attack-surface.md

Attack Surface Analysis for olivere/elastic

Attack Surface: NoSQL Injection (Elasticsearch Injection)

• Description: Attackers inject malicious Elasticsearch query syntax into user inputs that are then used to construct Elasticsearch queries via olivere/elastic.
• Elastic Contribution: olivere/elastic provides the interface to build and execute Elasticsearch queries. If developers don't use it securely (e.g., by concatenating strings instead of using parameterized queries), it facilitates injection vulnerabilities directly targeting Elasticsearch.
• Example: An application searches for products based on user-provided names. If the application directly uses user input in a QueryStringQuery without sanitization, an attacker could input name: "product) OR _exists_:field" to bypass intended search logic and potentially retrieve all documents from the Elasticsearch index.
• Impact: Data exfiltration, data manipulation, denial of service, potentially remote code execution (in older Elasticsearch versions with scripting enabled, less likely with direct olivere/elastic usage but still a concern if scripting is enabled and misused within Elasticsearch).
• Risk Severity: High to Critical
• Mitigation Strategies:
  • Parameterize Queries: Always use parameterized queries provided by olivere/elastic's fluent API. Avoid string concatenation when building queries to prevent direct injection into the Elasticsearch query structure.
  • Input Sanitization and Validation: Thoroughly sanitize and validate all user inputs before using them in Elasticsearch queries. Use allow-lists and escape special characters if necessary to prevent malicious syntax from being interpreted by Elasticsearch.
  • Principle of Least Privilege (Elasticsearch User): Grant the application's Elasticsearch user only the minimum necessary permissions to limit the impact of a successful injection attack.
  • Disable Scripting (If Possible): If scripting is not essential in Elasticsearch, disable it to reduce the risk of remote code execution vulnerabilities being exploited through injection.

Attack Surface: Insecure Elasticsearch Credentials Management

• Description: Elasticsearch credentials (username, password, API keys) required by olivere/elastic to connect are stored insecurely, making them accessible to attackers.
• Elastic Contribution: olivere/elastic requires credentials to authenticate and connect to Elasticsearch. Compromised credentials grant attackers direct access to the Elasticsearch cluster, bypassing any application logic.
• Example: Credentials are hardcoded directly in the application code that uses olivere/elastic, stored in plain text configuration files accessible to unauthorized users, or exposed in easily accessible environment variables without proper protection. An attacker gaining access to the application's codebase or environment can retrieve these credentials and directly access Elasticsearch.
• Impact: Full compromise of the Elasticsearch cluster, leading to complete data breaches, data manipulation, denial of service, and potential cluster takeover.
• Risk Severity: Critical
• Mitigation Strategies:
  • Secrets Management System: Utilize dedicated and secure secrets management systems like HashiCorp Vault, AWS Secrets Manager, or Azure Key Vault to store and manage Elasticsearch credentials. olivere/elastic can be configured to retrieve credentials from these systems programmatically.
  • Environment Variables (Securely Managed): If using environment variables, ensure they are properly protected within a secure environment and not easily accessible. Avoid logging or exposing them unnecessarily. Restrict access to the environment where these variables are set.
  • Principle of Least Privilege (Credentials): Use dedicated service accounts with minimal necessary permissions specifically for the application to connect to Elasticsearch. Avoid using administrative or overly privileged accounts.
  • Regular Credential Rotation: Implement a mandatory process for regularly rotating Elasticsearch credentials to limit the window of opportunity if credentials are compromised.

Attack Surface: Insufficient Elasticsearch Role-Based Access Control (RBAC)

• Description: Elasticsearch RBAC is not properly configured, granting the application's Elasticsearch user (used by olivere/elastic) excessive privileges within the Elasticsearch cluster.
• Elastic Contribution: olivere/elastic operates entirely within the permissions granted to the Elasticsearch user it uses for connection. Weak RBAC in Elasticsearch directly expands the attack surface accessible through olivere/elastic if the application or its credentials are compromised.
• Example: The application's Elasticsearch user is granted the superuser role or all privileges on indices it interacts with. If the application is compromised (e.g., through NoSQL injection or an application vulnerability), the attacker can leverage these excessive Elasticsearch privileges to perform actions far beyond the application's intended scope, such as deleting critical indices, accessing sensitive data unrelated to the application's function, or even manipulating cluster settings.
• Impact: Lateral movement within the Elasticsearch cluster, broader unauthorized data access, potential for significantly more extensive damage beyond the application's intended application scope.
• Risk Severity: High to Critical
• Mitigation Strategies:
  • Principle of Least Privilege (RBAC): Strictly adhere to the principle of least privilege when configuring Elasticsearch RBAC. Grant the application's Elasticsearch user only the absolute minimum necessary permissions required for its specific operations (e.g., read, write, index creation only on specific indices it needs to access).
  • Granular Role Definition: Define granular roles in Elasticsearch that precisely match the application's required actions. Avoid using broad, overly permissive roles.
  • Regular RBAC Audits and Reviews: Regularly audit and review Elasticsearch RBAC configurations to ensure they remain aligned with the principle of least privilege and the application's current needs. Remove any unnecessary or excessive permissions.
  • Role Separation: Create distinct roles for different application functionalities or components, each with its own narrowly scoped set of permissions, further limiting the potential impact of a compromise in one area.

