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cis_manage_mount_options: false
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cis_manage_audit_rules: false
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cis_ssh_max_auth_tries: 4
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cis_ssh_login_grace_time: 60
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cis_ssh_client_alive_interval: 300
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cis_ssh_client_alive_count_max: 3
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cis_sudo_use_pty: true
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cis_sudo_logfile: /var/log/sudo.log
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```
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Enable audit rules only after reviewing the examples:
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```yaml
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cis_manage_audit_rules: true
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```
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Enable mount option persistence only after reviewing each filesystem target:
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```yaml
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cis_manage_mount_options: true
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```
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