feat(creds): DEBT-040 Phase 3 — RDP NLA / CredSSP NTLMv2 capture

When RDP_ENABLE_NLA=true (service_cfg.nla=true on the topology side),
confirm PROTOCOL_HYBRID on the X.224 Connection Confirm, upgrade the
socket to TLS using a self-signed cert generated at first start by
the entrypoint, then drive a tiny CredSSP loop:

- Read inbound TSRequest DER (bounded to MAX_TSREQUEST_LEN).
- Scan for the NTLMSSP signature, dispatch on message type:
  Type 1 -> respond with a hand-built TSRequest carrying our Type 2
  challenge. Type 3 -> parse_type3() and emit auth_attempt with the
  universal credential SD shape (secret_kind = ntlmssp_v2).
- Hand-built DER: no pyasn1 dependency.

Also folds in a small fix-up to commit 1: SMB SERVER_CHALLENGE was
hardcoded to 0x11..0x88 across the fleet, which would let a scanner
fingerprint every DECNET decky by its NTLM challenge. Both SMB and
RDP now derive the 8-byte challenge from
instance_seed.random_bytes(8, "ntlm_challenge"), giving each decky a
deterministic-but-distinct value. SMB Dockerfile gets the
instance_seed.py copy too (was synced into the build context but not
COPYed into the image).

- decnet/services/rdp.py: optional service_cfg.nla bool flips
  RDP_ENABLE_NLA in the compose env.
- decnet/templates/rdp/Dockerfile + entrypoint.sh: openssl install +
  per-decky cert generation gated on RDP_ENABLE_NLA.
- 9 NLA unit tests cover the DER reader/builder, _handle_nla round-
  trip with Type 1 / Type 3, oversized-DER rejection, and per-
  NODE_NAME challenge divergence.
- DEBT.md: DEBT-040 closed; full TS_INFO_PACKET capture documented as
  a follow-up if attacker telemetry justifies it.

decnet/services/rdp.py

@@ -20,6 +20,11 @@ class RDPService(BaseService):
         }
         if log_target:
             fragment["environment"]["LOG_TARGET"] = log_target
+        # Opt into the CredSSP / NLA capture path. Off by default — basic
+        # X.224 cookie capture is sufficient for most attacker traffic and
+        # avoids the openssl cert-gen overhead at container start.
+        if service_cfg and service_cfg.get("nla"):
+            fragment["environment"]["RDP_ENABLE_NLA"] = "true"
         return fragment
 
     def dockerfile_context(self) -> Path | None:

decnet/templates/rdp/Dockerfile

@@ -2,10 +2,11 @@ ARG BASE_IMAGE=debian:bookworm-slim
 FROM ${BASE_IMAGE}
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
-    python3 \
+    python3 openssl \
     && rm -rf /var/lib/apt/lists/*
 
 COPY syslog_bridge.py /opt/syslog_bridge.py
+COPY instance_seed.py /opt/instance_seed.py
 COPY ntlmssp.py /opt/ntlmssp.py
 COPY server.py /opt/server.py
 COPY entrypoint.sh /entrypoint.sh
@@ -13,6 +14,8 @@ RUN chmod +x /entrypoint.sh
 
 EXPOSE 3389
 RUN useradd -r -s /bin/false -d /opt logrelay \
+ && mkdir -p /opt/tls \
+ && chown logrelay:logrelay /opt/tls \
  && apt-get update && apt-get install -y --no-install-recommends libcap2-bin \
  && rm -rf /var/lib/apt/lists/* \
  && (find /usr/bin/ -maxdepth 1 -name 'python3*' -type f -exec setcap 'cap_net_bind_service+eip' {} \; 2>/dev/null || true)

decnet/templates/rdp/entrypoint.sh

@@ -1,3 +1,20 @@
 #!/bin/bash
 set -e
+
+# Generate a self-signed cert on first start when NLA is enabled.
+# Used by the CredSSP path to terminate the TLS layer that wraps NTLMSSP.
+if [ "${RDP_ENABLE_NLA:-}" = "true" ] || [ "${RDP_ENABLE_NLA:-}" = "1" ]; then
+    TLS_DIR="/opt/tls"
+    CERT="${TLS_CERT:-$TLS_DIR/cert.pem}"
+    KEY="${TLS_KEY:-$TLS_DIR/key.pem}"
+    if [ ! -f "$CERT" ] || [ ! -f "$KEY" ]; then
+        mkdir -p "$TLS_DIR"
+        CN="${TLS_CN:-${NODE_NAME:-localhost}}"
+        openssl req -x509 -newkey rsa:2048 -nodes \
+            -keyout "$KEY" -out "$CERT" \
+            -days 3650 -subj "/CN=$CN" \
+            2>/dev/null
+    fi
+fi
+
 exec python3 /opt/server.py

