Cobra
ffd384f64b
Replace all sensor.* logger namespaces with __name__ (generic module identifiers instead of discoverable 'sensor.*' prefixes). Change hardcoded 'bb' API user to 'admin' in config and code defaults. Change hardcoded relay_user 'bb' to 'operator' — prevents network profiling from exposing tool identity via SSH config. Fixes #457, #458, #459
379 lines
13 KiB
Python
379 lines
13 KiB
Python
#!/usr/bin/env python3
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"""RDP session monitor — passive RDP connection tracking.
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Parses RDP Connection Request (Cookie field containing username),
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CredSSP/NLA TSRequest structures for NTLM domain\\username extraction,
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and tracks session patterns to identify admin workstations.
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"""
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import logging
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import os
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import socket
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import sqlite3
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import struct
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import threading
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import time
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from collections import defaultdict
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from pathlib import Path
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from typing import Optional
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from modules.base import BaseModule
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logger = logging.getLogger(__name__)
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# NTLM signature for CredSSP extraction
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NTLMSSP_SIGNATURE = b'NTLMSSP\x00'
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NTLM_AUTHENTICATE = 3
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# X.224 Connection Request type
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X224_CONNECTION_REQUEST = 0xE0
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# Admin workstation threshold
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ADMIN_DEST_THRESHOLD = 3
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_DB_INIT = """
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CREATE TABLE IF NOT EXISTS rdp_sessions (
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id INTEGER PRIMARY KEY AUTOINCREMENT,
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timestamp REAL NOT NULL,
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source_ip TEXT NOT NULL,
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dest_ip TEXT NOT NULL,
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username TEXT DEFAULT '',
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domain TEXT DEFAULT '',
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client_hostname TEXT DEFAULT '',
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keyboard_layout TEXT DEFAULT ''
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);
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CREATE INDEX IF NOT EXISTS idx_rdp_src ON rdp_sessions(source_ip);
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CREATE INDEX IF NOT EXISTS idx_rdp_user ON rdp_sessions(username);
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CREATE INDEX IF NOT EXISTS idx_rdp_ts ON rdp_sessions(timestamp);
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"""
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FLUSH_INTERVAL = 30
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class RDPMonitor(BaseModule):
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"""Monitor RDP sessions passively for user/host identification."""
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name = "rdp_monitor"
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module_type = "passive"
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priority = 150
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requires_root = True
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requires_capture_bus = True
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def __init__(self, bus, state, config, engine=None):
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super().__init__(bus, state, config, engine)
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self._capture_bus = None
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self._sub_queue = None
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self._read_thread: Optional[threading.Thread] = None
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self._flush_thread: Optional[threading.Thread] = None
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self._db_path = self._resolve_db_path()
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self._db_conn: Optional[sqlite3.Connection] = None
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self._write_buffer: list[tuple] = []
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self._buffer_lock = threading.Lock()
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# Track admin patterns: src_ip -> set of dest_ips
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self._rdp_targets: dict[str, set] = defaultdict(set)
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self._stats = {
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"packets_processed": 0,
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"connection_requests": 0,
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"credssp_auths": 0,
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"unique_sessions": 0,
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"admin_workstations": 0,
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}
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# ------------------------------------------------------------------
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# BaseModule interface
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# ------------------------------------------------------------------
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def start(self) -> None:
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if self._running:
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return
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self._init_db()
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self._capture_bus = self.config.get("_capture_bus")
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if self._capture_bus is None:
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logger.error("RDPMonitor requires _capture_bus in config")
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return
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self._sub_queue = self._capture_bus.subscribe(
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name=self.name, bpf_filter="port 3389", queue_depth=3000
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)
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self._running = True
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self._start_time = time.time()
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self._pid = os.getpid()
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self._read_thread = threading.Thread(
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target=self._read_loop, daemon=True, name="sensor-rdp-read"
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)
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self._read_thread.start()
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self._flush_thread = threading.Thread(
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target=self._flush_loop, daemon=True, name="sensor-rdp-flush"
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)
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self._flush_thread.start()
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self.state.set_module_status(self.name, "running", pid=self._pid)
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self.bus.emit("MODULE_STARTED", {"module": self.name}, source_module=self.name)
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logger.info("RDPMonitor started")
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def stop(self) -> None:
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if not self._running:
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return
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self._running = False
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if self._capture_bus:
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self._capture_bus.unsubscribe(self.name)
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for t in (self._read_thread, self._flush_thread):
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if t and t.is_alive():
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t.join(timeout=5.0)
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self._flush_buffer()
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if self._db_conn:
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self._db_conn.close()
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self._db_conn = None
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self.state.set_module_status(self.name, "stopped")
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self.bus.emit("MODULE_STOPPED", {"module": self.name}, source_module=self.name)
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logger.info("RDPMonitor stopped — stats: %s", self._stats)
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def status(self) -> dict:
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return {
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"running": self._running,
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"pid": self._pid,
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"uptime": time.time() - self._start_time if self._start_time else 0,
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**self._stats,
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}
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def configure(self, config: dict) -> None:
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self.config.update(config)
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# ------------------------------------------------------------------
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# Packet processing
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# ------------------------------------------------------------------
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def _read_loop(self) -> None:
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while self._running:
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result = self._sub_queue.get(timeout=1.0)
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if result is None:
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continue
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ts, pkt = result
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self._stats["packets_processed"] += 1
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try:
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self._process_packet(pkt, ts)
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except Exception:
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logger.debug("Error processing RDP packet", exc_info=True)
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def _process_packet(self, pkt: bytes, ts: float) -> None:
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"""Extract TCP payload and dispatch to RDP parsers."""
