threat-modeling.md

Threat Model Analysis for mengto/spring

Threat: In-Memory Code Modification

• Description: An attacker with local access (compromised account, malware) or a compromised dependency injects malicious code directly into the running Spring process. Because Spring preloads and keeps the Rails application running in memory, this injected code persists across requests, creating a highly effective and persistent backdoor. The attacker gains full control over the application's behavior, allowing data theft, manipulation, or further system compromise.
  • Impact:
    • Complete and persistent compromise of application integrity.
    • Data breaches (reading, modifying, deleting sensitive data).
    • Potential for lateral movement to other systems.
    • Long-term, undetected backdoor.
  • Affected Spring Component: Spring::ApplicationManager (and, by extension, all loaded Rails application code). This is the core component responsible for managing the preloaded application instance in memory.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Mandatory Regular Restarts: Implement a strict policy of restarting Spring frequently (e.g., daily, after significant code changes, after gem updates). This is the primary defense, clearing in-memory modifications. Use spring stop followed by restarting the Rails server.
    • File Integrity Monitoring (FIM): Use FIM tools to monitor critical application files. While the attack is in-memory, changes to the source files should still trigger alerts.
    • Rigorous Dependency Management: Employ bundler-audit and keep all dependencies (including Spring) meticulously updated. Use a Gemfile.lock for consistent dependency versions.
    • Least Privilege Principle: Run Spring (and the Rails app) with the absolute minimum necessary privileges. Never run as root.
    • Code Reviews (Preventative): Thorough code reviews help identify vulnerabilities that could be exploited for code injection.

Threat: Unauthorized Command Execution via Spring's Client-Server

• Description: Spring uses a client-server model. The spring command (client) communicates with the background Spring server process. An attacker who compromises the communication channel (e.g., local man-in-the-middle, social engineering to run a malicious command) can execute arbitrary commands within the context of the preloaded application. This bypasses typical file-based protections.
  • Impact:
    • Arbitrary code execution within the application, leading to data breaches, system compromise, or other malicious actions.
    • Similar impact to in-memory modification, but potentially easier to exploit if the communication is not secured.
  • Affected Spring Component: Spring::Client and Spring::Server. These components manage the communication between the spring command and the background process.
  • Risk Severity: High
  • Mitigation Strategies:
    • Restrict Socket Permissions: Ensure the local socket file used for Spring's communication has highly restrictive permissions, preventing unauthorized access.
    • Developer Awareness Training: Educate developers about the risks of running untrusted commands or scripts, especially those interacting with Spring.
    • Process Monitoring: Actively monitor running processes for suspicious activity related to Spring, including unexpected child processes.
    • Regular Spring Restarts: Frequent restarts (as with in-memory modification) limit the window of opportunity for persistent command execution.

Threat: Vulnerability in Spring Leading to Code Execution

• Description: A vulnerability within Spring itself (e.g., buffer overflow, command injection) is exploited by an attacker to gain code execution on the developer's machine. This is a direct threat stemming from a flaw in Spring's code.
  • Impact:
    • Code execution on the developer's machine, potentially leading to complete system compromise. The severity depends on the vulnerability and Spring's privileges.
  • Affected Spring Component: Any component of Spring could be vulnerable.
  • Risk Severity: High (Potentially Critical, depending on the vulnerability)
  • Mitigation Strategies:
    • Immediate Updates: Keep Spring absolutely up-to-date. Use bundle update spring regularly and immediately upon the release of security patches.
    • Least Privilege: Run Spring with the minimum necessary privileges. Never run as root. This limits the impact of a successful exploit.
    • Monitor Security Advisories: Actively monitor for security advisories and vulnerability reports related to Spring. Subscribe to relevant mailing lists or security feeds.
    • (Optional) Security Audits: If resources permit, consider periodic security audits of Spring's codebase.