anti
988732f4f9
Some checks failed
CI / Test (pytest) (3.11) (push) Has been cancelled
CI / Test (pytest) (3.12) (push) Has been cancelled
Security / SAST (bandit) (push) Has been cancelled
Security / Dependency audit (pip-audit) (push) Has been cancelled
CI / Lint (ruff) (push) Has been cancelled
97 lines
3.2 KiB
Python
97 lines
3.2 KiB
Python
#!/usr/bin/env python3
|
|
"""
|
|
VNC (RFB)server.
|
|
Performs the RFB 3.8 handshake, offers VNC authentication, captures the
|
|
24-byte DES-encrypted challenge response, then rejects with "Authentication
|
|
failed". Logs the raw response for offline cracking.
|
|
"""
|
|
|
|
import asyncio
|
|
import os
|
|
from decnet_logging import syslog_line, write_syslog_file, forward_syslog
|
|
|
|
NODE_NAME = os.environ.get("NODE_NAME", "desktop")
|
|
SERVICE_NAME = "vnc"
|
|
LOG_TARGET = os.environ.get("LOG_TARGET", "")
|
|
|
|
# RFB challenge — fixed so captured responses are reproducible
|
|
_CHALLENGE = bytes(range(16)) * 1 + b"\x10\x11\x12\x13\x14\x15\x16\x17" # 24 bytes
|
|
|
|
|
|
|
|
|
|
def _log(event_type: str, severity: int = 6, **kwargs) -> None:
|
|
line = syslog_line(SERVICE_NAME, NODE_NAME, event_type, severity, **kwargs)
|
|
print(line, flush=True)
|
|
write_syslog_file(line)
|
|
forward_syslog(line, LOG_TARGET)
|
|
|
|
|
|
class VNCProtocol(asyncio.Protocol):
|
|
def __init__(self):
|
|
self._transport = None
|
|
self._peer = None
|
|
self._buf = b""
|
|
self._state = "version"
|
|
|
|
def connection_made(self, transport):
|
|
self._transport = transport
|
|
self._peer = transport.get_extra_info("peername", ("?", 0))
|
|
_log("connect", src=self._peer[0], src_port=self._peer[1])
|
|
# Send RFB version
|
|
transport.write(b"RFB 003.008\n")
|
|
|
|
def data_received(self, data):
|
|
self._buf += data
|
|
self._process()
|
|
|
|
def _process(self):
|
|
if self._state == "version":
|
|
if b"\n" not in self._buf:
|
|
return
|
|
line, self._buf = self._buf.split(b"\n", 1)
|
|
client_version = line.decode(errors="replace").strip()
|
|
_log("version", src=self._peer[0], client_version=client_version)
|
|
# Send security types: 1 type = VNC Authentication (2)
|
|
self._transport.write(b"\x01\x02")
|
|
self._state = "security_choice"
|
|
|
|
elif self._state == "security_choice":
|
|
if len(self._buf) < 1:
|
|
return
|
|
chosen = self._buf[0]
|
|
self._buf = self._buf[1:]
|
|
_log("security_choice", src=self._peer[0], type=chosen)
|
|
# Send 16-byte challenge
|
|
self._transport.write(_CHALLENGE[:16])
|
|
self._state = "auth_response"
|
|
|
|
elif self._state == "auth_response":
|
|
if len(self._buf) < 16:
|
|
return
|
|
response = self._buf[:16]
|
|
self._buf = self._buf[16:]
|
|
_log("auth_response", src=self._peer[0], response=response.hex())
|
|
# SecurityResult: 1 = failed
|
|
self._transport.write(b"\x00\x00\x00\x01")
|
|
# Failure reason
|
|
reason = b"Authentication failed"
|
|
import struct
|
|
self._transport.write(struct.pack(">I", len(reason)) + reason)
|
|
self._transport.close()
|
|
|
|
def connection_lost(self, exc):
|
|
_log("disconnect", src=self._peer[0] if self._peer else "?")
|
|
|
|
|
|
async def main():
|
|
_log("startup", msg=f"VNC server starting as {NODE_NAME}")
|
|
loop = asyncio.get_running_loop()
|
|
server = await loop.create_server(VNCProtocol, "0.0.0.0", 5900)
|
|
async with server:
|
|
await server.serve_forever()
|
|
|
|
|
|
if __name__ == "__main__":
|
|
asyncio.run(main())
|