mitigations.md

Mitigation Strategies Analysis for borgbackup/borg

Mitigation Strategy: Strong Key Generation with borg key generate

• Description:
  1. Developers should utilize the borg key generate command, a built-in Borg utility, to create robust encryption keys when initializing new Borg repositories.
  2. During key generation, emphasize the critical importance of setting a strong and unique passphrase. This passphrase directly encrypts the Borg repository key, protecting it from unauthorized access.
  3. Educate users and administrators on best practices for passphrase creation specifically for Borg keys: recommend sufficient length, complexity (incorporating a mix of character types), and avoidance of easily guessable phrases or reused passwords.
  4. Provide clear and accessible documentation detailing the borg key generate process within the application's security guidelines and backup setup procedures. This ensures consistent and secure key generation practices for all Borg repository deployments.
• List of Threats Mitigated:
  • Unauthorized Repository Access (High Severity) - Weakly generated Borg keys are susceptible to brute-force attacks, potentially granting attackers unauthorized access to the entire backup repository.
  • Data Breach (High Severity) - If a Borg key is compromised due to weak passphrase encryption, attackers can decrypt and exfiltrate all sensitive data contained within the Borg backups.
• Impact: Significantly reduces the risk of unauthorized repository access and data breaches by making brute-force attacks against the passphrase protecting the Borg key computationally infeasible.
• Currently Implemented: Documented in the application's security guidelines and backup setup instructions in docs/security/borg_setup.md.
• Missing Implementation: No automated passphrase strength check integrated directly into the application's Borg key generation process. No enforced policy or mechanism to ensure minimum passphrase complexity for Borg keys within the application's setup scripts or tools.

Mitigation Strategy: Regular Repository Checks with borg check

• Description:
  1. Implement a scheduled task to regularly execute the borg check --repository command. This is a core Borg command designed to verify the internal consistency and integrity of a Borg repository.
  2. Automate the execution of borg check using system scheduling tools like cron jobs or dedicated task schedulers. Frequency should be determined by backup criticality and repository size, but daily or weekly checks are recommended.
  3. Establish monitoring for the output of borg check. Configure alerts to be triggered immediately if borg check reports any errors, warnings, or inconsistencies within the Borg repository.
  4. Develop a documented incident response procedure to investigate and remediate any issues flagged by borg check in a timely manner. This includes steps for diagnosing the cause of corruption and potential data recovery if necessary.
• List of Threats Mitigated:
  • Data Corruption within Borg Repository (Medium Severity) - Detects and alerts on potential data corruption within the Borg repository caused by various factors such as hardware failures, software bugs in Borg or underlying storage systems, or unexpected interruptions during backup operations.
  • Backup Integrity Issues (Medium Severity) - Proactively ensures the backups remain consistent and restorable over time, reducing the risk of encountering unusable or incomplete backups during a critical data recovery scenario.
• Impact: Moderately reduces the risk of data corruption and backup integrity issues by providing early detection of repository problems, enabling timely intervention and preventing potential data loss or restoration failures.
• Currently Implemented: borg check is scheduled to run weekly on production backup servers using cron jobs. Basic alerting is configured to notify the operations team upon failures.
• Missing Implementation: borg check is not consistently scheduled for staging or development environments. Alerting and monitoring are not fully integrated into the central application monitoring system for comprehensive visibility and incident tracking. Automated remediation procedures for borg check failures are not yet defined.

Mitigation Strategy: Keep Borg Client Updated

• Description:
  1. Establish a robust process for regularly updating the Borg client software across all systems where it is installed and utilized. This includes application servers performing backups, dedicated backup servers, and developer machines involved in backup-related tasks.
  2. Actively monitor the official Borg project release channels, security mailing lists, and security advisory platforms for announcements of new Borg versions and security patches.
  3. Automate the Borg client update process wherever feasible. Leverage package managers (e.g., apt, yum, pip) or configuration management tools (e.g., Ansible, Chef, Puppet) to streamline and ensure consistent updates.
  4. Implement a testing phase for Borg client updates. Deploy updates to a non-production staging environment first to verify compatibility and identify any potential issues before rolling them out to production systems.
• List of Threats Mitigated:
  • Exploitation of Known Borg Vulnerabilities (High Severity) - Running outdated Borg client versions exposes the application to known security vulnerabilities that attackers could exploit to compromise the backup system or gain access to sensitive data.
  • Denial of Service (DoS) against Backup Processes (Medium Severity) - Certain vulnerabilities in older Borg versions might be exploitable to cause denial of service conditions, disrupting backup operations and potentially leading to data loss in the event of a system failure.
• Impact: Significantly reduces the risk of exploitation of known Borg vulnerabilities by ensuring that the Borg client software is consistently patched and running the latest stable and secure version.
• Currently Implemented: Automated Borg client updates are configured on production and staging servers using Ansible playbooks that execute weekly.
• Missing Implementation: No automated update process is in place for developer machines. Developers are currently responsible for manually updating Borg on their local systems, leading to potential version inconsistencies and delayed patching. Centralized tracking of Borg client versions across all environments is lacking, making it difficult to verify consistent patching.

Mitigation Strategy: Backup Verification and Test Restores using Borg Commands

• Description:
  1. Implement automated backup verification procedures that specifically utilize Borg commands. This should include using borg list to periodically check the metadata and contents of backups and borg extract to restore a representative subset of data to a temporary verification location.
  2. Schedule regular, automated test restores from Borg backups to a dedicated, isolated test environment. This process should simulate a real data recovery scenario.
  3. Document the detailed test restore procedure, including the specific Borg commands used, verification steps, and expected outcomes. Ensure this documentation is regularly reviewed and updated to reflect any changes in the backup process or infrastructure.
  4. Establish monitoring and logging for both backup verification and test restore processes. Track success and failure rates, and configure alerts to be triggered upon any failures or inconsistencies detected during verification or restoration attempts.
• List of Threats Mitigated:
  • Backup Failure (High Severity) - Undetected failures in the Borg backup process can lead to a situation where backups are incomplete, corrupted, or unusable, resulting in potential data loss during a disaster recovery event.
  • Data Corruption within Backups (Medium Severity) - Verification using Borg commands can help detect subtle data corruption issues within the backup archives that might not be identified by repository checks alone.
  • Restoration Failure (High Severity) - Ensures that the entire Borg backup and restoration pipeline is functioning correctly and that data can be reliably restored when needed, validating the effectiveness of the backup strategy.
• Impact: Significantly reduces the risk of backup and restoration failures by proactively validating the integrity of backups and the functionality of the restoration process using Borg's built-in capabilities. Increases confidence in data recoverability.
• Currently Implemented: Basic backup verification using borg list is performed automatically after each backup job and the output is logged for review.
• Missing Implementation: Automated test restores to a dedicated test environment using borg extract are not yet implemented. Comprehensive data integrity verification, such as restoring data and comparing checksums against the original source, is missing. Regularly scheduled, full-scale test restore drills are not currently performed.