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threat-modeling.md

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Threat Model Analysis for ossec/ossec-hids

Threat: OSSEC Server Compromise

Description: An attacker gains administrative access to the central OSSEC server. This could be achieved by exploiting vulnerabilities in OSSEC software, weak credentials, or compromising the underlying operating system. Once compromised, the attacker can disable monitoring, manipulate rules, access sensitive logs and alerts, and potentially use the server as a pivot point to attack other systems. Impact: Complete loss of security monitoring across the environment, data breach of sensitive security logs and alerts, ability for attackers to operate undetected and mask malicious activity, potential for lateral movement and further compromise of the network. Affected OSSEC Component: OSSEC Server (ossec-authd, ossec-analysisd, ossec-dbd, ossec-remoted, etc.) and underlying operating system. Risk Severity: Critical Mitigation Strategies:

  • Regularly patch OSSEC server software and the underlying operating system to address known vulnerabilities.
  • Enforce strong password policies and implement multi-factor authentication for all administrative accounts accessing the OSSEC server.
  • Harden the OSSEC server operating system by disabling unnecessary services, applying security configurations, and using a firewall to restrict network access.
  • Implement network segmentation to isolate the OSSEC server within a secure network zone, limiting its exposure to potential attackers.
  • Conduct regular security audits and penetration testing of the OSSEC server and its environment to identify and remediate vulnerabilities.
  • Utilize intrusion detection/prevention systems (IDS/IPS) to monitor network traffic to and from the OSSEC server for suspicious activity.

Threat: OSSEC Agent Compromise

Description: An attacker gains root or administrative level access to a system running an OSSEC agent. This could be achieved through exploiting vulnerabilities in applications on the agent system, weak system security practices, or insider threats. With agent compromise, an attacker can stop the agent process, manipulate logs before they are sent to the server, or use the compromised system as a platform for further malicious activities while evading detection by OSSEC. Impact: Loss of security monitoring for the compromised system, potential for manipulated or deleted logs leading to missed security incidents, attackers can use the compromised agent system for lateral movement within the network, data exfiltration, or other malicious purposes without detection by OSSEC. Affected OSSEC Component: OSSEC Agent (ossec-agentd, logcollector, rootcheck, syscheck, etc.) and underlying operating system. Risk Severity: High Mitigation Strategies:

  • Regularly patch OSSEC agent software and the underlying operating system to address known vulnerabilities.
  • Implement strong system security practices on all systems running OSSEC agents, including least privilege principles, regular security audits, and robust access controls.
  • Deploy host-based intrusion detection/prevention systems (HIDS/HIPS) in addition to OSSEC on critical systems to provide layered security.
  • Continuously monitor the status and connectivity of OSSEC agents from the server to ensure agents are running and reporting correctly.
  • Implement secure configuration management practices for agent deployments to ensure consistent and secure configurations across all agents.

Threat: OSSEC Database Compromise

Description: An attacker gains unauthorized access to the database used by the OSSEC server to store alerts, logs, and configuration data. This could be achieved through SQL injection vulnerabilities (if using an external database), weak database credentials, or insecure database configuration. Access to the database allows attackers to read sensitive security information, tamper with historical records, and potentially gain insights into the security posture of the monitored environment. Impact: Data breach of sensitive security logs and alerts, potential exposure of confidential information about monitored systems and security incidents, ability for attackers to tamper with security records and potentially cover their tracks, potential for compliance violations due to data breaches. Affected OSSEC Component: OSSEC Database (e.g., file-based database or external database system) and database access components (ossec-dbd). Risk Severity: High Mitigation Strategies:

  • Secure the OSSEC database with strong authentication and authorization mechanisms, ensuring only authorized processes and users can access it.
  • Regularly patch the database system if using an external database to address known vulnerabilities.
  • Implement strict database access controls, limiting access to the database to only necessary users and processes with the principle of least privilege.
  • Encrypt the database at rest and in transit to protect sensitive data even if unauthorized access is gained.
  • Regularly backup the OSSEC database to ensure data recoverability in case of compromise or data loss.