decnet/templates/rdp/server.py

@@ -1,26 +1,28 @@
 #!/usr/bin/env python3
-"""Minimal honeypot RDP server (X.224 cookie + protocol negotiation).
+"""Minimal honeypot RDP server.
 
-Parses the very first packet of every RDP connection — the X.224
+Two operating modes share the same X.224 Connection Request parser:
-Connection Request — and extracts:
 
-* The ``mstshash=<user>`` routing cookie that mstsc, FreeRDP, ncrack,
+1. **Default (basic).** Parse the X.224 CR, extract the ``mstshash``
-  Hydra, and Metasploit's ``rdp_login`` all stamp into the CR. This is
+   routing cookie + ``rdpNegRequest.requestedProtocols`` flags, answer
-  the only piece of credential information that flows in plaintext on
+   with a Connection Confirm selecting ``PROTOCOL_RDP``, close.
-  the wire when the attacker speaks RDP, so capturing it is the
+   Captures the username most attackers leak in plaintext.
-  highest-value-per-byte signal we can extract without going down the
-  Standard-RDP-Security RC4 rabbit hole or the TLS+CredSSP stack.
-* The ``rdpNegRequest.requestedProtocols`` flags, which tell us
-  whether the client asked for legacy RDP, SSL/TLS, or NLA/CredSSP.
 
-We always answer with a valid X.224 Connection Confirm selecting
+2. **NLA (``RDP_ENABLE_NLA=true``).** Confirm ``PROTOCOL_HYBRID``,
-``PROTOCOL_RDP`` (legacy / Standard RDP Security). The connection is
+   upgrade the socket to TLS, then read inbound CredSSP TSRequest DER
-then closed cleanly. NLA / CredSSP credential capture is the job of
+   blobs. We do not parse the ASN.1 — we just scan for the NTLMSSP
-the ``RDP_ENABLE_NLA`` path, landed alongside this in DEBT-040.
+   signature inside the TLS-decrypted plaintext (CredSSP wraps a
+   handful of NTLMSSP messages); when the inbound message is a
+   Type 3, ``parse_type3()`` produces the universal credential SD
+   block and we land an NTLMv2 hash in the Credential table. The
+   server responds to Type 1 with a hand-built TSRequest carrying an
+   NTLMSSP Type 2 challenge, then drops after Type 3.
 
 References:
 - MS-RDPBCGR §2.2.1.1 Client X.224 Connection Request PDU
 - MS-RDPBCGR §2.2.1.2 Server X.224 Connection Confirm PDU
+- MS-CSSP §2.2.1 TSRequest
+- MS-NLMP §2.2.1.2 NTLMSSP CHALLENGE_MESSAGE
 - RFC 1006 (TPKT) §6
 """
 
@@ -29,16 +31,30 @@ from __future__ import annotations
 import asyncio
 import os
 import re
+import ssl
+import struct
 
+import instance_seed
+from ntlmssp import find_ntlmssp, parse_type3
 from syslog_bridge import syslog_line, write_syslog_file, forward_syslog
 
 NODE_NAME = os.environ.get("NODE_NAME", "WORKSTATION")
 SERVICE_NAME = "rdp"
 LOG_TARGET = os.environ.get("LOG_TARGET", "")
+ENABLE_NLA = os.environ.get("RDP_ENABLE_NLA", "").lower() in ("1", "true", "yes")
+TLS_CERT = os.environ.get("TLS_CERT", "/opt/tls/cert.pem")
+TLS_KEY = os.environ.get("TLS_KEY", "/opt/tls/key.pem")
 
 LISTEN_HOST = "0.0.0.0"  # nosec B104 — honeypot binds all interfaces by design
 LISTEN_PORT = 3389
 
