Create a hook that blocks dangerous bash commands

Convenience function to create a PreToolUse hook that blocks potentially dangerous bash commands. Default patterns include:

File system destruction: rm -rf, mkfs, dd if=, writes to /dev/

Privilege escalation: sudo, su -, chmod 777, chown, setuid

Code execution: eval, exec, source (with variables), backticks

Process manipulation: kill -9, killall, pkill, fork bombs

System modification: crontab, systemctl, /etc/passwd, /etc/shadow

Network exfiltration: curl -X POST, wget --post, nc -e, netcat, reverse shells

Obfuscation detection: Variable expansion in commands, base64 piping, hex/octal escapes, quote splitting, backslash escapes

Security Note: This is defense-in-depth and cannot catch all possible obfuscation techniques. For high-security environments, consider:

1. Using sandboxed execution (Docker, firejail)

2. Disabling bash entirely via Permissions

3. Using a command whitelist instead of blacklist

Usage

hook_block_dangerous_bash(patterns = NULL, additional_patterns = NULL)

Arguments

patterns

Character vector of regex patterns to block. Default includes comprehensive dangerous patterns.

additional_patterns

Optional character vector of additional patterns to block alongside defaults.

Value

A HookMatcher object

Examples

if (FALSE) { # \dontrun{
# Use default patterns
agent$add_hook(hook_block_dangerous_bash())

# Add custom patterns
agent$add_hook(hook_block_dangerous_bash(
  additional_patterns = c("my_custom_pattern", "another_pattern")
))
} # }