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attack-surface.md

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Attack Surface Analysis for stackexchange/stackexchange.redis

Attack Surface: Connection String Exposure and Misconfiguration

  • Description: Sensitive information like Redis server addresses, ports, and passwords are exposed or misconfigured, allowing unauthorized access to the Redis instance.
  • stackexchange.redis Contribution: stackexchange.redis requires a connection string to establish a connection to the Redis server. Insecure management or exposure of this connection string directly leads to this vulnerability when using the library.
  • Example: A connection string containing a hardcoded password (redis-server:6379,password=WeakPassword) is embedded directly in the application's source code, which is then inadvertently committed to a public version control repository. An attacker discovers this repository, retrieves the connection string, and gains unauthorized access to the Redis server.
  • Impact: Data breach, data manipulation, denial of service, potential lateral movement within the infrastructure if the Redis server is compromised.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Secure Configuration Management: Utilize secure configuration management systems (e.g., HashiCorp Vault, Azure Key Vault, AWS Secrets Manager) or environment variables to store and manage connection strings securely.
    • Principle of Least Privilege: Employ dedicated Redis users with minimal necessary permissions instead of relying on default or overly permissive user accounts.
    • Regular Security Audits: Conduct periodic audits of application configurations and deployment processes to ensure connection strings are not inadvertently exposed or insecurely stored.
    • Encryption at Rest and in Transit: Encrypt connection strings when stored and consider using TLS/SSL encryption for communication between stackexchange.redis and the Redis server.

Attack Surface: Redis Command Injection

  • Description: User-controlled input is directly incorporated into Redis commands without proper sanitization or parameterization, enabling attackers to execute arbitrary Redis commands.
  • stackexchange.redis Contribution: stackexchange.redis provides methods like Database.Execute() that allow developers to send raw Redis commands. If these methods are used to construct commands using unsanitized user input, it directly facilitates command injection vulnerabilities.
  • Example: Application code constructs a Redis command to retrieve data using a key derived from user input: db.Execute("GET", userInput). If userInput is maliciously crafted as key\r\nCONFIG GET *\r\n, the Redis server might execute both GET key and CONFIG GET *, potentially exposing sensitive server configuration details to the attacker.
  • Impact: Data manipulation, data deletion, unauthorized access to data, potential denial of service, in severe cases, potential for remote code execution if vulnerable Redis modules are enabled or through Lua scripting vulnerabilities.
  • Risk Severity: High to Critical (depending on the application's functionality and the potential for exploiting injected commands).
  • Mitigation Strategies:
    • Parameterization and Prepared Statements: Utilize parameterized commands or higher-level abstraction methods provided by stackexchange.redis (like StringGet, HashSet, etc.) which handle input sanitization and parameterization internally, preventing direct command injection.
    • Strict Input Validation and Sanitization: Implement rigorous input validation and sanitization for all user-provided data before incorporating it into Redis commands. Whitelist allowed characters and patterns, and escape or reject invalid input.
    • Principle of Least Privilege (Redis side): Configure Redis users with minimal necessary permissions to limit the impact of potential command injection. Disable or rename dangerous commands in redis.conf if they are not required by the application.
    • Code Review and Security Testing: Conduct thorough code reviews and penetration testing to identify and remediate potential command injection vulnerabilities in application code that interacts with stackexchange.redis.

Attack Surface: Denial of Service (DoS) through Connection Exhaustion

  • Description: Attackers exploit application logic or misconfigurations to exhaust Redis server or client connection resources, leading to denial of service for legitimate users.
  • stackexchange.redis Contribution: stackexchange.redis manages connection pooling. Improper configuration of the connection pool or application logic that leads to excessive connection requests or leaks can directly contribute to connection exhaustion DoS attacks when using this library.
  • Example: An attacker repeatedly triggers an application endpoint that, due to a coding flaw, opens a new ConnectionMultiplexer instance for each request instead of reusing an existing one. This rapid creation of connections exhausts the Redis server's connection limit or the application's resources, preventing legitimate requests from being processed and causing a denial of service.
  • Impact: Application downtime, service unavailability, business disruption, and potential resource exhaustion on the Redis server.
  • Risk Severity: High
  • Mitigation Strategies:
    • Optimize Connection Pooling Configuration: Carefully configure stackexchange.redis connection pooling settings (e.g., PoolSize, MinPoolSize, MaxPoolSize, IdleTimeOut) to align with application needs and Redis server capacity.
    • Connection Reuse and Management: Ensure application code reuses ConnectionMultiplexer instances effectively and avoids creating unnecessary new connections. Implement proper connection management practices, including closing connections when they are no longer needed (though connection pooling generally handles this).
    • Rate Limiting and Request Throttling: Implement rate limiting on application endpoints that interact with Redis to prevent malicious actors from overwhelming the system with connection requests.
    • Resource Monitoring and Alerting: Monitor Redis server and application connection metrics (e.g., connection count, connection errors) to detect and respond to potential connection exhaustion issues proactively.
    • Timeout Configuration: Configure appropriate timeouts in stackexchange.redis (e.g., connectTimeout, syncTimeout) to prevent long-hanging connection attempts from consuming resources indefinitely.

Attack Surface: Pub/Sub Channel Security (if using Pub/Sub features)

  • Description: Lack of proper authorization or access control on Redis Pub/Sub channels allows unauthorized users to subscribe to sensitive channels or publish malicious messages, disrupting application functionality or leaking data.
  • stackexchange.redis Contribution: stackexchange.redis provides APIs for utilizing Redis Pub/Sub functionality (e.g., GetSubscriber(), Subscribe(), Publish()). If these features are used without implementing adequate security measures, it directly contributes to vulnerabilities related to unauthorized access and manipulation of Pub/Sub channels.
  • Example: An application uses a Pub/Sub channel named critical-alerts to broadcast sensitive operational alerts. If this channel is publicly accessible without authentication or authorization checks implemented in the application using stackexchange.redis, an attacker can subscribe to it and intercept confidential alerts, or publish fake alerts to disrupt operations or spread misinformation.
  • Impact: Data breach, information leakage, disruption of application functionality, message spoofing, potential for manipulation of application state based on malicious messages.
  • Risk Severity: High (depending on the sensitivity of data transmitted via Pub/Sub and the impact of malicious messages).
  • Mitigation Strategies:
    • Application-Level Authentication and Authorization: Implement application-level authentication and authorization mechanisms to control access to Pub/Sub channels. Verify user permissions before allowing subscription or publishing to sensitive channels.
    • Channel Access Control Lists (ACLs) in Redis (Redis 6+): Leverage Redis Access Control Lists (ACLs) introduced in Redis 6 and later versions to restrict access to specific channels based on user roles and permissions directly at the Redis server level.
    • Secure Channel Naming Conventions: Use non-predictable and less guessable channel names to make it harder for unauthorized users to discover and subscribe to sensitive channels.
    • Encryption of Sensitive Data: Encrypt sensitive data before publishing it to Pub/Sub channels to protect confidentiality even if unauthorized access to the channel is gained.
    • Input Validation and Sanitization (Published Messages): Validate and sanitize messages published to Pub/Sub channels to prevent injection attacks or the propagation of malicious data within the application.