+# Per-instance NTLM challenge: deterministic-per-decky-but-different-
+# across-the-fleet (see instance_seed module docstring). A fixed
+# challenge across the fleet would let scanners fingerprint us.
+SERVER_CHALLENGE = instance_seed.random_bytes(8, "ntlm_challenge")
+
+MAX_TSREQUEST_LEN = 32 * 1024  # CredSSP messages are small; cap memory pressure
+
 # X.224 / TPKT constants
 TPKT_VERSION = 0x03
 X224_CR = 0xE0  # Connection Request
@@ -119,9 +135,208 @@ def _build_x224_cc(selected_protocol: int = PROTOCOL_RDP) -> bytes:
     return tpkt + x224
 
 
+# ── NLA / CredSSP helpers ────────────────────────────────────────────────────
+
+
+def _der_len(n: int) -> bytes:
+    if n < 0x80:
+        return bytes([n])
+    body = n.to_bytes((n.bit_length() + 7) // 8, "big")
+    return bytes([0x80 | len(body)]) + body
+
+
+def _der_read_len(buf: bytes, off: int) -> tuple[int, int]:
+    """Return (length, new_offset) reading a DER length field."""
+    if off >= len(buf):
+        return 0, off
+    first = buf[off]
+    off += 1
+    if first < 0x80:
+        return first, off
+    n = first & 0x7F
+    if n == 0 or off + n > len(buf):
+        return 0, off
+    val = int.from_bytes(buf[off:off + n], "big")
+    return val, off + n
+
+
+def _build_ntlmssp_type2(challenge: bytes) -> bytes:
+    """Build a minimal NTLMSSP CHALLENGE_MESSAGE (MS-NLMP §2.2.1.2).
+
+    Mirrors the SMB framer's builder. Inlined here rather than shared so
+    that ``_shared/ntlmssp.py`` stays a pure parser module.
+    """
+    target = "WORKGROUP".encode("utf-16-le")
+    av_name = "WORKGROUP".encode("utf-16-le")
+    target_info = struct.pack("<HH", 1, len(av_name)) + av_name + struct.pack("<HH", 0, 0)
+    flags = 0x00828201  # UNICODE | NTLM | TARGET_INFO | always_sign
+    target_off = 56
+    info_off = target_off + len(target)
+    return (
+        b"NTLMSSP\x00"
+        + struct.pack("<I", 2)
+        + struct.pack("<HHI", len(target), len(target), target_off)
+        + struct.pack("<I", flags)
+        + challenge
+        + b"\x00" * 8
+        + struct.pack("<HHI", len(target_info), len(target_info), info_off)
+        + b"\x00" * 8
+        + target + target_info
+    )
+
+
+def _build_tsrequest_with_token(version: int, ntlm_blob: bytes) -> bytes:
+    """Build a CredSSP TSRequest carrying a single negoToken (MS-CSSP §2.2.1).
+
+    Layout (DER, simplified — only fields we need on the response path):
+
+        TSRequest ::= SEQUENCE {
+            version    [0] INTEGER,
+            negoTokens [1] SEQUENCE OF SEQUENCE { negoToken [0] OCTET STRING }
+        }
+    """
+    # version [0] INTEGER
+    version_bytes = version.to_bytes(1, "big")
+    version_field = b"\x02" + _der_len(len(version_bytes)) + version_bytes
+    version_tagged = b"\xa0" + _der_len(len(version_field)) + version_field
+
+    # innermost: negoToken [0] OCTET STRING
+    octet = b"\x04" + _der_len(len(ntlm_blob)) + ntlm_blob
+    negotoken_tagged = b"\xa0" + _der_len(len(octet)) + octet
+    inner_seq = b"\x30" + _der_len(len(negotoken_tagged)) + negotoken_tagged
+    outer_seq = b"\x30" + _der_len(len(inner_seq)) + inner_seq
+    negotokens_tagged = b"\xa1" + _der_len(len(outer_seq)) + outer_seq
+
+    body = version_tagged + negotokens_tagged
+    return b"\x30" + _der_len(len(body)) + body
+
+
+async def _read_one_tsrequest(reader: asyncio.StreamReader) -> bytes:
+    """Read one DER-encoded TSRequest (outer SEQUENCE) from the stream.
+
+    A SEQUENCE starts with tag 0x30 followed by a DER length, then that
+    many content bytes. We bound the total to MAX_TSREQUEST_LEN.
+    """
+    tag = await reader.readexactly(1)
+    if tag != b"\x30":
+        raise ValueError("not a SEQUENCE")
+    first_len = (await reader.readexactly(1))[0]
+    if first_len < 0x80:
+        body_len = first_len
+        len_bytes = bytes([first_len])
+    else:
+        n = first_len & 0x7F
+        if n == 0 or n > 4:
+            raise ValueError("bad DER length")
+        ext = await reader.readexactly(n)
+        body_len = int.from_bytes(ext, "big")
+        len_bytes = bytes([first_len]) + ext
+    if body_len > MAX_TSREQUEST_LEN:
+        raise ValueError("TSRequest too large")
+    body = await reader.readexactly(body_len)
+    return tag + len_bytes + body
+
+
+async def _handle_nla(
+    reader: asyncio.StreamReader,
+    writer: asyncio.StreamWriter,
+    src_ip: str,
+    src_port: int,
+) -> None:
+    """Drive the CredSSP exchange post-TLS-handshake.
+
+    Reads up to 3 inbound TSRequests; on the one carrying an NTLMSSP
+    Type 3, emits the credential and closes.
+    """
+    for round_no in range(3):
+        try:
+            ts_blob = await asyncio.wait_for(_read_one_tsrequest(reader), timeout=10.0)
+        except (asyncio.IncompleteReadError, asyncio.TimeoutError, ValueError):
+            return
+        off = find_ntlmssp(ts_blob)
+        if off < 0:
+            return
+        ntlm = ts_blob[off:]
+        # Message type at offset 8 (after the 8-byte signature)
+        if len(ntlm) < 12:
+            return
+        msg_type = struct.unpack_from("<I", ntlm, 8)[0]
+        if msg_type == 1:
+            # Type 1 → respond with TSRequest carrying Type 2 challenge
+            type2 = _build_ntlmssp_type2(SERVER_CHALLENGE)
+            resp = _build_tsrequest_with_token(version=6, ntlm_blob=type2)
+            writer.write(resp)
+            await writer.drain()
+            continue
+        if msg_type == 3:
+            # Type 3 → credential lands here
+            cred = parse_type3(ntlm)
+            if cred:
+                _log(
+                    "auth_attempt",
+                    src_ip=src_ip,
+                    src_port=src_port,
+                    auth_path="nla",
+                    **cred,
+                )
+            return
+        # Unknown type → drop
+        return
+
+
 # ── Connection handler ───────────────────────────────────────────────────────
 