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if len(pkt) < 54:
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return
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ethertype = struct.unpack("!H", pkt[12:14])[0]
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eth_offset = 14
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if ethertype == 0x8100:
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if len(pkt) < 58:
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return
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ethertype = struct.unpack("!H", pkt[16:18])[0]
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eth_offset = 18
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if ethertype != 0x0800:
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return
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ip_header = pkt[eth_offset:]
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if len(ip_header) < 20:
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return
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ihl = (ip_header[0] & 0x0F) * 4
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ip_proto = ip_header[9]
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if ip_proto != 6:
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return
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src_ip = socket.inet_ntoa(ip_header[12:16])
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dst_ip = socket.inet_ntoa(ip_header[16:20])
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if len(ip_header) < ihl + 20:
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return
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src_port, dst_port = struct.unpack("!HH", ip_header[ihl:ihl + 4])
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tcp_data_off = ((ip_header[ihl + 12] >> 4) & 0xF) * 4
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payload = ip_header[ihl + tcp_data_off:]
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if len(payload) < 6:
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return
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# Only process traffic going TO RDP port (client -> server)
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if dst_port == 3389:
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self._parse_rdp_client(payload, src_ip, dst_ip, ts)
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def _parse_rdp_client(self, payload: bytes, src_ip: str, dst_ip: str,
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ts: float) -> None:
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"""Parse client-to-server RDP traffic."""
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# Check for TPKT header (version=3, reserved=0)
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if payload[0] == 0x03 and payload[1] == 0x00:
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self._parse_tpkt(payload, src_ip, dst_ip, ts)
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return
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# Check for NTLMSSP in CredSSP
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if NTLMSSP_SIGNATURE in payload:
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self._parse_credssp_ntlm(payload, src_ip, dst_ip, ts)
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def _parse_tpkt(self, payload: bytes, src_ip: str, dst_ip: str,
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ts: float) -> None:
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"""Parse TPKT + X.224 Connection Request for username cookie."""
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if len(payload) < 11:
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return
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# TPKT: version(1) + reserved(1) + length(2)
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tpkt_len = struct.unpack("!H", payload[2:4])[0]
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# X.224: length indicator(1) + type(1)
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x224_len = payload[4]
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x224_type = payload[5] & 0xF0
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if x224_type != X224_CONNECTION_REQUEST:
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return
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self._stats["connection_requests"] += 1
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# After X.224 header (variable length), look for Cookie field
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# Cookie format: "Cookie: mstshash=username\r\n"
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cookie_data = payload[11:] # Skip past basic X.224 header
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username = ""
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client_hostname = ""
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# Search for mstshash cookie
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cookie_idx = cookie_data.find(b'Cookie: mstshash=')
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if cookie_idx >= 0:
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cookie_start = cookie_idx + 17 # len("Cookie: mstshash=")
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cookie_end = cookie_data.find(b'\r\n', cookie_start)
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if cookie_end > cookie_start:
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username = cookie_data[cookie_start:cookie_end].decode(
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"ascii", errors="replace"
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).strip()
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if username:
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self._rdp_targets[src_ip].add(dst_ip)
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self._stats["unique_sessions"] += 1
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self._check_admin_workstation(src_ip)
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self._record_session(ts, src_ip, dst_ip, username, "", "", "")
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def _parse_credssp_ntlm(self, payload: bytes, src_ip: str, dst_ip: str,
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ts: float) -> None:
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"""Extract NTLM credentials from CredSSP TSRequest."""
