feat(security): add detection rules for destructive shell commands

src/copaw/security/tool_guard/rules/dangerous_shell_commands.yaml

@@ -27,3 +27,105 @@
     - "\\bmv\\b"
   description: "Shell command contains 'mv' which may move or overwrite files unexpectedly"
   remediation: "Confirm with the user before moving or renaming files"
+
+# ── Filesystem & Block Device Destruction ─────────────────────────────
+- id: TOOL_CMD_FS_DESTRUCTION
+  tools: [execute_shell_command]
+  params: [command]
+  category: command_injection
+  severity: CRITICAL
+  patterns:
+    - "\\bmkfs\\b"
+    - "\\bdd\\s+.*of=\\/dev\\/"
+    - ">\\s*\\/dev\\/(sda|nvme|vd)"
+  description: "Detects low-level disk formatting or wiping commands"
+  remediation: "Block operation. Agents should not format or overwrite raw block devices."
+
+# ── Git Data Loss ─────────────────────────────────────────────────────
+- id: TOOL_CMD_GIT_DATA_LOSS
+  tools: [execute_shell_command]
+  params: [command]
+  category: command_injection
+  severity: HIGH
+  patterns:
+    - "\\bgit\\s+reset\\s+(--hard|-h\\b)"
+    - "\\bgit\\s+checkout\\s+(--\\s+\\.|\\.)"
+    - "\\bgit\\s+clean\\s+-[a-zA-Z]*f"
+    - "\\bgit\\s+push\\s+.*(--force|-f\\b)"
+    - "\\bgit\\s+stash\\s+(drop|clear)"
+  description: "Detects destructive Git operations that discard uncommitted work or rewrite remote history"
+  remediation: "Suggest using 'git stash' instead of reset/checkout, or 'git push --force-with-lease'."
+
+# ── Denial of Service & Fork Bombs ────────────────────────────────────
+- id: TOOL_CMD_DOS_FORK_BOMB
+  tools: [execute_shell_command]
+  params: [command]
+  category: resource_abuse
+  severity: CRITICAL
+  patterns:
+    - ":\\(\\)\\{\\s*:\\|:&\\s*\\};:"
+    - "\\bkill\\s+-9\\s+(-1|1\\b)"
+  description: "Detects classic Bash fork bombs and mass process termination"
+  remediation: "Block immediately. These commands will crash the host system."
+
+# ── Network Loaders (Pipe to Shell) ───────────────────────────────────
+- id: TOOL_CMD_PIPE_TO_SHELL
+  tools: [execute_shell_command]
+  params: [command]
+  category: code_execution
+  severity: CRITICAL
+  patterns:
+    - "(curl|wget)\\s+.*\\|\\s*(bash|sh|zsh|ash|dash)"
+  description: "Detects 'curl | bash' patterns used to download and immediately execute remote payloads"
+  remediation: "Confirm with user. Agents should inspect scripts before executing them."
+
+# ── Reverse Shell & Network Tunnels ───────────────────────────────────
+- id: TOOL_CMD_REVERSE_SHELL
+  tools: [execute_shell_command]
+  params: [command]
+  category: network_abuse
+  severity: CRITICAL
+  patterns:
+    - "\\/dev\\/(tcp|udp)\\/"
+    - "\\bnc\\s+.*-e\\s+"
+    - "\\bncat\\s+.*-e\\s+"
+    - "\\bsocat\\s+.*EXEC:"
+  description: "Detects attempts to establish reverse shells or unauthorized network tunnels"
+  remediation: "Block operation. Agents do not need to bind interactive shells to network sockets."
+
+# ── Persistence & Privilege Escalation ────────────────────────────────
+- id: TOOL_CMD_SYSTEM_TAMPERING
+  tools: [execute_shell_command]
+  params: [command]
+  category: sensitive_file_access
+  severity: HIGH
+  patterns:
+    - "\\bcrontab\\b"
+    - "authorized_keys"
+    - "\\/etc\\/sudoers"
+    - "\\/etc\\/crontab"
+  description: "Detects access to cron jobs, SSH keys, or sudo permissions (including reads and modifications)"
+  remediation: "Confirm with user. Treat any access to credential and scheduling files as sensitive and restrict when possible."
+
+# ── Dangerous Permission Changes ──────────────────────────────────────
+- id: TOOL_CMD_UNSAFE_PERMISSIONS
+  tools: [execute_shell_command]
+  params: [command]
+  category: privilege_escalation
+  severity: HIGH
+  patterns:
+    - "\\bchmod\\s+-[a-zA-Z]*R[a-zA-Z]*\\s+(777|a\\+rwx)\\s+\\/"
+    - "\\bchattr\\s+\\+i"
+  description: "Detects global permission downgrades (chmod 777) or setting immutable flags"
+  remediation: "Prompt for confirmation. Suggest least-privilege permission models."
+
+# ── Obfuscation & Defense Evasion ─────────────────────────────────────
+- id: TOOL_CMD_OBFUSCATED_EXEC
+  tools: [execute_shell_command]
+  params: [command]
+  category: code_execution
+  severity: HIGH
+  patterns:
+    - "\\bbase64\\s+(-d|--decode)\\s*\\|\\s*(bash|sh|zsh)"
+  description: "Detects execution of base64 encoded strings passed directly to a shell interpreter"
+  remediation: "Block execution. Agents should use plain text commands."