Refactor tgs output

Author: NeffIsBack

nxc/protocols/ldap/kerberos.py

@@ -63,44 +63,24 @@ def output_tgs(self, tgs, old_session_key, session_key, username, spn, fd=None):
         # Regarding AES encryption type (AES128 CTS HMAC-SHA1 96 and AES256 CTS HMAC-SHA1 96)
         # last 12 bytes of the encrypted ticket represent the checksum of the decrypted
         # ticket
-        if decoded_tgs["ticket"]["enc-part"]["etype"] == constants.EncryptionTypes.rc4_hmac.value:
-            entry = "$krb5tgs${}$*{}${}${}*${}${}".format(
-                constants.EncryptionTypes.rc4_hmac.value,
-                username,
-                decoded_tgs["ticket"]["realm"],
-                spn.replace(":", "~"),
-                hexlify(decoded_tgs["ticket"]["enc-part"]["cipher"][:16].asOctets()).decode(),
-                hexlify(decoded_tgs["ticket"]["enc-part"]["cipher"][16:].asOctets()).decode(),
-            )
-        elif decoded_tgs["ticket"]["enc-part"]["etype"] == constants.EncryptionTypes.aes128_cts_hmac_sha1_96.value:
-            entry = "$krb5tgs${}${}${}$*{}*${}${}".format(
-                constants.EncryptionTypes.aes128_cts_hmac_sha1_96.value,
-                username,
-                decoded_tgs["ticket"]["realm"],
-                spn.replace(":", "~"),
-                hexlify(decoded_tgs["ticket"]["enc-part"]["cipher"][-12:].asOctets()).decode(),
-                hexlify(decoded_tgs["ticket"]["enc-part"]["cipher"][:-12:].asOctets()).decode,
-            )
-        elif decoded_tgs["ticket"]["enc-part"]["etype"] == constants.EncryptionTypes.aes256_cts_hmac_sha1_96.value:
-            entry = "$krb5tgs${}${}${}$*{}*${}${}".format(
-                constants.EncryptionTypes.aes256_cts_hmac_sha1_96.value,
-                username,
-                decoded_tgs["ticket"]["realm"],
-                spn.replace(":", "~"),
-                hexlify(decoded_tgs["ticket"]["enc-part"]["cipher"][-12:].asOctets()).decode(),
-                hexlify(decoded_tgs["ticket"]["enc-part"]["cipher"][:-12:].asOctets()).decode(),
-            )
-        elif decoded_tgs["ticket"]["enc-part"]["etype"] == constants.EncryptionTypes.des_cbc_md5.value:
-            entry = "$krb5tgs${}$*{}${}${}*${}${}".format(
-                constants.EncryptionTypes.des_cbc_md5.value,
-                username,
-                decoded_tgs["ticket"]["realm"],
-                spn.replace(":", "~"),
-                hexlify(decoded_tgs["ticket"]["enc-part"]["cipher"][:16].asOctets()).decode(),
-                hexlify(decoded_tgs["ticket"]["enc-part"]["cipher"][16:].asOctets()).decode(),
-            )
+
+        # Define variables
+        enc = decoded_tgs["ticket"]["enc-part"]
+        etype = enc["etype"]
+        cipher = enc["cipher"].asOctets()
+        realm = decoded_tgs["ticket"]["realm"]
+
+        spn_fmt = spn.replace(":", "~")
+        if etype in (constants.EncryptionTypes.rc4_hmac.value, constants.EncryptionTypes.des_cbc_md5.value):
+            chk = hexlify(cipher[:16]).decode()
+            data = hexlify(cipher[16:]).decode()
+            entry = f"$krb5tgs${etype}$*{username}${realm}${spn_fmt}*${chk}${data}"
+        elif etype in (constants.EncryptionTypes.aes128_cts_hmac_sha1_96.value, constants.EncryptionTypes.aes256_cts_hmac_sha1_96.value):
+            chk = hexlify(cipher[-12:]).decode()
+            data = hexlify(cipher[:-12]).decode()
+            entry = f"$krb5tgs${etype}${username}${realm}$*{spn_fmt}*${chk}${data}"
         else:
-            nxc_logger.error(f"Skipping {decoded_tgs['ticket']['sname']['name-string'][0]}/{decoded_tgs['ticket']['sname']['name-string'][1]} due to incompatible e-type {decoded_tgs['ticket']['enc-part']['etype']:d}")
+            nxc_logger.fail(f"Skipping {decoded_tgs['ticket']['sname']['name-string'][0]}/{decoded_tgs['ticket']['sname']['name-string'][1]} due to incompatible e-type {decoded_tgs['ticket']['enc-part']['etype']:d}")
 
         return entry