merge: testing → main (reconcile 2-week divergence)

decnet/templates/ftp/server.py

@@ -0,0 +1,144 @@
+#!/usr/bin/env python3
+"""
+FTP server using Twisted's FTP server infrastructure.
+Accepts any credentials, logs all commands and file requests,
+forwards events as JSON to LOG_TARGET if set.
+"""
+
+import os
+from pathlib import Path
+
+from twisted.internet import defer, reactor
+from twisted.protocols.ftp import FTP, FTPFactory, FTPAnonymousShell
+from twisted.python.filepath import FilePath
+from twisted.python import log as twisted_log
+
+import instance_seed as _seed
+from syslog_bridge import (
+    encode_secret,
+    forward_syslog,
+    syslog_line,
+    write_syslog_file,
+)
+
+NODE_NAME = os.environ.get("NODE_NAME", "ftpserver")
+SERVICE_NAME   = "ftp"
+LOG_TARGET = os.environ.get("LOG_TARGET", "")
+PORT = int(os.environ.get("PORT", "21"))
+
+# Per-instance daemon identity. Fleet-wide "vsFTPd 3.0.3" is an instant
+# fingerprint of an unmaintained honeypot — real shops run a mix.
+_FTP_BANNER_CHOICES = [
+    "220 (vsFTPd 3.0.3)",
+    "220 (vsFTPd 3.0.5)",
+    "220 ProFTPD 1.3.7a Server ready.",
+    "220 ProFTPD 1.3.6 Server ready.",
+    "220 Pure-FTPd Service ready.",
+]
+BANNER = os.environ.get("FTP_BANNER") or _seed.pick(_FTP_BANNER_CHOICES)
+
+# Accept approximately this fraction of logins. Real anon-accessible
+# servers succeed often; credential-harvesting scanners hitting every
+# possible user/pass pair should still see plausible failures.
+_LOGIN_SUCCESS_RATE = float(os.environ.get("FTP_LOGIN_SUCCESS_RATE", "0.9"))
+
+# Optional override — if set to "never", ALL logins fail (realistic for a
+# server with anonymous disabled). Handy for producing server diversity
+# across the fleet.
+_LOGIN_MODE = os.environ.get("FTP_LOGIN_MODE", "").strip().lower()
+
+
+def _log(event_type: str, severity: int = 6, **kwargs) -> None:
+    line = syslog_line(SERVICE_NAME, NODE_NAME, event_type, severity, **kwargs)
+    write_syslog_file(line)
+    forward_syslog(line, LOG_TARGET)
+
+
+def _setup_bait_fs() -> str:
+    """Generate a per-instance bait filesystem.
+
+    No shared paths across deckies (/tmp/ftp_bait was identical on every
+    host), no tell-tale 'super_secret_admin_pw' strings. Filenames, byte
+    counts, and inline values are all derived from the per-decky seed, so
+    two honeypots never serve byte-identical files yet each stays stable
+    across restarts."""
+    bait_dir = Path(f"/tmp/ftp-{_seed.instance_hex(6, 'ftp-bait-dir')}")
+    bait_dir.mkdir(parents=True, exist_ok=True)
+
+    company = _seed.pick(["acme", "contoso", "northwind", "initech", "globex", "hooli"])
+    env = _seed.pick(["prod", "stage", "backup", "archive"])
+    year = _seed.rng.randint(2022, 2024)
+    month = _seed.rng.randint(1, 12)
+
+    # Realistic-looking rotating backups. Sizes vary per instance.
+    for idx in range(_seed.rng.randint(2, 5)):
+        tag = f"{year}{month:02d}{_seed.rng.randint(1, 28):02d}"
+        size = _seed.rng.randint(2048, 32768)
+        (bait_dir / f"{company}-{env}-{tag}.tar.gz").write_bytes(
+            b"\x1f\x8b\x08\x00" + _seed.random_bytes(size - 4, f"tar-{idx}")
+        )
+
+    # A plausible README that looks like legacy ops notes, NOT a credential
+    # dump. No "password = ..." strings — those are a dead giveaway.
+    (bait_dir / "README.txt").write_text(
+        f"{company} {env} drop area\n"
+        f"Rotation: keep last 14, nightly rsync from db{_seed.rng.randint(1,9)}.{env}\n"
+        f"Contact: ops-{env}@{company}.internal\n"
+    )
+    (bait_dir / ".htaccess").write_text("Options -Indexes\n")
+
+    return str(bait_dir)
+
+
+_BAIT_PATH = _setup_bait_fs()
+
+
+class ServerFTP(FTP):
+    def connectionMade(self):
+        peer = self.transport.getPeer()
+        _log("connection", src_ip=peer.host, src_port=peer.port)
+        super().connectionMade()
+
+    def ftp_USER(self, username):
+        self._server_user = username
+        _log("user", username=username)
+        return super().ftp_USER(username)
+
+    def ftp_PASS(self, password):
+        _u = getattr(self, "_server_user", "?")
+        _log("auth_attempt", username=_u, principal=_u, **encode_secret(password))
+        # Decide whether this attempt succeeds. Unseeded randomness so
+        # scanners can't predict which creds will "work".
+        import random as _rand
+        if _LOGIN_MODE == "never":
+            accept = False
+        elif _LOGIN_MODE == "always":
+            accept = True
+        else:
+            accept = _rand.random() < _LOGIN_SUCCESS_RATE
+        if not accept:
+            return defer.succeed((530, "Login incorrect."))
+        self.state = self.AUTHED
+        self._user = getattr(self, "_server_user", "anonymous")
+        self.shell = FTPAnonymousShell(FilePath(_BAIT_PATH))
+        return defer.succeed((230, "Login successful."))
+
+    def ftp_RETR(self, path):
+        _log("download_attempt", path=path)
+        return super().ftp_RETR(path)
+
+    def connectionLost(self, reason):
+        peer = self.transport.getPeer()
+        _log("disconnect", src_ip=peer.host, src_port=peer.port)
+        super().connectionLost(reason)
+
+
+class ServerFTPFactory(FTPFactory):
+    protocol = ServerFTP
+    welcomeMessage = BANNER
+
+if __name__ == "__main__":
+    twisted_log.startLoggingWithObserver(lambda e: None, setStdout=False)
+    _log("startup", msg=f"FTP server starting as {NODE_NAME} on port {PORT}")
+    reactor.listenTCP(PORT, ServerFTPFactory())
+    reactor.run()