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attack-surface.md

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Attack Surface Analysis for skwp/dotfiles

Attack Surface: Arbitrary Command Execution on Shell Startup

  • Description: Malicious commands embedded in dotfiles are automatically executed when a new shell session starts.
  • Dotfiles Contribution: Shell configuration files within dotfiles (e.g., .bashrc, .zshrc) are sourced on shell initialization, executing any commands they contain.
  • Example: A dotfile's .bashrc includes a line that downloads and executes a backdoor script from a remote server upon opening a terminal.
  • Impact: Full system compromise, data theft, malware installation.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Rigorous Code Review: Thoroughly examine all shell configuration files in dotfiles for any commands before adoption.
    • Isolated Testing: Test dotfiles in a virtual machine before applying them to a production system.
    • Principle of Least Privilege: Avoid running dotfile installation scripts with sudo.

Attack Surface: Environment Variable Manipulation

  • Description: Dotfiles modify environment variables to alter system or application behavior in a malicious way.
  • Dotfiles Contribution: Shell configuration files in dotfiles can set or alter environment variables, potentially redirecting program execution or exposing vulnerabilities.
  • Example: A dotfile's .zshrc modifies the PATH variable to prioritize a malicious directory, allowing for command hijacking.
  • Impact: Privilege escalation, command injection, information disclosure.
  • Risk Severity: High
  • Mitigation Strategies:
    • Careful Review of PATH Changes: Pay close attention to modifications of the PATH environment variable in dotfiles.
    • Environment Isolation: Use containers or virtual environments to limit the impact of environment variable changes.
    • Regular Auditing: Monitor environment variables for unexpected changes after dotfile adoption.

Attack Surface: Alias and Function Overriding

  • Description: Dotfiles redefine standard commands with malicious aliases or functions.
  • Dotfiles Contribution: Shell configuration files within dotfiles can define aliases and functions that override built-in commands, potentially intercepting and manipulating user actions.
  • Example: A dotfile's .bashrc defines an alias for sudo that logs passwords before executing the actual sudo command.
  • Impact: Credential theft, unauthorized command execution, privilege escalation.
  • Risk Severity: High
  • Mitigation Strategies:
    • Inspect Alias and Function Definitions: Carefully review all alias and function definitions in dotfiles, especially for security-sensitive commands.
    • Command Verification: Use which or type to verify the actual command being executed, especially after adopting dotfiles.
    • Disable Suspicious Aliases: Temporarily disable suspicious aliases using unalias for testing or critical operations.

Attack Surface: Malicious Scripts Included in Dotfiles

  • Description: Dotfiles repositories contain intentionally malicious scripts disguised as utilities.
  • Dotfiles Contribution: Dotfiles repositories may include custom scripts for convenience. Malicious dotfiles can include scripts designed to compromise the system when executed.
  • Example: A dotfile repository includes a script named system_cleanup.sh that, when executed, installs a backdoor instead of performing cleanup.
  • Impact: Full system compromise, data theft, malware installation.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Thorough Script Review: Meticulously examine every script within dotfiles before execution.
    • Static Analysis of Scripts: Use static analysis tools to scan scripts for malicious patterns.
    • Sandboxed Script Execution: Execute scripts in a virtual machine or isolated environment for initial assessment.

Attack Surface: Vulnerable Scripts Included in Dotfiles

  • Description: Well-intentioned scripts within dotfiles contain exploitable coding vulnerabilities.
  • Dotfiles Contribution: Scripts included in dotfiles, even if not malicious in intent, may contain vulnerabilities like command injection or path traversal due to poor coding practices.
  • Example: A script in dotfiles that processes filenames without proper sanitization is vulnerable to command injection if a user provides a malicious filename.
  • Impact: Privilege escalation, command injection, data manipulation.
  • Risk Severity: High
  • Mitigation Strategies:
    • Code Review for Vulnerabilities: Review scripts for common coding vulnerabilities like command injection and path traversal.
    • Input Sanitization in Scripts: Ensure scripts properly sanitize user inputs to prevent injection attacks.
    • Secure Coding Practices: Follow secure coding practices when writing or reviewing scripts in dotfiles.

Attack Surface: Compromised External Scripts or Resources (Supply Chain)

  • Description: Dotfiles download external scripts or resources from compromised sources during installation or runtime.
  • Dotfiles Contribution: Dotfile installation scripts or configuration files might fetch scripts or other resources from external URLs. If these external sources are compromised, malicious resources can be introduced.
  • Example: A dotfile installation script downloads a bootstrap script from a compromised domain, leading to malware installation during dotfile setup.
  • Impact: Full system compromise, malware installation.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Verify External Source Trustworthiness: Thoroughly verify the trustworthiness and integrity of external sources before downloading resources.
    • HTTPS and Checksum Verification: Use HTTPS for downloads and verify checksums of downloaded resources when possible.
    • Minimize External Dependencies: Reduce reliance on external scripts and resources in dotfiles to minimize supply chain risks.