Files
DECNET/templates/imap/server.py
anti 24f02c3466 fix: resolve all bandit SAST findings in templates/
- Add # nosec B104 to all intentional 0.0.0.0 binds in honeypot servers
  (hardcoded_bind_all_interfaces is by design — deckies must accept attacker connections)
- Add # nosec B101 to assert statements used for protocol validation in ldap/snmp
- Add # nosec B105 to fake SASL placeholder in ldap
- Add # nosec B108 to /tmp usage in smb template
- Exclude root-owned auto-generated decnet_logging.py copies from bandit scan
  via pyproject.toml [tool.bandit] config (synced by _sync_logging_helper at deploy)
2026-04-10 00:24:40 -04:00

84 lines
2.9 KiB
Python

#!/usr/bin/env python3
"""
IMAPserver.
Presents an IMAP4rev1 banner, captures LOGIN credentials (plaintext and
AUTHENTICATE), then returns a NO response. Logs all commands as JSON.
"""
import asyncio
import os
from decnet_logging import syslog_line, write_syslog_file, forward_syslog
NODE_NAME = os.environ.get("NODE_NAME", "mailserver")
SERVICE_NAME = "imap"
LOG_TARGET = os.environ.get("LOG_TARGET", "")
BANNER = f"* OK [{NODE_NAME}] IMAP4rev1 Service Ready\r\n"
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 IMAPProtocol(asyncio.Protocol):
def __init__(self):
self._transport = None
self._peer = None
self._buf = b""
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])
transport.write(BANNER.encode())
def data_received(self, data):
self._buf += data
while b"\n" in self._buf:
line, self._buf = self._buf.split(b"\n", 1)
self._handle_line(line.decode(errors="replace").strip())
def _handle_line(self, line: str):
parts = line.split(None, 2)
if not parts:
return
tag = parts[0]
cmd = parts[1].upper() if len(parts) > 1 else ""
args = parts[2] if len(parts) > 2 else ""
if cmd == "LOGIN":
creds = args.split(None, 1)
username = creds[0].strip('"') if creds else ""
password = creds[1].strip('"') if len(creds) > 1 else ""
_log("auth", src=self._peer[0], username=username, password=password)
self._transport.write(f"{tag} NO [AUTHENTICATIONFAILED] Invalid credentials\r\n".encode())
elif cmd == "CAPABILITY":
self._transport.write(b"* CAPABILITY IMAP4rev1 AUTH=PLAIN AUTH=LOGIN\r\n")
self._transport.write(f"{tag} OK CAPABILITY completed\r\n".encode())
elif cmd == "LOGOUT":
self._transport.write(b"* BYE IMAP4rev1 Server logging out\r\n")
self._transport.write(f"{tag} OK LOGOUT completed\r\n".encode())
self._transport.close()
else:
_log("command", src=self._peer[0], cmd=line[:128])
self._transport.write(f"{tag} BAD Command not recognized\r\n".encode())
def connection_lost(self, exc):
_log("disconnect", src=self._peer[0] if self._peer else "?")
async def main():
_log("startup", msg=f"IMAP server starting as {NODE_NAME}")
loop = asyncio.get_running_loop()
server = await loop.create_server(IMAPProtocol, "0.0.0.0", 143) # nosec B104
async with server:
await server.serve_forever()
if __name__ == "__main__":
asyncio.run(main())