threat-modeling.md

Threat Model Analysis for burntsushi/ripgrep

Threat: Command Injection via --pre option

• Description: An attacker provides malicious input that is directly incorporated into the --pre option of the ripgrep command as executed by the application. ripgrep then executes this attacker-controlled command as a preprocessor on files before searching them. This is a direct exploitation of ripgrep's intended functionality, but in a malicious way due to improper input handling by the calling application.
• Impact: Complete system compromise. The attacker gains the ability to execute arbitrary commands with the privileges of the user running the ripgrep process. This could lead to data theft, data modification, system takeover, and lateral movement.
• Ripgrep Component Affected: ripgrep's internal command-line argument parsing and the execution logic for the --pre option, specifically the code that spawns the preprocessor subprocess.
• Risk Severity: Critical
• Mitigation Strategies:
  • Disable --pre: The most secure option is to completely disallow the use of the --pre option within the application.
  • Strict Whitelisting (if --pre is essential): Implement a very strict whitelist of allowed preprocessor commands. Never allow the user to directly specify the command.
  • Input Sanitization (secondary defense): Sanitize any user input passed as arguments to the whitelisted preprocessor. Use a library for safe command-line argument construction.
  • Least Privilege: Run ripgrep (and the preprocessor) with the lowest possible privileges.
  • Sandboxing/Containerization: Run ripgrep (and the preprocessor) within a container or sandbox.

Threat: Command Injection via --search-zip option (Indirect, Exploiting Decompression Utility)

• Description: An attacker provides a malicious path to a crafted "zip" file. When ripgrep is invoked with the --search-zip option, it uses an external decompression utility. The attacker exploits a vulnerability in that external utility, triggered by the malicious archive. This is indirect command injection; ripgrep is the vector, but the vulnerability is in another program.
• Impact: Potentially high, depending on the vulnerability in the decompression utility. Could range from denial of service to arbitrary code execution.
• Ripgrep Component Affected: ripgrep's code that handles the --search-zip option and invokes the external decompression utility. The vulnerability itself is not in ripgrep.
• Risk Severity: High
• Mitigation Strategies:
  • Disable --search-zip: If searching within compressed archives is not essential, disable this option.
  • Controlled Input: If --search-zip is needed, strictly control the paths that ripgrep can access. Do not allow arbitrary file paths from users.
  • Sandboxing/Containerization: Isolate the ripgrep process (and the decompression utility).
  • Keep Decompression Utilities Updated: Ensure that the system's decompression utilities are up-to-date with security patches.
  • Input Validation (Limited): Validate the path to ensure it's within the allowed directory and has a whitelisted extension.

Threat: Denial of Service via Catastrophic Backtracking Regex

• Description: An attacker provides a regular expression that, when processed by ripgrep's regex engine (either PCRE2 or Rust's regex crate), causes excessive CPU and memory consumption due to catastrophic backtracking. This is a direct attack on ripgrep's regex processing capabilities.
• Impact: Denial of Service. ripgrep becomes unresponsive, consuming excessive resources and preventing legitimate searches.
• Ripgrep Component Affected: The regex engine used by ripgrep (PCRE2 or Rust's regex crate).
• Risk Severity: High
• Mitigation Strategies:
  • Regex Complexity Limits: Use a regex engine with built-in protections against catastrophic backtracking (Rust's regex crate has some). Consider using a regex complexity analyzer/limiter.
  • Input Length Limits: Impose a reasonable limit on the length of user-provided regular expressions.
  • Timeouts: Implement timeouts for ripgrep processes. Terminate searches that take too long.
  • Resource Quotas: Use OS features or containerization to limit CPU and memory for the ripgrep process.