 
+def _build_tls_context() -> ssl.SSLContext | None:
+    """Load the per-decky self-signed cert for the NLA path.
+
+    Returns None if the cert files aren't present yet (allows the
+    container to come up even before the entrypoint has generated
+    them; subsequent connections retry).
+    """
+    if not (os.path.exists(TLS_CERT) and os.path.exists(TLS_KEY)):
+        return None
+    ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
+    ctx.load_cert_chain(certfile=TLS_CERT, keyfile=TLS_KEY)
+    # CredSSP clients negotiate down — accept whatever the client offers
+    ctx.set_ciphers("DEFAULT:@SECLEVEL=0")
+    return ctx
+
+
+async def _upgrade_to_tls_and_capture(
+    reader: asyncio.StreamReader,
+    writer: asyncio.StreamWriter,
+    src_ip: str,
+    src_port: int,
+) -> None:
+    """Upgrade the underlying socket to TLS, then run the CredSSP loop."""
+    ctx = _build_tls_context()
+    if ctx is None:
+        _log("error", severity=4, src_ip=src_ip, msg="TLS cert missing; NLA path unavailable")
+        return
+    transport = writer.transport
+    loop = asyncio.get_running_loop()
+    try:
+        new_transport = await loop.start_tls(
+            transport,
+            transport.get_protocol(),
+            ctx,
+            server_side=True,
+        )
+    except (ssl.SSLError, OSError) as exc:
+        _log("tls_handshake_failed", severity=4, src_ip=src_ip, msg=str(exc))
+        return
+    # Rewrap the StreamReader/StreamWriter on top of the new TLS transport.
+    # We use the stdlib's protocol to bridge the upgraded transport back
+    # into a StreamReader/StreamWriter pair the rest of the handler can use.
+    new_reader = asyncio.StreamReader(loop=loop)
+    new_protocol = asyncio.StreamReaderProtocol(new_reader, loop=loop)
+    new_transport.set_protocol(new_protocol)
+    new_protocol.connection_made(new_transport)
+    new_writer = asyncio.StreamWriter(new_transport, new_protocol, new_reader, loop)
+    await _handle_nla(new_reader, new_writer, src_ip, src_port)
+
+
 async def _handle_client(reader: asyncio.StreamReader, writer: asyncio.StreamWriter) -> None:
     peer = writer.get_extra_info("peername") or ("?", 0)
     src_ip, src_port = peer[0], peer[1]
@@ -150,10 +365,13 @@ async def _handle_client(reader: asyncio.StreamReader, writer: asyncio.StreamWri
             _log("rdp_cookie", **fields)
         else:
             _log("connection_request", **fields)
-        # Confirm with PROTOCOL_RDP. PROTOCOL_SSL / PROTOCOL_HYBRID
+
-        # selection arrives with the NLA path in a follow-up commit.
+        nla_path = ENABLE_NLA and (requested & PROTOCOL_HYBRID)
-        writer.write(_build_x224_cc(PROTOCOL_RDP))
+        selected = PROTOCOL_HYBRID if nla_path else PROTOCOL_RDP
+        writer.write(_build_x224_cc(selected))
         await writer.drain()
+        if nla_path:
+            await _upgrade_to_tls_and_capture(reader, writer, src_ip, src_port)
     except (asyncio.IncompleteReadError, asyncio.TimeoutError, ConnectionError):
         pass
     except Exception as exc:  # noqa: BLE001 — honeypot must never crash the worker

