threat-modeling.md

Threat Model Analysis for skwp/dotfiles

Threat: Compromised Upstream Repository

Description: An attacker compromises the source code repository (e.g., GitHub) where dotfiles are hosted. They inject malicious code into dotfiles, such as shell scripts or configuration files. This could be achieved through account compromise, exploiting repository vulnerabilities, or insider threats.

• Impact: Critical. If the application fetches and applies dotfiles from the compromised repository, it will execute malicious code. This can lead to full system compromise, data breaches, denial of service, and reputational damage.
• Affected Dotfiles Component: Entire dotfiles repository, specifically any script files (e.g., .bashrc, .zshrc, custom scripts), configuration files, and potentially even seemingly benign files if they are processed by scripts.
• Risk Severity: Critical
• Mitigation Strategies:
  • Vet Repository Source: Thoroughly vet the dotfiles repository and its maintainers before using it. Choose repositories with a strong security track record and active community.
  • Repository Integrity Checks: Implement mechanisms to verify the integrity of the downloaded dotfiles, such as using checksums or digital signatures provided by the repository maintainers.
  • Regular Audits of Upstream: Periodically audit the upstream repository for any suspicious changes or commits.
  • Fork and Control: Consider forking the repository and hosting it under your own control to have greater oversight and reduce reliance on external sources.
  • Dependency Pinning/Versioning: If possible, use specific versions or commits of the dotfiles repository to avoid automatically pulling in potentially compromised updates.

Threat: Man-in-the-Middle (MITM) Attack during Download/Update

Description: An attacker intercepts the network traffic when the application downloads or updates dotfiles from a remote server. They replace the legitimate dotfiles with malicious ones before they reach the application. This is possible if the download occurs over an insecure channel like plain HTTP.

• Impact: High. Similar to a compromised repository, malicious dotfiles delivered via MITM can lead to arbitrary code execution, system compromise, and data breaches.
• Affected Dotfiles Component: Download mechanism, specifically the communication channel used to retrieve dotfiles.
• Risk Severity: High
• Mitigation Strategies:
  • HTTPS for Downloads: Always use HTTPS to download dotfiles to ensure encrypted communication and prevent MITM attacks.
  • Integrity Verification: Implement integrity checks (checksums, signatures) for downloaded dotfiles to detect if they have been tampered with during transit.
  • Secure Download Infrastructure: Ensure the server hosting the dotfiles is securely configured and protected against compromise.

Threat: Arbitrary Code Execution via Shell Scripts in Dotfiles

Description: Dotfiles contain shell scripts (e.g., in .bashrc, .zshrc, custom scripts). An attacker injects malicious shell commands into these scripts. When the application sources or executes these dotfiles, the malicious commands are executed with the application's privileges.

• Impact: Critical. Shell scripts can execute arbitrary commands on the system. This can lead to full system compromise, privilege escalation, data exfiltration, denial of service, and installation of backdoors.
• Affected Dotfiles Component: Shell scripts within dotfiles (e.g., .bashrc, .zshrc, custom scripts).
• Risk Severity: Critical
• Mitigation Strategies:
  • Code Review and Static Analysis: Thoroughly review all shell scripts in dotfiles for suspicious or malicious code patterns before deployment. Use static analysis tools to automatically detect potential vulnerabilities.
  • Sandboxing and Isolation: Execute dotfile scripts in a sandboxed environment with restricted privileges and limited access to system resources. Consider using containers or virtual machines.
  • Principle of Least Privilege: Run the application and dotfile execution processes with the minimum necessary privileges to limit the impact of successful exploitation.
  • Input Validation and Sanitization: If dotfiles scripts take user input, rigorously validate and sanitize this input to prevent command injection vulnerabilities.
  • Disable Unnecessary Features: Disable or remove any unnecessary or overly complex shell scripts from dotfiles to reduce the attack surface.

Threat: Alias and Function Hijacking

Description: An attacker injects malicious aliases or functions into dotfiles that redefine standard commands (e.g., ls, sudo, git). When a user or the application uses these commands, the malicious alias or function is executed instead, potentially performing unintended and harmful actions.

• Impact: High. Can lead to subtle data manipulation, information disclosure, or further exploitation. It can be harder to detect than outright malicious scripts.
• Affected Dotfiles Component: Aliases and function definitions within dotfiles (e.g., .bashrc, .zshrc).
• Risk Severity: High
• Mitigation Strategies:
  • Code Review: Carefully review dotfiles for any unusual or suspicious alias and function definitions.
  • Command Whitelisting: If possible, restrict the commands that the application or user environment can execute to a predefined whitelist, preventing the execution of hijacked commands.
  • Disable Alias/Function Expansion (where applicable): In certain contexts, it might be possible to disable alias and function expansion to ensure commands are executed as intended.
  • Regular Monitoring: Monitor system logs and user activity for any signs of unexpected command execution or behavior that might indicate alias/function hijacking.

