Agent: Try well-known ports before other ports

monkey/common/utils/code_utils.py

@@ -1,5 +1,6 @@
 import queue
-from typing import Any, Dict, List, MutableMapping, Type, TypeVar
+from bisect import bisect_left
+from typing import Any, Dict, List, MutableMapping, Sequence, Type, TypeVar
 
 T = TypeVar("T")
 
@@ -48,3 +49,15 @@ def del_key(mapping: MutableMapping[T, Any], key: T):
         del mapping[key]
     except KeyError:
         pass
+
+
+def in_sorted_sequence(item: Any, seq: Sequence[Any]) -> bool:
+    """
+    Provides fast search in the case that the sequence is sorted.
+
+    :param item: The item to search in the list.
+    :param seq: The sorted sequence in which to search the item.
+    :return: True if the item was found in the list, otherwise false.
+    """
+    i = bisect_left(seq, item)
+    return i != len(seq) and seq[i] == item

monkey/infection_monkey/network/info.py

@@ -3,14 +3,17 @@ import socket
 import struct
 from dataclasses import dataclass
 from ipaddress import IPv4Interface
-from random import randint  # noqa: DUO102
+from random import shuffle  # noqa: DUO102
 from typing import List
 
 import netifaces
 import psutil
 
+from common.utils.code_utils import in_sorted_sequence
 from infection_monkey.utils.environment import is_windows_os
 
+from .ports import COMMON_PORTS
+
 # Timeout for monkey connections
 LOOPBACK_NAME = b"lo"
 SIOCGIFADDR = 0x8915  # get PA address
@@ -119,15 +122,19 @@ else:
 
 
 def get_free_tcp_port(min_range=1024, max_range=65535):
+
+    in_use = sorted([conn.laddr[1] for conn in psutil.net_connections()])
+
+    for port in COMMON_PORTS:
+        if not in_sorted_sequence(port, in_use):
+            return port
+
     min_range = max(1, min_range)
     max_range = min(65535, max_range)
-
-    in_use = [conn.laddr[1] for conn in psutil.net_connections()]
-
-    for i in range(min_range, max_range):
-        port = randint(min_range, max_range)
-
-        if port not in in_use:
+    ports = list(range(min_range, max_range))
+    shuffle(ports)
+    for port in ports:
+        if not in_sorted_sequence(port, in_use):
             return port
 
     return None

monkey/infection_monkey/network/ports.py

@@ -0,0 +1,15 @@
+from typing import List
+
+COMMON_PORTS: List[int] = [
+    1025,  # NFS, IIS
+    1433,  # Microsoft SQL Server
+    1434,  # Microsoft SQL Monitor
+    1720,  # h323q931
+    1723,  # Microsoft PPTP VPN
+    3306,  # mysql
+    3389,  # Windows Terminal Server (RDP)
+    5900,  # vnc
+    6001,  # X11:1
+    8080,  # http-proxy
+    8888,  # sun-answerbook
+]

monkey/tests/unit_tests/common/utils/test_code_utils.py

@@ -1,6 +1,6 @@
 from queue import Queue
 
-from common.utils.code_utils import del_key, queue_to_list
+from common.utils.code_utils import del_key, in_sorted_sequence, queue_to_list
 
 
 def test_empty_queue_to_empty_list():
@@ -40,3 +40,11 @@ def test_del_key__nonexistant_key():
 
     # This test passes if the following call does not raise an error
     del_key(my_dict, key_to_delete)
+
+
+def test_in_sorted_sequence__finds_item():
+    assert in_sorted_sequence(99, range(100))
+
+
+def test_in_sorted_sequence__does_not_find_nonexistent_item():
+    assert not in_sorted_sequence(101, range(100))

monkey/tests/unit_tests/infection_monkey/network/test_info.py

@@ -0,0 +1,40 @@
+from dataclasses import dataclass
+from typing import Tuple
+
+import pytest
+
+from infection_monkey.network.info import get_free_tcp_port
+from infection_monkey.network.ports import COMMON_PORTS
+
+
+@dataclass
+class Connection:
+    laddr: Tuple[str, int]
+
+
+@pytest.mark.parametrize("port", COMMON_PORTS)
+def test_get_free_tcp_port__checks_common_ports(port: int, monkeypatch):
+    unavailable_ports = [Connection(("", p)) for p in COMMON_PORTS if p is not port]
+
+    monkeypatch.setattr(
+        "infection_monkey.network.info.psutil.net_connections", lambda: unavailable_ports
+    )
+    assert get_free_tcp_port() is port
+
+
+def test_get_free_tcp_port__checks_other_ports_if_common_ports_unavailable(monkeypatch):
+    unavailable_ports = [Connection(("", p)) for p in COMMON_PORTS]
+    monkeypatch.setattr(
+        "infection_monkey.network.info.psutil.net_connections", lambda: unavailable_ports
+    )
+
+    assert get_free_tcp_port() is not None
+
+
+def test_get_free_tcp_port__none_if_no_available_ports(monkeypatch):
+    unavailable_ports = [Connection(("", p)) for p in range(65535)]
+    monkeypatch.setattr(
+        "infection_monkey.network.info.psutil.net_connections", lambda: unavailable_ports
+    )
+
+    assert get_free_tcp_port() is None