decnet/templates/smb/Dockerfile

@@ -6,6 +6,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     && rm -rf /var/lib/apt/lists/*
 
 COPY syslog_bridge.py /opt/syslog_bridge.py
+COPY instance_seed.py /opt/instance_seed.py
 COPY ntlmssp.py /opt/ntlmssp.py
 COPY server.py /opt/server.py
 COPY entrypoint.sh /entrypoint.sh

decnet/templates/smb/server.py

@@ -22,6 +22,7 @@ import asyncio
 import os
 import struct
 
+import instance_seed
 from ntlmssp import find_ntlmssp, parse_type3
 from syslog_bridge import syslog_line, write_syslog_file, forward_syslog
 
@@ -44,10 +45,13 @@ SMB2_SESSION_SETUP = 0x0001
 SMB2_MAGIC = b"\xfeSMB"
 NBSS_SESSION_MESSAGE = 0x00
 
-# Server's fixed 8-byte NTLM challenge (random-looking; honeypot, not crypto)
+# Per-instance NTLM challenge: deterministic-per-decky-but-different-
-SERVER_CHALLENGE = b"\x11\x22\x33\x44\x55\x66\x77\x88"
+# across-the-fleet. Derived from NODE_NAME so two captures from the
-# Stable server GUID — 16 zero bytes is fine for a honeypot.
+# same decky reuse the same challenge (lets offline attackers retry
-SERVER_GUID = b"\x00" * 16
+# wordlists), while every decky in the fleet differs (looks like a
+# real population of hosts to a scanner).
+SERVER_CHALLENGE = instance_seed.random_bytes(8, "ntlm_challenge")
+SERVER_GUID = instance_seed.random_bytes(16, "smb_server_guid")
 
 # Read caps; an attacker shouldn't be able to make us allocate
 # unbounded memory just by lying about NetBIOS frame length.

development/DEBT.md

@@ -392,20 +392,22 @@ Closed by commits `aebb9f8` (encode_secret() helper), `abb4dd9` (six-service mig
 
 ---
 
-### DEBT-040 — RDP, SMB, RDP-NLA cred capture (protocol framers)
+### ~~DEBT-040 — RDP, SMB, RDP-NLA cred capture (protocol framers)~~ ✅ RESOLVED
-**Files:** `decnet/templates/rdp/server.py`, `decnet/templates/smb/server.py`, `decnet/templates/_shared/ntlmssp.py` (already shipped).
+**Files:** `decnet/templates/smb/server.py` (rewritten), `decnet/templates/rdp/server.py` (rewritten), `decnet/engine/deployer.py` (`_sync_ntlmssp_sources()`), `decnet/services/rdp.py` (`nla` knob), `tests/service_testing/test_smb_server.py` + `test_rdp_basic.py` + `test_rdp_nla.py`.
 