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idx = payload.find(NTLMSSP_SIGNATURE)
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if idx < 0 or idx + 12 > len(payload):
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return
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ntlm_data = payload[idx:]
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msg_type = struct.unpack("<I", ntlm_data[8:12])[0]
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if msg_type != NTLM_AUTHENTICATE or len(ntlm_data) < 72:
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return
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username, domain, workstation = self._parse_ntlm_type3(ntlm_data)
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if username:
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self._stats["credssp_auths"] += 1
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self._rdp_targets[src_ip].add(dst_ip)
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self._stats["unique_sessions"] += 1
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self._check_admin_workstation(src_ip)
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self._record_session(ts, src_ip, dst_ip, username, domain, workstation, "")
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def _parse_ntlm_type3(self, data: bytes) -> tuple:
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"""Parse NTLM Type 3 Authenticate for username, domain, workstation."""
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if len(data) < 72:
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return ("", "", "")
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try:
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domain_len = struct.unpack("<H", data[28:30])[0]
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domain_off = struct.unpack("<I", data[32:36])[0]
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user_len = struct.unpack("<H", data[36:38])[0]
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user_off = struct.unpack("<I", data[40:44])[0]
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ws_len = struct.unpack("<H", data[44:46])[0]
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ws_off = struct.unpack("<I", data[48:52])[0]
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domain = ""
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username = ""
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workstation = ""
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if domain_len and domain_off + domain_len <= len(data):
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domain = data[domain_off:domain_off + domain_len].decode(
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"utf-16-le", errors="replace"
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)
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if user_len and user_off + user_len <= len(data):
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username = data[user_off:user_off + user_len].decode(
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"utf-16-le", errors="replace"
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)
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if ws_len and ws_off + ws_len <= len(data):
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workstation = data[ws_off:ws_off + ws_len].decode(
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"utf-16-le", errors="replace"
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)
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return (username, domain, workstation)
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except Exception:
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return ("", "", "")
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def _check_admin_workstation(self, src_ip: str) -> None:
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"""Check if source IP qualifies as admin workstation."""
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targets = self._rdp_targets.get(src_ip, set())
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if len(targets) >= ADMIN_DEST_THRESHOLD:
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current = len([
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ip for ip, dests in self._rdp_targets.items()
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if len(dests) >= ADMIN_DEST_THRESHOLD
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])
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if current > self._stats["admin_workstations"]:
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self._stats["admin_workstations"] = current
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logger.info(
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"Admin workstation detected: %s (RDP to %d hosts)",
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src_ip, len(targets)
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)
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# ------------------------------------------------------------------
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# Database
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# ------------------------------------------------------------------
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def _resolve_db_path(self) -> str:
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base = self.config.get("db_dir", os.path.join(
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os.path.expanduser("~"), ".implant"
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))
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return os.path.join(base, "rdp_monitor.db")
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def _init_db(self) -> None:
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Path(self._db_path).parent.mkdir(parents=True, exist_ok=True)
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self._db_conn = sqlite3.connect(self._db_path, check_same_thread=False)
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self._db_conn.execute("PRAGMA journal_mode=WAL")
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self._db_conn.execute("PRAGMA synchronous=NORMAL")
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self._db_conn.executescript(_DB_INIT)
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self._db_conn.commit()
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def _record_session(self, ts: float, src_ip: str, dst_ip: str,
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username: str, domain: str, client_hostname: str,
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keyboard_layout: str) -> None:
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with self._buffer_lock:
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self._write_buffer.append((
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ts, src_ip, dst_ip, username, domain, client_hostname, keyboard_layout
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))
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def _flush_buffer(self) -> None:
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with self._buffer_lock:
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batch = list(self._write_buffer)
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self._write_buffer.clear()
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if not batch or not self._db_conn:
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return
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try:
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with self._db_conn:
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self._db_conn.executemany(
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"""INSERT INTO rdp_sessions
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(timestamp, source_ip, dest_ip, username, domain,
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client_hostname, keyboard_layout)
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VALUES (?, ?, ?, ?, ?, ?, ?)""",
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batch,
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)
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except Exception:
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logger.exception("Failed to flush RDP sessions")
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def _flush_loop(self) -> None:
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while self._running:
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time.sleep(FLUSH_INTERVAL)
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try:
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self._flush_buffer()
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except Exception:
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logger.exception("Flush loop error")
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