Attack Surface: Direct Elasticsearch API Exposure

• Description: Elasticsearch API endpoints (ports 9200, 9300) are directly exposed to untrusted users or networks, bypassing application-level security controls and making Elasticsearch directly accessible.
• Elastic Contribution: While olivere/elastic is a client library used by the application, the underlying Elasticsearch API is the vulnerable target. Direct API exposure allows attackers to bypass the application and olivere/elastic entirely and interact directly with Elasticsearch using any Elasticsearch client or even raw HTTP requests.
• Example: Elasticsearch ports (9200, 9300) are left open to the public internet or are accessible from untrusted networks without robust access control mechanisms. Attackers can directly query Elasticsearch indices, attempt to manipulate data, exploit known Elasticsearch vulnerabilities, or launch denial-of-service attacks against the Elasticsearch cluster, completely bypassing the application and its intended security measures.
• Impact: Full, unrestricted access to Elasticsearch data and cluster functionality, potential for complete data breaches, data manipulation, deletion, cluster disruption, and even cluster takeover.
• Risk Severity: Critical
• Mitigation Strategies:
  • Network Segmentation (Mandatory): Isolate the Elasticsearch cluster within a highly secure network zone, behind robust firewalls. This is a fundamental security requirement.
  • Strict Firewall Rules: Configure firewalls to strictly restrict access to Elasticsearch ports (9200, 9300) allowing connections only from trusted networks and specific IP addresses (e.g., application servers). Deny all public internet access.
  • VPN or Bastion Host (for Admin Access): For administrative access to Elasticsearch from outside the secure network, use a VPN or a bastion host with strong multi-factor authentication. Never expose Elasticsearch directly to the public internet for administration.
  • Disable HTTP API (If Possible and Applicable): If the HTTP API is not absolutely necessary for your use case (e.g., if you only use the Java Transport Client or similar), consider disabling the HTTP API in Elasticsearch configuration to further reduce the attack surface. However, this is less common with olivere/elastic which uses HTTP.

Attack Surface: Denial of Service (DoS) via Malicious Queries

• Description: Attackers craft and send resource-intensive Elasticsearch queries, potentially through the application using olivere/elastic, that overload the Elasticsearch cluster, leading to performance degradation or a complete service outage.
• Elastic Contribution: olivere/elastic is the mechanism used by the application to execute queries against Elasticsearch. If the application allows users to influence query construction without proper validation or safeguards, attackers can leverage olivere/elastic to send deliberately malicious queries designed to exhaust Elasticsearch resources.
• Example: An attacker sends a highly complex wildcard query, a deeply nested aggregation, or a query targeting an extremely large index without proper filtering. These queries consume excessive CPU, memory, and I/O resources on the Elasticsearch cluster, causing it to slow down significantly or become completely unresponsive, impacting application availability and potentially other services relying on the same Elasticsearch cluster.
• Impact: Denial of service, impacting application availability, potentially leading to data loss if the cluster becomes unstable, and affecting other services dependent on the Elasticsearch cluster.
• Risk Severity: High
• Mitigation Strategies:
  • Query Complexity Limits (Elasticsearch Configuration): Implement query complexity limits and timeouts directly within Elasticsearch configuration to prevent resource-intensive queries from overwhelming the cluster. Configure limits on aggregations, script execution time, and other resource-intensive operations.
  • Query Analysis and Validation (Application Level): Analyze and validate user-generated queries at the application level before they are executed against Elasticsearch. Identify and block potentially malicious or overly complex queries based on predefined criteria or heuristics.
  • Rate Limiting (Application Level): Implement rate limiting on requests to Elasticsearch from the application to prevent query floods. Limit the number of queries that can be sent within a specific time frame, especially from individual users or IP addresses.
  • Resource Monitoring and Alerting (Elasticsearch Cluster): Continuously monitor Elasticsearch cluster performance and resource usage (CPU, memory, disk I/O). Set up proactive alerts for unusual resource consumption patterns that might indicate a DoS attack or other performance issues.
  • Circuit Breakers (Elasticsearch Configuration): Leverage Elasticsearch's built-in circuit breaker mechanisms to prevent runaway queries from crashing the cluster. Configure circuit breakers to trip and reject queries that exceed resource thresholds.