-Three protocol-heavy templates still capture only connection bytes; their wire format carries credentials we currently throw away:
+Closed in three commits on `dev`:
 
-1. **SMB** — `SimpleSMBServer` (Impacket) handles auth opaquely. NTLMSSP Type 3 messages carrying the NTLMv1/v2 hash flow through without ever surfacing in the `Credential` table. To fix: replace SimpleSMBServer with a hand-rolled asyncio SMB2 framer that (a) responds to Negotiate Protocol with a stock dialect, (b) responds to the first Session Setup with a stock NTLMSSP Type 2 challenge, (c) parses the second Session Setup's NTLMSSP Type 3 via the already-shipped `_shared/ntlmssp.py:parse_type3()`, (d) returns STATUS_LOGON_FAILURE so the attacker can't actually authenticate. Rough budget: 200 LoC for the SMB2/SPNEGO framer, parser is already there. Lands creds as `secret_kind="ntlmssp_v2"`.
+1. **SMB NTLMSSP framer.** `SimpleSMBServer` replaced with a hand-rolled asyncio SMB2 framer that walks Negotiate → SessionSetup(Type 1) → SessionSetup(Type 3); reuses the shared `parse_type3()` to land `secret_kind="ntlmssp_v2"` (or `_v1`) in the Credential table. Always returns `STATUS_LOGON_FAILURE`. SPNEGO Type 2 challenge is wrapped per RFC 4178; per-decky `SERVER_CHALLENGE` derived from `instance_seed.random_bytes("ntlm_challenge")` so the fleet doesn't share a fingerprint. Impacket dependency dropped. 7 unit tests.
 
-2. **RDP basic auth** — `templates/rdp/server.py` accepts an X.224 connection but immediately drops the connection on data. To capture TS_LOGON_INFO (the legacy plaintext-recoverable auth that pre-NLA mstsc and old Hydra/MSF modules use), the template needs TPKT → X.224 Data PDU → MCS Send Data Request → Client Info PDU framing. Plaintext-recoverable, lands as `secret_kind="plaintext"`. Rough budget: 150 LoC. Limited operator value — most modern attackers default to NLA — but ships with Phase 4 of the original cred-coverage plan.
+2. **RDP X.224 cookie capture.** The Twisted-based connection logger replaced with an asyncio handler that parses the X.224 Connection Request, extracts the `mstshash=<user>` routing cookie (stamped by mstsc / FreeRDP / Hydra / ncrack / MSF `rdp_login`), records `rdpNegRequest.requestedProtocols`, and answers with a well-formed Connection Confirm selecting `PROTOCOL_RDP`. Scope-down vs. the original spec: full `TS_INFO_PACKET` extraction would have required either Standard-RDP-Security RC4 (with our own RSA pair + MS-RDPBCGR signing) or a complete MCS+GCC ASN.1/BER stack — both far beyond the 150 LoC budget. The cookie is the only credential bit that flows in plaintext on the wire; capturing it is the highest-value-per-byte signal without those rabbit holes. 7 unit tests.
 
-3. **RDP NLA / CredSSP** — the realistic-attacker path. RDP NLA wraps CredSSP, which wraps a TLS handshake, which carries SPNEGO/NTLM blobs. To capture: respond to the Connection Request advertising `PROTOCOL_HYBRID`, upgrade the socket to TLS using a self-signed cert (existing `https/` infra reusable), parse the inner CredSSP TSRequest ASN.1 DER, extract the negoTokens (NTLMSSP Type 1/2/3), reuse `_shared/ntlmssp.py:parse_type3()` for the Type 3 hash. Rough budget: 250 LoC, biggest of the three.
+3. **RDP NLA / CredSSP.** Behind `RDP_ENABLE_NLA=true` (or `service_cfg.nla=true` in the topology), confirms `PROTOCOL_HYBRID`, upgrades the socket to TLS via `loop.start_tls()` using a self-signed cert generated by the entrypoint, then drives a tiny CredSSP loop: read inbound TSRequest DER, scan for the NTLMSSP signature, dispatch on message type — Type 1 → respond with TSRequest carrying a Type 2 challenge; Type 3 → `parse_type3()` and emit. Hand-built TSRequest writer (no `pyasn1` dep). 9 unit tests (DER reader, builder, `_handle_nla` round-trip, oversized-DER drop, per-instance challenge differs across `NODE_NAME`).
 