Threat: Configuration File Manipulation (Application-Specific Dotfiles)

Description: An attacker modifies application-specific configuration files within dotfiles. This can involve changing security settings, disabling security features, or exposing sensitive data stored in configuration files.

• Impact: High. Impact depends on the application and the configuration settings modified. Can lead to application-specific vulnerabilities, data breaches, denial of service, or bypass of security controls.
• Affected Dotfiles Component: Application-specific configuration files within dotfiles (e.g., .gitconfig, .vimrc, application configuration files).
• Risk Severity: High
• Mitigation Strategies:
  • Configuration File Schema Validation: Define and enforce a strict schema for application configuration files to prevent malicious or invalid configurations.
  • Secure Configuration Defaults: Use secure default configurations for the application and minimize reliance on user-configurable settings from dotfiles for critical security parameters.
  • Configuration File Integrity Checks: Implement integrity checks (checksums, signatures) for configuration files to detect unauthorized modifications.
  • Principle of Least Privilege for Configuration Access: Restrict access to configuration files to only necessary processes and users.

Threat: Unintended Execution of Dotfiles

Description: The application unintentionally sources or executes dotfiles from untrusted locations or in unintended contexts. For example, processing user-uploaded files might inadvertently trigger the execution of dotfiles contained within the archive.

• Impact: High. Accidental execution of malicious code from dotfiles can lead to system compromise, especially if the dotfiles are from an untrusted source.
• Affected Dotfiles Component: Dotfile execution mechanism, specifically the logic that triggers dotfile sourcing or execution.
• Risk Severity: High
• Mitigation Strategies:
  • Strict Control over Dotfile Execution: Carefully control when and where dotfiles are sourced or executed. Avoid automatic or implicit execution of dotfiles from untrusted sources.
  • Explicit Dotfile Loading: Implement explicit mechanisms for loading dotfiles from trusted locations only, rather than relying on implicit or automatic discovery.
  • Input Sanitization for File Paths: If file paths are used to locate dotfiles, sanitize and validate these paths to prevent path traversal attacks or unintended file access.

Threat: Insufficient Sandboxing or Isolation

Description: The application executes dotfiles without proper sandboxing or isolation. Malicious code within dotfiles can then affect the host system or other parts of the application, potentially escalating the impact of a compromise.

• Impact: High. Lack of sandboxing increases the blast radius of a successful dotfile-based attack, potentially leading to wider system compromise and cross-component contamination.
• Affected Dotfiles Component: Dotfile execution environment and isolation mechanisms (or lack thereof).
• Risk Severity: High
• Mitigation Strategies:
  • Sandboxing and Containerization: Execute dotfile scripts within a sandboxed environment or container with restricted privileges and resource access.
  • Virtualization: Use virtualization technologies to isolate the application and its dotfile execution environment from the host system.
  • Process Isolation: Implement process isolation techniques to limit the impact of a compromise within the application's processes.

Threat: Permissions Issues and Privilege Escalation

Description: Incorrect file permissions on dotfiles or the directories containing them allow unauthorized modification or execution. An attacker could modify dotfiles to inject malicious code or exploit permission vulnerabilities to escalate privileges.

• Impact: High. Can lead to unauthorized access, privilege escalation, and system compromise, depending on the permission vulnerabilities and the attacker's actions.
• Affected Dotfiles Component: File system permissions on dotfiles and related directories.
• Risk Severity: High
• Mitigation Strategies:
  • Principle of Least Privilege for File Permissions: Set file permissions on dotfiles and directories to the minimum necessary for the application to function correctly. Ensure dotfiles are not world-writable.
  • Regular Permission Audits: Periodically audit file permissions to identify and correct any misconfigurations.
  • Secure File System Configuration: Harden the file system configuration to prevent unauthorized access and modification.

Threat: Data Corruption or Manipulation

Description: Malicious dotfiles contain scripts or configurations that directly manipulate application data or system files. This can lead to data corruption, unauthorized modification, or data loss.

• Impact: High. Data integrity compromise, application malfunction, and potential financial or reputational damage due to data loss or corruption.
• Affected Dotfiles Component: Any component within dotfiles that can interact with and modify data or system files (scripts, configurations, etc.).
• Risk Severity: High
• Mitigation Strategies:
  • Data Integrity Checks: Implement data integrity checks (checksums, hashing, database constraints) to detect and prevent data corruption.
  • Access Control and Authorization: Implement strict access control and authorization mechanisms to limit which processes and users can modify application data and system files.
  • Regular Backups: Implement regular data backups to recover from data corruption or loss incidents.
  • Immutable Infrastructure: Consider using immutable infrastructure principles to minimize the risk of unauthorized data modification.