Skip to content

Latest commit

 

History

History
58 lines (48 loc) · 6.33 KB

attack-surface.md

File metadata and controls

58 lines (48 loc) · 6.33 KB

Attack Surface Analysis for greenrobot/eventbus

Attack Surface: Malicious Event Injection

  • 1. Malicious Event Injection

    • Description: Attackers craft and inject malicious events into the EventBus to trigger unintended actions or exploit vulnerabilities in subscribers. This is the primary attack vector against EventBus.
    • How EventBus Contributes: EventBus provides the mechanism for event injection. Its decoupled nature (senders don't know receivers) facilitates this attack. The ability to post events from anywhere within the application (or externally if misconfigured) is the core issue.
    • Example: An attacker injects a custom "GrantAdminPrivilegesEvent" with a fabricated user ID, bypassing authentication and gaining administrative access. Another example: injecting an event that triggers a sensitive function (e.g., "DeleteUserAccountEvent") with malicious parameters.
    • Impact:
      • Bypass security controls (authentication, authorization).
      • Execute arbitrary code (if subscribers have vulnerabilities exploitable via event data).
      • Data modification, deletion, or exfiltration.
      • Privilege escalation.
      • Denial of service (by triggering resource-intensive operations or causing crashes).
    • Risk Severity: Critical
    • Mitigation Strategies:
      • Strictly Typed Events: Use specific event classes (e.g., AdminPrivilegeGrantEvent with well-defined fields) instead of generic Object or String events. This limits the attacker's ability to inject arbitrary data.
      • Rigorous Input Validation: Subscribers must thoroughly validate all data within received events before any action is taken. This includes type checks, range checks, format validation, and any other relevant checks. Treat all event data as untrusted input.
      • Sender Verification (Complex, Use with Caution): If the sender's identity is absolutely critical for security, consider including and verifying sender information within the event itself. However, this adds significant complexity and potential for errors. It's often better to rely on strong typing and input validation.
      • Least Privilege for Subscribers: Subscribers should only be registered to receive the absolute minimum set of events they require. Avoid subscribing to broad event types (e.g., subscribing to Object). This limits the impact of a compromised subscriber.
      • Internal EventBus Only: Do not expose the EventBus instance externally unless there is an extremely compelling reason and with extreme security precautions. The EventBus should be an internal communication mechanism.

Attack Surface: Event Eavesdropping/Interception

  • 2. Event Eavesdropping/Interception

    • Description: Attackers intercept events as they travel through the EventBus to gain access to sensitive data contained within the event payloads.
    • How EventBus Contributes: EventBus acts as the conduit for event communication. If an attacker can gain access to this conduit (e.g., through memory inspection or hooking), they can observe all event traffic.
    • Example: An attacker intercepts an event carrying a user's unencrypted session token or API key, allowing them to impersonate the user or access protected resources.
    • Impact:
      • Data leakage (sensitive user information, authentication credentials, internal application data).
      • Loss of confidentiality.
      • Potential for further attacks based on the intercepted data.
    • Risk Severity: High
    • Mitigation Strategies:
      • Minimize Sensitive Data in Events: The best mitigation is to avoid sending sensitive data directly within events. Instead, send identifiers or references that can be used to securely retrieve the data from a trusted source (e.g., a secure data store).
      • Encryption (Only When Absolutely Necessary): If sending sensitive data directly in events is unavoidable, encrypt the event payload. This introduces key management overhead and complexity, so only use it when strictly required. Consider the performance impact.
      • Avoid using EventBus for highly sensitive data transfer: If you are dealing with extremely sensitive data, consider using a more secure communication mechanism than EventBus.

Attack Surface: Subscriber Hijacking

  • 3. Subscriber Hijacking

    • Description: Attackers register malicious subscribers to the EventBus or modify the code of existing, legitimate subscribers to intercept events or perform unauthorized actions.
    • How EventBus Contributes: EventBus's subscriber registration mechanism is the attack point. If this mechanism is not properly secured, attackers can inject their own subscribers.
    • Example: An attacker injects code that registers a new subscriber to log all events of type "TransactionEvent" to a remote server, exfiltrating financial data. Alternatively, they might modify an existing subscriber to perform additional, malicious actions upon receiving a specific event.
    • Impact:
      • Data leakage (if the malicious subscriber intercepts sensitive events).
      • Unauthorized actions triggered by the malicious subscriber.
      • Denial of service (if the malicious subscriber consumes excessive resources).
      • Subversion of application logic.
    • Risk Severity: High
    • Mitigation Strategies:
      • Strictly Controlled Subscriber Registration: Centralize and tightly control the process of registering subscribers. Avoid dynamic subscriber registration based on untrusted input or external sources. Ideally, subscribers should be registered at application startup in a well-defined and secure manner.
      • Code Integrity Checks: Implement mechanisms to detect unauthorized modifications to subscriber code. This can involve code signing, checksum verification, or other integrity checks.
      • Runtime Application Self-Protection (RASP): Consider using RASP tools to detect and prevent code injection and modification at runtime. This provides an additional layer of defense.