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attack-surface.md

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Attack Surface Analysis for nationalsecurityagency/skills-service

Attack Surface: 1. Malicious Skill Injection

  • Description: Attackers inject malicious code or commands through the skill definition mechanism. This is the core attack vector, inherent to the service's design.
    • How skills-service contributes: The service's primary function is to execute user-defined skills, making it inherently vulnerable to malicious input. This is a direct consequence of the service's purpose.
    • Example:
      • A skill definition includes a command to execute a shell script: command: "bash /tmp/malicious.sh".
      • A skill definition uses a templating feature to access system environment variables: description: "User info: {{ system.env.SECRET_KEY }}".
      • A skill definition attempts to write to a restricted file: output_file: "/etc/passwd".
    • Impact: Remote Code Execution (RCE), data exfiltration, system compromise, privilege escalation.
    • Risk Severity: Critical
    • Mitigation Strategies:
      • Strict Input Validation: Implement a whitelist-based approach, allowing only specific, pre-approved commands, functions, and data structures within skill definitions. Reject any input that doesn't conform to the whitelist. This is paramount.
      • Sandboxing: Execute skills within a highly restricted environment (e.g., a container with minimal privileges, a chroot jail, or a dedicated virtual machine). Limit access to the file system, network, and system calls severely. Use technologies like seccomp (Secure Computing Mode) to restrict system calls at the kernel level.
      • Code Review: Mandatory, rigorous code review of all skill definitions before deployment, especially if submitted by untrusted users. This is a critical human-in-the-loop control.
      • Language Restrictions: If feasible, use a restricted, domain-specific language (DSL) for skill definitions that inherently limits expressiveness and prevents arbitrary code execution. Avoid general-purpose scripting languages.
      • Output Encoding/Escaping: If skill results are displayed or used elsewhere, ensure proper output encoding/escaping to prevent secondary injection vulnerabilities (e.g., XSS).

Attack Surface: 2. Resource Exhaustion (Denial of Service)

  • Description: Attackers craft skill definitions designed to consume excessive system resources, leading to a denial of service. This is a direct attack on the service's execution capabilities.
    • How skills-service contributes: The service executes skills, which can directly consume arbitrary amounts of resources if not limited. This is an inherent risk of executing user-provided code.
    • Example:
      • A skill definition contains an infinite loop: while true; do echo "looping"; done.
      • A skill definition allocates a huge array: data: [1] * 1000000000.
      • A skill definition makes numerous network requests in a tight loop.
      • A skill definition creates many temporary files without deleting them.
    • Impact: Denial of Service (DoS), system instability, unavailability of the service.
    • Risk Severity: High
    • Mitigation Strategies:
      • Resource Limits: Strictly enforce resource limits on all skill executions. This includes CPU time, memory usage, disk space, network bandwidth, and the number of processes. Use containerization (e.g., Docker, with resource limits) or system-level tools (e.g., ulimit, cgroups) for enforcement.
      • Timeouts: Implement mandatory timeouts for all skill executions to prevent them from running indefinitely.
      • Rate Limiting: Limit the rate at which users can submit or execute skills to prevent abuse. This is a crucial preventative measure.
      • Monitoring and Alerting: Continuously monitor resource usage and set up immediate alerts for potential DoS attacks (e.g., exceeding resource thresholds).

Attack Surface: 3. Skill Definition Tampering

  • Description: Attackers gain unauthorized access to modify existing skill definitions, injecting malicious code or altering their behavior. This directly targets the service's stored skill data.
    • How skills-service contributes: The service relies on stored skill definitions, which become a direct target for tampering. The service's functionality depends on the integrity of these definitions.
    • Example:
      • An attacker gains access to the database and modifies a legitimate skill definition to include a malicious command.
      • An attacker exploits a vulnerability in the API to overwrite a skill definition file.
    • Impact: Similar to Malicious Skill Injection (RCE, data exfiltration, etc.), but with the added risk of affecting existing, previously trusted skills. This can be a covert attack.
    • Risk Severity: High
    • Mitigation Strategies:
      • Access Control: Implement strict access control to the storage location of skill definitions (database, file system, etc.). Only authorized users and services should have write access. This is fundamental.
      • Integrity Checks: Use cryptographic hashes (e.g., SHA-256) or digital signatures to verify the integrity of skill definitions. Detect any unauthorized modifications immediately.
      • Auditing: Log all changes to skill definitions, including who made the change and when. This provides an audit trail for investigation.
      • Version Control: Use a version control system (e.g., Git) to track changes to skill definitions and allow for rollback to previous, known-good versions.

Attack Surface: 4. API Abuse (Directly Related to Skills)

  • Description: Attackers exploit vulnerabilities in the API specifically to submit malicious skills or trigger unauthorized skill executions. This focuses on API calls directly related to the core skill functionality.
    • How skills-service contributes: The service exposes an API for managing and executing skills, and this API becomes a direct attack surface for manipulating the core functionality.
    • Example:
      • An attacker bypasses authentication and submits malicious skill definitions through the API.
      • An attacker uses the API to trigger excessive skill executions, leading to a DoS.
      • An attacker uses API to list all available skills and their definitions.
    • Impact: Unauthorized access, data breaches, DoS, system compromise (through malicious skill execution).
    • Risk Severity: High
    • Mitigation Strategies:
      • Strong Authentication: Implement robust authentication for all API endpoints related to skill submission and execution. Use strong passwords, multi-factor authentication (MFA), or API keys/tokens with secure management.
      • Authorization (RBAC/ABAC): Enforce fine-grained authorization using Role-Based Access Control (RBAC) or Attribute-Based Access Control (ABAC). Restrict access to specific API functions (e.g., submitting skills, executing skills) and resources (e.g., specific skill types) based on user roles and attributes.
      • Input Validation: Rigorously validate all API inputs related to skill definitions and execution parameters. Use a whitelist approach whenever possible. This is crucial for preventing injection attacks through the API.
      • Rate Limiting: Limit the rate of API requests, especially for skill submission and execution endpoints, to prevent abuse and DoS attacks.
      • Secure Communication (TLS): Use TLS/SSL with strong ciphers and protocols to encrypt all API communication.