threat-modeling.md

Threat Model Analysis for gui-cs/terminal.gui

Threat: Terminal Escape Sequence Injection (Command Execution)

• Threat: Terminal Escape Sequence Injection (Command Execution)

  • Description: An attacker provides malicious input containing terminal escape sequences (e.g., OSC 52 or other terminal-specific sequences) that are not properly sanitized by the application. The attacker crafts the input to be passed through terminal.gui and ultimately interpreted by the underlying terminal emulator. The goal is to execute arbitrary commands on the host system. An attacker might enter a seemingly harmless string into a TextField, but that string contains hidden escape sequences that, when rendered, instruct the terminal to run a command.
  • Impact: Complete system compromise. The attacker gains the ability to execute arbitrary code with the privileges of the user running the application. This could lead to data theft, system modification, installation of malware, or lateral movement within a network.
  • Affected Component: Primarily TextView, TextField, Label, and any component that displays user-provided or untrusted text. The vulnerability lies in how these components output text to the terminal, not necessarily within the components themselves. The underlying issue is the interaction between terminal.gui's output and the terminal emulator's interpretation of that output.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Strict Output Encoding: Before displaying any text originating from user input or untrusted sources, meticulously encode or escape all characters that could be interpreted as part of an escape sequence. This is the primary defense. A whitelist approach (allowing only a very limited set of safe characters) is strongly recommended for output. Do not rely on terminal.gui to perform this encoding automatically. Use a dedicated encoding library designed for terminal output sanitization.
    • Input Validation (Secondary): While output encoding is the primary defense, robust input validation is still crucial. Validate input length, character types, and format before it's ever used by terminal.gui. This helps prevent other attacks and reduces the attack surface.
    • Terminal Emulator Hardening: Configure the terminal emulator to disable potentially dangerous features, such as OSC 52 (clipboard manipulation), if they are not strictly necessary. This is a defense-in-depth measure.
    • Use a Secure Terminal Emulator: Encourage users to use a modern, well-maintained terminal emulator that is known to be resistant to escape sequence injection vulnerabilities.
    • Least Privilege: Run the application with the minimum necessary privileges.

Threat: Input Validation Bypass (Application Logic Manipulation)

• Threat: Input Validation Bypass (Application Logic Manipulation)

  • Description: An attacker crafts input that bypasses terminal.gui's built-in input validation (e.g., length limits, allowed characters) or the application's own validation logic. This could involve using special characters, control codes, or exploiting edge cases in the validation routines. The attacker aims to manipulate the application's behavior by providing unexpected input. For example, if a TextField is used to enter a filename, the attacker might try to inject path traversal characters (../) to access files outside the intended directory. If the application then uses this unsanitized filename to execute a system command, this becomes a high-severity threat.
  • Impact: Varies depending on how the manipulated input is used. If the bypassed input is used in security-sensitive operations (e.g., constructing file paths, system commands, or database queries), the impact can be high, potentially leading to unauthorized file access, data corruption, or even code execution.
  • Affected Component: TextField, Autocomplete, Dialog (input fields), ListView (if user input affects item selection), and any component that accepts user input.
  • Risk Severity: High
  • Mitigation Strategies:
    • Multi-Layered Input Validation: Implement input validation at multiple levels:
      • terminal.gui Level: Use terminal.gui's built-in validation features (e.g., MaxLength property of TextField) as a first line of defense.
      • Application Level: Implement additional, more rigorous validation logic before using the input in any application-specific operations. This should include checks for length, allowed characters (whitelist approach is preferred), data type, and format. Specifically, check for and reject any characters that could be used for path traversal, command injection, or other security-relevant manipulations.
      • Backend Validation: If the application interacts with a backend system, perform validation on the backend as well. Never trust client-side validation alone.
    • Sanitize Input: After validation, sanitize the input by escaping or removing any potentially harmful characters.
    • Use Parameterized Queries (if applicable): If the input is used to construct database queries, use parameterized queries or prepared statements to prevent SQL injection.
    • Use Safe APIs: If the input is used to construct file paths or system commands, use safe APIs that prevent injection vulnerabilities (e.g., APIs that accept path components separately rather than as a single string).
    • Regular Expressions (Carefully): Use regular expressions for validation, but be extremely careful to avoid ReDoS (Regular Expression Denial of Service) vulnerabilities.