attack-surface.md

Attack Surface Analysis for swc-project/swc

Attack Surface: 1. Malicious Code Input (Parsing/Transformation)

• Description: Attackers provide crafted JavaScript/TypeScript code designed to exploit vulnerabilities in swc's parsing or transformation logic.
• swc Contribution: swc is the primary component responsible for parsing and processing the potentially malicious input code. Its internal logic and algorithms are the direct target.
• Example: An attacker submits deeply nested object literals with specially crafted property names designed to trigger a stack overflow or excessive memory allocation during parsing. Another example is a regular expression designed to cause catastrophic backtracking.
• Impact:
  • Denial of Service (DoS): Crashing the swc process or consuming excessive resources.
  • Arbitrary Code Execution (ACE): In the worst case, a buffer overflow or similar vulnerability could allow the attacker to execute arbitrary code within the context of the process running swc.
  • Information Disclosure: In some cases, carefully crafted input could lead to leaking of internal swc state or memory contents.
• Risk Severity: Critical (for ACE potential) / High (for DoS)
• Mitigation Strategies:
  • Fuzz Testing: Implement continuous fuzz testing using tools like cargo fuzz (for Rust) or JavaScript fuzzers adapted to target swc's API. Provide a wide variety of valid, invalid, and edge-case inputs.
  • Resource Limits: Enforce strict limits on CPU time, memory allocation, and input size when invoking swc. Use operating system-level mechanisms (e.g., ulimit on Linux, process groups) or language-specific features (e.g., Node.js resource limits).
  • Input Size Limits: Reject excessively large or complex input files before they are processed by swc. This is a defense-in-depth measure.
  • Regular Updates: Keep swc updated to the latest version to benefit from security patches and improvements. Subscribe to security advisories for swc.
  • Panic Handling (Rust-Specific): Ensure that swc handles errors gracefully and avoids panicking on unexpected input. Use Rust's Result type to propagate errors and handle them appropriately.
  • WASM Sandboxing (If Applicable): If using swc in a WASM environment, leverage the inherent sandboxing capabilities of WASM to limit the impact of potential vulnerabilities.

Attack Surface: 2. Malicious swc Plugins

• Description: Attackers provide or convince the application to use a malicious swc plugin.
• swc Contribution: swc's plugin architecture allows for extending its functionality, but this also introduces a significant attack surface if plugins are not carefully vetted.
• Example: An attacker publishes a seemingly benign swc plugin that, in reality, contains code to exfiltrate environment variables or modify the output of the compilation process to inject malicious JavaScript.
• Impact:
  • Arbitrary Code Execution (ACE): The malicious plugin can execute arbitrary code with the privileges of the process running swc.
  • Data Exfiltration: The plugin could steal sensitive data processed by swc or accessible to the process.
  • Code Modification: The plugin could alter the output of swc, potentially introducing vulnerabilities into the final application.
• Risk Severity: Critical
• Mitigation Strategies:
  • Avoid Untrusted Plugins: Never use swc plugins from untrusted sources. This is the most important mitigation.
  • Plugin Source Code Review: If using a third-party plugin, thoroughly review its source code for any suspicious behavior or potential vulnerabilities. Look for network access, file system access, or attempts to modify the compilation process in unexpected ways.
  • Plugin Signing (Ideal): Ideally, swc would support a plugin signing mechanism to verify the authenticity and integrity of plugins. This is a feature request for the swc project.
  • Sandboxing (Difficult but Ideal): Explore options for running swc plugins in a sandboxed environment (e.g., a separate process with limited privileges, a WASM environment). This is a complex undertaking but provides strong isolation.
  • Minimize Plugin Usage: Use as few plugins as absolutely necessary to reduce the attack surface.
  • Regular Plugin Updates: If you must use a plugin, keep it updated to the latest version.

Attack Surface: 3. Malicious Configuration (.swcrc or API Options)

• Description: Attackers manipulate the swc configuration to enable dangerous features or disable security protections.
• swc Contribution: swc relies on configuration files (e.g., .swcrc) or API options to control its behavior. Incorrect or malicious configurations can weaken security.
• Example: An attacker modifies the .swcrc file to disable source map generation (which might seem harmless) but then uses this to obfuscate a separate attack. Or, they might enable an experimental feature that is known to be unstable or have security issues. Another example is configuring a malicious plugin to be loaded.
• Impact:
  • Reduced Security: Disabling security features or enabling unsafe options can make the application more vulnerable.
  • Indirect Attacks: Malicious configurations can be used to facilitate other attacks, such as making it harder to detect injected code.
  • Plugin Loading: Loading malicious plugins via configuration.
• Risk Severity: High
• Mitigation Strategies:
  • Configuration Validation: Validate the swc configuration against a strict schema. Reject any unknown or unexpected options. Use a JSON schema validator or a similar tool.
  • Secure Configuration Storage: Store configuration files securely and prevent unauthorized modifications. Use file system permissions and access controls.
  • Principle of Least Privilege: Only enable the swc features and options that are absolutely necessary. Avoid overly permissive configurations.
  • Avoid User-Supplied Configuration: Never allow users to directly upload or modify swc configuration files. Treat configuration as trusted code.
  • Hardcode Safe Defaults: If possible, hardcode safe default values for swc options within the application code, rather than relying solely on external configuration files.

Attack Surface: 4. Vulnerabilities in swc Dependencies

• Description: swc depends on other libraries (Rust crates). Vulnerabilities in these dependencies can be exploited.
• swc Contribution: swc indirectly introduces these vulnerabilities by relying on the dependencies.
• Example: A vulnerability is discovered in a Rust crate used by swc for parsing regular expressions. An attacker could exploit this vulnerability by providing a specially crafted regular expression to swc.
• Impact: Varies depending on the specific vulnerability in the dependency. Could range from DoS to ACE.
• Risk Severity: High (Potentially Critical, depending on the dependency)
• Mitigation Strategies:
  • Dependency Auditing: Regularly audit swc's dependencies for known vulnerabilities. Use tools like cargo audit (for Rust) or npm audit (if using swc through its JavaScript API).
  • Dependency Updates: Keep dependencies updated to their latest versions. Use a dependency management tool (e.g., Cargo.lock for Rust, package-lock.json or yarn.lock for JavaScript) to ensure consistent and reproducible builds.
  • Vulnerability Monitoring: Subscribe to security advisories for swc and its dependencies.