attack-surface.md

Attack Surface Analysis for tauri-apps/tauri

Attack Surface: IPC Command Exposure (Overly Permissive allowlist)

• Description: The tauri.conf.json allowlist controls which Rust commands the frontend can invoke. Overly broad permissions grant the frontend excessive power.
  • How Tauri Contributes: Tauri's core functionality relies on this IPC mechanism. The allowlist is Tauri's primary control point.
  • Example: An allowlist entry like "fs": { "scope": ["$APP/*"] } allows the frontend to access any file within the application's data directory. If combined with a vulnerable command that doesn't validate file paths, this could lead to arbitrary file read/write. A more dangerous example is "shell": { "open": true, "scope": ["*"] }, which allows execution of any shell command.
  • Impact: Arbitrary file read/write, code execution, privilege escalation, data exfiltration.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Developer:
      • Strict Allowlist: Use the most restrictive allowlist possible. Only enable specific commands needed by the frontend. Avoid wildcards.
      • Granular Scopes: Use fine-grained scopes for each command, limiting access to specific files, directories, or resources.
      • Regular Review: Regularly review and update the allowlist as the application evolves. Remove unused commands.

Attack Surface: IPC Command Input Injection

• Description: Even with a restricted allowlist, vulnerabilities in the Rust command handlers can allow attackers to inject malicious input, leading to various attacks.
  • How Tauri Contributes: Tauri facilitates the communication, but the vulnerability lies in how the Rust backend handles the data received from the frontend.
  • Example: A command to read a file, read_user_file, takes a filename as input from the frontend. If the Rust code directly uses this filename without validation, an attacker could provide a path like "../../etc/passwd" to read system files (path traversal).
  • Impact: Arbitrary file read/write, code execution (if command injection is possible), SQL injection (if interacting with a database), data corruption.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Developer:
      • Input Validation (Rust Side): Always validate and sanitize all input received from the frontend on the Rust side. Use strong typing and parsing libraries.
      • Parameterized Queries: If interacting with a database, use parameterized queries (prepared statements) to prevent SQL injection.
      • Safe Path Handling: Use Rust's Path and PathBuf types and their methods to safely manipulate file paths. Avoid string concatenation.
      • Principle of Least Privilege: Ensure the application runs with the minimum necessary privileges.

Attack Surface: Tauri Filesystem API (fs) - Path Traversal

• Description: The fs module allows file system access. If the frontend can influence file paths, attackers can attempt path traversal to access unauthorized files.
  • How Tauri Contributes: Tauri provides the fs API, making file system interaction convenient, but also increasing the risk if misused.
  • Example: An application allows users to upload images. If the backend doesn't properly sanitize the filename provided by the frontend, an attacker could upload a file named "../../../etc/passwd" to overwrite a system file (if permissions allow).
  • Impact: Arbitrary file read/write, data corruption, potential code execution (depending on the overwritten file).
  • Risk Severity: High
  • Mitigation Strategies:
    • Developer:
      • Strict Path Validation (Rust Side): Validate and sanitize all file paths received from the frontend. Ensure they are within the expected directory and don't contain traversal sequences (..).
      • Use of Path and PathBuf: Leverage Rust's path manipulation tools to prevent common path traversal vulnerabilities.
      • Whitelist Allowed Extensions: If accepting file uploads, enforce a strict whitelist of allowed file extensions.
      • Randomize File Names: Store uploaded files with randomly generated names to prevent attackers from predicting or controlling filenames.

Attack Surface: Tauri Shell API (shell) - Command Injection

• Description: The shell API allows executing shell commands. If the frontend can influence the command or its arguments, this is a direct path to code execution.
  • How Tauri Contributes: Tauri provides the shell API, which, while powerful, is inherently dangerous if not used with extreme caution.
  • Example: An application uses the shell API to run a system utility. If the frontend can provide arguments to this utility, an attacker could inject malicious commands. For instance, if the command is ls [user_input], an attacker could provide "; rm -rf /; #" to execute arbitrary commands.
  • Impact: Arbitrary code execution, complete system compromise.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Developer:
      • Avoid shell API if Possible: Explore alternative solutions that don't require shell execution (e.g., Rust libraries).
      • Parameterized Commands: If shell is unavoidable, never construct commands using string concatenation with user input. Use parameterized commands (e.g., Command::new("program").arg("arg1").arg("arg2")).
      • Strict Input Validation: If arguments must be passed, rigorously validate and sanitize them. Use a whitelist of allowed characters and patterns.

Attack Surface: Tauri HTTP API (http) - Server-Side Request Forgery (SSRF)

• Description: If the frontend can specify URLs for the backend to fetch, attackers can exploit this to access internal resources or interact with other services.
  • How Tauri Contributes: Tauri provides the http API for making HTTP requests from the backend.
  • Example: An application allows users to enter a URL to fetch and display its content. An attacker could enter http://localhost:8080/admin or http://169.254.169.254/latest/meta-data/ (AWS metadata endpoint) to access internal services or sensitive information.
  • Impact: Access to internal network resources, data exfiltration, interaction with other services on behalf of the application.
  • Risk Severity: High
  • Mitigation Strategies:
    • Developer:
      • URL Allowlist: Implement a strict allowlist of permitted domains/URLs that the backend can access.
      • Input Validation: Validate and sanitize all URLs provided by the frontend.
      • Avoid Fetching User-Provided URLs: If possible, avoid fetching URLs directly provided by the user. If necessary, use a proxy or intermediary service to sanitize and validate the requests.
      • Network Segmentation: If possible, isolate the application from sensitive internal networks.

Attack Surface: Tauri Updater - Man-in-the-Middle (MitM)

• Description: Attackers could intercept the update process to deliver a malicious update.
  • How Tauri Contributes: Tauri provides a built-in updater mechanism.
  • Example: An attacker intercepts the network traffic between the application and the update server and replaces the legitimate update with a malicious one.
  • Impact: Installation of malicious code, complete system compromise.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Developer:
      • HTTPS: Use HTTPS for all update communication.
      • Code Signing: Digitally sign updates and verify the signature before installation.
      • Secure Update Server: Ensure the update server is secure and protected against compromise.

Attack Surface: Native Plugins - Plugin Vulnerabilities

• Description: Vulnerabilities in native plugins can lead to severe consequences, as they operate with backend privileges.
  • How Tauri Contributes: Tauri allows the integration of native plugins, extending functionality but also expanding the attack surface.
  • Example: A plugin designed to interact with a specific hardware device has a buffer overflow vulnerability. An attacker could exploit this vulnerability through the plugin's interface to execute arbitrary code.
  • Impact: Arbitrary code execution, privilege escalation, data exfiltration, system compromise.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Developer:
      • Thorough Vetting: Carefully vet any third-party plugins before integrating them.
      • Secure Coding Practices: If developing custom plugins, follow secure coding practices, including input validation, memory safety, and error handling.
      • Regular Audits: Regularly audit plugin code for vulnerabilities.
      • Sandboxing (if possible): Explore sandboxing techniques to isolate plugins and limit their access to system resources.