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Threat Model Analysis for leoafarias/fvm

Threat: Malicious Flutter SDK Substitution (via FVM)

  • Description: An attacker crafts a malicious Flutter SDK that mimics a legitimate version. They then trick fvm into downloading and using this malicious SDK. While this relies on compromising external resources (Flutter distribution), fvm is the direct tool used to introduce the malicious SDK. The attacker might achieve this through a compromised mirror, DNS spoofing targeting the download URLs used by fvm, or a man-in-the-middle attack on the connection between fvm and the Flutter servers.
    • Impact: The attacker's malicious code is incorporated into the built application, potentially leading to data breaches, remote code execution on user devices, or other malicious behavior. The application's integrity and user trust are compromised.
    • Affected FVM Component: fvm's download and installation mechanism (specifically, the functions responsible for fetching SDKs from remote sources, like the fetch command and related internal functions). The cache directory (~/.fvm/versions) is where the malicious SDK would be stored.
    • Risk Severity: Critical
    • Mitigation Strategies:
      • Strongly Enforce HTTPS: Ensure fvm always uses HTTPS for downloading SDKs. This is generally the default, but verify configuration.
      • Implement Checksum Verification (Future Enhancement for FVM): fvm should verify the checksum of downloaded SDKs against a trusted source after download. This is a crucial feature request for fvm.
      • Use a Trusted Network: Avoid using public Wi-Fi or untrusted networks when downloading SDKs.
      • Validate Flutter SDK integrity manually (if highly concerned): Download the official Flutter SDK separately and compare its checksum with the one downloaded by fvm.

Threat: Post-Download SDK Tampering (within FVM Cache)

  • Description: After fvm downloads a legitimate Flutter SDK, an attacker with local access (e.g., compromised developer machine, malicious insider, compromised CI/CD agent) modifies the files within the fvm cache directory (~/.fvm/versions). This directly targets fvm's storage of the SDK.
    • Impact: The attacker's code is incorporated into the built application, leading to compromised application integrity and potential harm to users.
    • Affected FVM Component: The fvm cache directory (~/.fvm/versions) and any fvm commands that use the cached SDKs (e.g., fvm use, fvm flutter).
    • Risk Severity: High
    • Mitigation Strategies:
      • Restrict Cache Directory Permissions: Ensure that only authorized users and processes have write access to the ~/.fvm/versions directory. Use the principle of least privilege.
      • File Integrity Monitoring (FIM): Implement FIM on the ~/.fvm/versions directory.
      • Read-Only Cache (Ideal): If feasible, make the ~/.fvm/versions directory read-only after the initial SDK download.

Threat: FVM Configuration File Tampering

  • Description: An attacker modifies the fvm configuration files (e.g., .fvm/fvm_config.json, per-project .fvmrc files) to point to a malicious Flutter SDK version or a compromised repository. This is a direct attack on fvm's configuration.
    • Impact: The build process uses a malicious or outdated SDK, leading to compromised application integrity and potential vulnerabilities.
    • Affected FVM Component: The fvm configuration loading mechanism and any commands that rely on the configuration (e.g., fvm use, fvm flutter).
    • Risk Severity: High
    • Mitigation Strategies:
      • Version Control: Store all fvm configuration files in a version control system (e.g., Git).
      • Code Reviews: Enforce mandatory code reviews for any changes to fvm configuration files.
      • Restrict File Permissions: Limit write access to these configuration files.
      • CI/CD Validation: Have the CI/CD pipeline validate the configuration files.
      • Signed Configuration (Future Enhancement): Ideally, fvm could support digitally signed configuration files.

Threat: FVM Executable Tampering

  • Description: An attacker replaces or modifies the fvm executable itself with a malicious version. This is a direct attack on the fvm tool.
    • Impact: The attacker gains complete control over the fvm process, allowing them to manipulate SDK downloads, configurations, and potentially execute arbitrary code.
    • Affected FVM Component: The fvm executable itself.
    • Risk Severity: High
    • Mitigation Strategies:
      • Trusted Installation Source: Install fvm only from the official repository using a trusted package manager.
      • File Integrity Monitoring (FIM): Monitor the fvm executable for changes.
      • Regular Updates: Keep fvm updated.
      • Code Signing Verification (If Available): Verify the signature before running (if fvm releases are signed).

Threat: Compromised FVM repository

  • Description: Official FVM repository is compromised and attacker is publishing malicious version of FVM.
    • Impact: The attacker gains control over the system where fvm is running, potentially compromising the entire development environment or CI/CD pipeline.
    • Affected FVM Component: The fvm executable itself.
    • Risk Severity: Critical
    • Mitigation Strategies:
      • Monitor FVM repository: Monitor FVM repository for any suspicious activity.
      • Use alternative installation method: If possible, use alternative installation method, e.g. build from source.
      • Wait for official fix: Wait for official fix and announcement from FVM maintainers.

Threat: FVM Vulnerability Exploitation (Hypothetical)

  • Description: A vulnerability is discovered in fvm itself (e.g., command injection, path traversal) that allows arbitrary code execution. This is a direct threat to fvm.
    • Impact: Attacker gains control over the system where fvm is running.
    • Affected FVM Component: The specific vulnerable component within fvm.
    • Risk Severity: Critical (if a vulnerability exists)
    • Mitigation Strategies:
      • Keep FVM Updated: Regularly update fvm.
      • Run with Least Privilege: Avoid running fvm with root privileges.
      • Sandboxing (Containerization): Run fvm in a container.
      • Security Audits (for FVM Maintainers): Regularly audit the fvm codebase.