mitigations.md

Mitigation Strategies Analysis for jordansissel/fpm

Mitigation Strategy: Pin Dependencies (as used by fpm)

1. Mitigation Strategy: Pin Dependencies (as used by fpm)

   • Description:

     1. Identify Dependencies: List all direct dependencies in your project's dependency specification file (e.g., Gemfile for Ruby, requirements.txt for Python) that fpm will use.
     2. Specify Exact Versions: For each dependency, specify the exact version number. Instead of gem 'sinatra', use gem 'sinatra', '2.2.3'. Avoid version ranges or no specifier.
     3. Generate Lockfile: Use the appropriate tool (e.g., bundle install for Ruby, pip freeze > requirements.txt or pipenv/poetry for Python) to generate a lockfile.
     4. Commit Lockfile: Commit the lockfile (e.g., Gemfile.lock, requirements.txt, Pipfile.lock) to version control.
     5. Ensure fpm Uses Lockfile: fpm should automatically use the lockfile if it exists and is appropriate for the input type (e.g., -s gem will use Gemfile.lock). This ensures fpm pulls the exact versions specified, not just any matching version. There's no explicit fpm flag for this; it's inherent in how fpm handles different input types.

   • Threats Mitigated:

     • Dependency Confusion/Substitution (High Severity): fpm will not pull in a malicious package with a higher version number from a public repository if the exact version is pinned and locked.
     • Supply Chain Attacks on Dependencies (High Severity): fpm will use the known-good, locked versions of dependencies, even if a newer, compromised version is published.
     • Unintentional Breaking Changes (Medium Severity): fpm will consistently use the same dependency versions, preventing unexpected behavior.

   • Impact:

     • Dependency Confusion/Substitution: Risk significantly reduced (almost eliminated when combined with private repositories, but even without, pinning prevents fpm from grabbing the wrong version).
     • Supply Chain Attacks on Dependencies: Risk significantly reduced; fpm is locked to specific, known-good versions.
     • Unintentional Breaking Changes: Risk eliminated; fpm uses consistent versions.

   • Currently Implemented:

     • Example: Partially. Gemfile uses some version pinning, but requirements.txt uses loose versioning. Lockfiles are generated but not consistently checked.

   • Missing Implementation:

     • Example: requirements.txt needs strict version pinning. CI/CD should fail if lockfiles are out-of-date, ensuring fpm always uses the locked versions.

Mitigation Strategy: Controlled Input Source (for fpm)

2. Mitigation Strategy: Controlled Input Source (for fpm)

   • Description:

     1. Identify fpm Input: Identify all sources of input directly provided to fpm commands (e.g., directories with -s dir, files, command-line arguments).
     2. Restrict Sources: Limit these input sources to trusted locations. Ideally, this is a dedicated build directory within a CI/CD pipeline, populated only with files from your version control system.
     3. Avoid Untrusted Input: Never run fpm directly on untrusted user-supplied input (e.g., a directory uploaded by a user). If user input is indirectly involved (e.g., influencing the contents of a build directory), sanitize and validate it before it affects the input to fpm.
     4. CI/CD Integration: Use a CI/CD pipeline to automate the fpm build process. This ensures fpm receives a consistent, controlled set of inputs, pulled from version control and processed in a defined environment. The CI/CD pipeline itself becomes the "controlled source."

   • Threats Mitigated:

     • Path Traversal (High Severity): Prevents attackers from using malicious input to fpm (e.g., a crafted directory structure) to access files outside the intended build directory.
     • Arbitrary File Inclusion (High Severity): Reduces the risk of fpm including malicious files in the package if the input source is compromised.
     • Code Injection (Critical Severity): If input files to fpm contain code (e.g., scripts), this mitigates the risk of malicious code being injected through that input.

