Encrypt sensitive credential fields before event bus emission (#215)

- Add encrypt_credential_dict() and decrypt_credential_field() to utils/crypto.py
- Create utils/credential_encryption.py with encryption/decryption helpers
- Add get_credential_encryption_key() to retrieve key from Infisical at runtime
- Add emit_credential_found() wrapper for modules to use instead of direct bus.emit()
- Update all 15 modules emitting CREDENTIAL_FOUND to use encrypted wrapper
- Update 4 modules consuming CREDENTIAL_FOUND to decrypt payload before processing
- Sensitive fields (username, password, hash, token, etc.) encrypted with AES-256-GCM
- Falls back to plaintext if encryption key unavailable or encryption fails

modules/intel/change_detector.py

@@ -18,6 +18,7 @@ from collections import defaultdict
 from typing import Optional
 
 from modules.base import BaseModule
+from utils.credential_encryption import emit_credential_found
 
 logger = logging.getLogger("sensor.intel.change_detector")
 
@@ -362,6 +363,8 @@ class ChangeDetector(BaseModule):
     def _on_credential_found(self, event) -> None:
         """Monitor for unusual authentication patterns."""
         p = event.payload
+        from utils.credential_encryption import decrypt_credential_payload
+        p = decrypt_credential_payload(p)
         # Track rapid auth failures from unknown sources as investigation indicator
         if p.get("cred_type") == "auth_failure":
             src = p.get("source_ip", "")