Threat: Rule Set Manipulation

Description: An attacker gains the ability to modify the OSSEC rule sets, which define how events are analyzed and alerts are generated. This could be achieved by compromising the OSSEC server or exploiting vulnerabilities in rule management processes. By manipulating rules, attackers can disable detection of specific attack patterns, introduce false positives to overwhelm security teams, or create backdoors in the rule logic to bypass detection. Impact: Significant degradation or complete failure of OSSEC's threat detection capabilities, increased alert fatigue for security teams due to false positives, potential for critical malicious activity to go undetected, weakening of the overall security posture and increased risk of successful attacks. Affected OSSEC Component: OSSEC Analysis Engine (ossec-analysisd), Rule Files (XML rule files). Risk Severity: High Mitigation Strategies:

  • Restrict access to OSSEC rule files and rule management processes to only authorized security personnel.
  • Implement version control for OSSEC rule sets and meticulously track all changes made to rules, including who made the changes and when.
  • Regularly review and audit OSSEC rule sets for accuracy, effectiveness, and any signs of unauthorized or malicious modifications.
  • Use a secure and controlled rule update mechanism, verifying the integrity and authenticity of rule updates before deployment.
  • Consider using a centralized rule management system with robust access controls and audit logging to manage and maintain rule sets securely.

Threat: Configuration File Manipulation

Description: An attacker gains unauthorized access to modify OSSEC configuration files, either on the server or agents. This could be achieved through system compromise or exploiting vulnerabilities in configuration management processes. By altering configuration files, attackers can disable specific OSSEC functionalities, change logging levels to reduce detection capabilities, redirect alerts to attacker-controlled systems, or weaken security settings, effectively undermining OSSEC's effectiveness. Impact: Significant reduction in OSSEC's security effectiveness, loss of specific monitoring capabilities leading to blind spots in security coverage, potential for critical alerts to be missed or redirected, weakening of the overall security posture and increased vulnerability to attacks, potential for compliance violations if security controls are disabled. Affected OSSEC Component: OSSEC Server and Agent Configuration Files (ossec.conf, agent.conf), Configuration Management Modules. Risk Severity: High Mitigation Strategies:

  • Restrict access to OSSEC configuration files to only authorized personnel and processes, using file system permissions and access control lists.
  • Implement file integrity monitoring for critical OSSEC configuration files to detect any unauthorized modifications.
  • Utilize secure configuration management practices and tools to manage OSSEC configurations in a controlled and auditable manner.
  • Regularly review and audit OSSEC configuration files for any unauthorized or unexpected changes.
  • Implement version control for configuration files to track changes and facilitate rollback to previous secure configurations if necessary.

Threat: Denial of Service against OSSEC Server

Description: An attacker attempts to overload the OSSEC server with excessive traffic or requests, aiming to exhaust its resources and make it unresponsive or unavailable. This could be achieved through network flooding attacks, resource exhaustion attacks targeting server processes, or exploiting application-level vulnerabilities. A successful DoS attack against the OSSEC server disrupts security monitoring for the entire environment. Impact: Complete loss of real-time security monitoring across all systems, delayed or missed security alerts, creation of blind spots in security coverage allowing malicious activity to go undetected, disruption of security operations and incident response capabilities, potential for cascading failures if security monitoring is critical for other security systems. Affected OSSEC Component: OSSEC Server (ossec-authd, ossec-analysisd, ossec-remoted, etc.), Network Infrastructure. Risk Severity: High Mitigation Strategies:

  • Implement network-level Denial of Service (DoS) protection measures, such as firewalls with rate limiting, intrusion prevention systems (IPS) with DoS attack detection, and traffic filtering.
  • Harden the OSSEC server operating system and applications against DoS attacks by applying security patches, optimizing resource utilization, and configuring appropriate resource limits.
  • Continuously monitor OSSEC server resource utilization (CPU, memory, network bandwidth) and performance to detect potential DoS attacks early.
  • Implement load balancing or clustering for the OSSEC server infrastructure if necessary to distribute load and improve resilience against DoS attacks.
  • Ensure sufficient server resources (CPU, memory, network bandwidth) are allocated to the OSSEC server to handle expected load and potential traffic spikes during attacks.