   • Impact:

     • Path Traversal: Risk significantly reduced; fpm operates within a controlled environment.
     • Arbitrary File Inclusion: Risk significantly reduced; fpm's input is restricted.
     • Code Injection: Risk significantly reduced; fpm's input comes from a trusted source (version control).

   • Currently Implemented:

     • Example: Partially. fpm is usually run in CI/CD, but manual builds exist.

   • Missing Implementation:

     • Example: Eliminate all manual fpm invocations. Ensure the CI/CD pipeline is the only way packages are built with fpm. Add input validation within the CI/CD pipeline to check for suspicious file names or content before fpm is invoked.

Mitigation Strategy: Keep fpm Updated

3. Mitigation Strategy: Keep fpm Updated

   • Description:

     1. Monitor Releases: Regularly check for new fpm releases (GitHub, RubyGems.org).
     2. Update Command: When a new version is available, update fpm. This is typically done via gem update fpm (if installed as a gem) or your system's package manager. This directly impacts fpm's behavior.
     3. Test After Update: After updating fpm, run your test suite to ensure no regressions were introduced.

   • Threats Mitigated:

     • Vulnerabilities in fpm Itself (Variable Severity): Reduces the risk of exploiting known vulnerabilities within fpm. These could allow an attacker to control the build or the resulting package.

   • Impact:

     • Vulnerabilities in fpm Itself: Risk reduced (depends on the specific vulnerabilities patched).

   • Currently Implemented:

     • Example: Partially. fpm is updated periodically, but not automatically.

   • Missing Implementation:

     • Example: Automate checking for new fpm releases and updating it in the development environment and CI/CD pipeline.

Mitigation Strategy: Minimize and Review Scripts (used by fpm)

4. Mitigation Strategy: Minimize and Review Scripts (used by fpm)

   • Description:

     1. Identify Scripts: Identify all pre/post-install/uninstall scripts that fpm will include in the generated package. These might be explicitly provided to fpm (e.g., using --before-install, --after-install flags) or implicitly generated by fpm based on the input type (e.g., from a control file in a Debian source directory).
     2. Justify Necessity: For each script, determine if it's absolutely required. Can the functionality be achieved declaratively (e.g., through package dependencies or configuration files)?
     3. Simplify: If a script is necessary, keep it as short and simple as possible. Avoid complex logic.
     4. Review for Vulnerabilities: Thoroughly review each script for:
        • Shell Injection: Ensure user input is never used directly in shell commands without proper escaping. Use parameterized commands or libraries.
        • Hardcoded Credentials: Never store credentials in scripts. Use environment variables or secure configuration.
        • Unnecessary Privileges: Scripts should run with the minimum necessary privileges. Avoid running as root unless absolutely required.
        • External Calls: Minimize/eliminate calls to external commands (e.g., curl, wget). If unavoidable, verify downloaded resource integrity (checksums).
     5. Provide to fpm securely: When providing scripts to fpm (using flags like --before-install), ensure the script files themselves come from a trusted source (version control).
     6. Automated checks: Use linters and static analysis tools to automatically check for common scripting errors and vulnerabilities.

   • Threats Mitigated:

     • Arbitrary Code Execution (Critical Severity): Reduces the risk of an attacker injecting malicious code into scripts that fpm includes in the package, which are then executed during installation.
     • Privilege Escalation (High Severity): Prevents scripts included by fpm from running with unnecessary privileges.
     • Information Disclosure (Medium Severity): Reduces the risk of sensitive information leaks through scripts included by fpm.

   • Impact:

     • Arbitrary Code Execution: Risk significantly reduced (but not eliminated, as scripts might still exist).
     • Privilege Escalation: Risk significantly reduced.
     • Information Disclosure: Risk reduced.

   • Currently Implemented:

     • Example: Partially. Some scripts exist, but they haven't been thoroughly reviewed.

   • Missing Implementation:

     • Example: Comprehensive script review is needed. Simplify scripts. Add automated checks for scripting vulnerabilities to the CI/CD pipeline before fpm is invoked.