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attack-surface.md

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Attack Surface Analysis for collectiveidea/delayed_job

Attack Surface: 1. YAML Deserialization Vulnerabilities

  • Description: Exploitation of insecure YAML deserialization to execute arbitrary code.
  • Delayed Job Contribution: Delayed Job often uses YAML to serialize job handlers and arguments, making it vulnerable if insecure deserialization methods are used.
  • Example: An attacker injects a malicious YAML payload as a job argument. When a worker processes this job, YAML.load deserializes the payload, triggering code execution on the server.
  • Impact: Remote Code Execution (RCE), full server compromise, data breach, denial of service.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Use YAML.safe_load: Replace YAML.load with YAML.safe_load to limit deserialization to safer data types.
    • Alternative Serialization: Consider using JSON or other safer serialization formats instead of YAML for job data.
    • Input Validation: Sanitize and validate job arguments before serialization to prevent injection of malicious YAML.

Attack Surface: 2. Object Injection through Deserialization

  • Description: Exploiting vulnerabilities in custom classes used as job arguments during deserialization, even with YAML.safe_load.
  • Delayed Job Contribution: Delayed Job allows serialization of custom objects as job arguments. If these objects have unsafe methods triggered during deserialization, it can be exploited.
  • Example: A job argument is an object of a custom class with a vulnerable initialize method. Deserializing this object during job processing triggers the vulnerable method, leading to unintended actions or code execution.
  • Impact: Potential Remote Code Execution (RCE), data manipulation, privilege escalation, denial of service, depending on the vulnerability in the custom class.
  • Risk Severity: High
  • Mitigation Strategies:
    • Audit Custom Classes: Thoroughly review custom classes used as job arguments for potential vulnerabilities in initialize or other methods called during deserialization.
    • Whitelist Allowed Classes: If using custom objects, implement a whitelist of allowed classes for deserialization to prevent unexpected object instantiation.
    • Simplify Job Arguments: Prefer serializing simple data types (strings, integers) and reconstruct complex objects within the job execution context, avoiding object serialization where possible.

Attack Surface: 3. Unsafe Handling of Job Arguments (Command/SQL Injection)

  • Description: Improper validation and sanitization of job arguments leading to injection vulnerabilities when used in commands or database queries.
  • Delayed Job Contribution: Delayed Job passes arguments to job methods. If these arguments are not handled securely within the job's logic, it creates an injection attack surface.
  • Example: A job takes a filename as an argument and uses it directly in a shell command like system("convert #{filename} output.png"). An attacker injects a malicious filename like ; rm -rf / ;. This leads to command injection and potential system compromise. Similarly, unsanitized arguments in SQL queries can lead to SQL injection.
  • Impact: Command Injection, SQL Injection, Remote Code Execution (RCE), data breach, data manipulation, denial of service.
  • Risk Severity: High
  • Mitigation Strategies:
    • Input Validation and Sanitization: Strictly validate and sanitize all job arguments before using them in any operations.
    • Parameterized Queries: Use parameterized queries or ORM features for database interactions to prevent SQL injection.
    • Secure Command Execution: Avoid constructing shell commands from job arguments directly. If necessary, use secure command execution methods and carefully escape arguments using libraries designed for this purpose.

Attack Surface: 4. Unprotected Job Queue Access

  • Description: Unauthorized access or manipulation of the Delayed Job queue, leading to malicious job insertion, deletion, or modification.
  • Delayed Job Contribution: Delayed Job relies on a database queue. If access to this database or management interfaces is not properly secured, it becomes an attack vector.
  • Example: An attacker gains access to the database used by Delayed Job (e.g., through a web application vulnerability or weak database credentials). They insert malicious jobs designed for YAML deserialization exploits, delete legitimate jobs causing denial of service, or modify existing jobs to alter application behavior.
  • Impact: Malicious Job Execution, Remote Code Execution (RCE), Denial of Service (DoS), data integrity compromise, application malfunction.
  • Risk Severity: High
  • Mitigation Strategies:
    • Secure Database Access: Restrict database access to the Delayed Job queue. Use strong, unique credentials and network firewalls to limit access.
    • Authorization for Queue Management: Implement robust authentication and authorization for any interfaces (e.g., admin panels) that allow managing or viewing the job queue.
    • Database Access Control: Utilize database access control mechanisms to limit the permissions of the application user accessing the queue to the minimum required.