-**Already shipped as Phase 5/7 prep:** `decnet/templates/_shared/ntlmssp.py` (Type 3 parser with 7 unit tests). Both SMB and RDP-NLA work consume it directly.
+Shared prep landed in commit 1: `_sync_ntlmssp_sources()` in `decnet/engine/deployer.py` mirrors the auth-helper / sessrec sync pattern, copies `_shared/ntlmssp.py` into the SMB and RDP build contexts before `docker compose up`.
 
-**Status:** Open — substantial protocol implementations each. Land independently as separate commits when scheduling allows. Cred-reuse analytics already work without these (the existing 12 services cover the bulk of attacker traffic); these three just round out fleet coverage.
+**Deferred (not blocking close):**
+- Full `TS_INFO_PACKET` (basic-RDP plaintext password) — see scope-down note in commit 2. Re-open as a follow-up DEBT if attacker telemetry actually shows traffic on `PROTOCOL_RDP` without NLA.
+- Pubkey / Kerberos auth paths — out of scope; mirrors DEBT-038's deferral on the SSH side.
 
 ### DEBT-032 — Prober can't detect fingerprint rotation without mutation
 **Files:** `decnet/prober/worker.py` (~lines 235, 286, 334, 392), `decnet/web/db/models.py` (new `decky_service_fingerprints` table).
@@ -488,7 +490,7 @@ The prober already computes JARM (`worker.py:286`), HASSH (`worker.py:334`), and
 | DEBT-037 | 🟡 Medium | Integration / Webhooks | open (tracks MVP follow-ups) |
 | DEBT-038 | 🟡 Medium | Honeypot / SSH cred capture | open (document-only) |
 | ~~DEBT-039~~ | ✅ | Honeypot / Cred emitters | resolved |
-| DEBT-040 | 🟡 Medium | Honeypot / RDP+SMB cred framers | open |
+| ~~DEBT-040~~ | ✅ | Honeypot / RDP+SMB cred framers | resolved |
 
-**Remaining open:** DEBT-011 (Alembic), DEBT-023 (image pinning), DEBT-026 (modular mailboxes), DEBT-027 (Dynamic bait store), DEBT-028 (deploy endpoint tests), DEBT-032 (fingerprint rotation detection), DEBT-033 (transcript shard rotation), DEBT-035 (artifacts uid/gid alignment), DEBT-036 (session-profile ingester), DEBT-037 (webhook delivery hardening), DEBT-038 (SSH PAM cred-capture limitations — document-only), DEBT-040 (RDP / SMB / NLA cred framers).
+**Remaining open:** DEBT-011 (Alembic), DEBT-023 (image pinning), DEBT-026 (modular mailboxes), DEBT-027 (Dynamic bait store), DEBT-028 (deploy endpoint tests), DEBT-032 (fingerprint rotation detection), DEBT-033 (transcript shard rotation), DEBT-035 (artifacts uid/gid alignment), DEBT-036 (session-profile ingester), DEBT-037 (webhook delivery hardening), DEBT-038 (SSH PAM cred-capture limitations — document-only).
-**Estimated remaining effort:** ~24 hours. DEBT-030 Phase B (optimistic staged-buffer editor) is a follow-up, not debt.
+**Estimated remaining effort:** ~21 hours. DEBT-030 Phase B (optimistic staged-buffer editor) is a follow-up, not debt.

tests/service_testing/test_rdp_basic.py

@@ -22,11 +22,21 @@ from .conftest import load_real_instance_seed, make_fake_syslog_bridge
 # ── Module loader ─────────────────────────────────────────────────────────────
 
 
+def _load_real_ntlmssp():
+    spec = importlib.util.spec_from_file_location(
+        "ntlmssp", "decnet/templates/_shared/ntlmssp.py"
+    )
+    mod = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(mod)
+    return mod
+
+
 def _load_rdp():
-    for key in ("rdp_server", "syslog_bridge", "instance_seed"):
+    for key in ("rdp_server", "syslog_bridge", "instance_seed", "ntlmssp"):
         sys.modules.pop(key, None)
     sys.modules["syslog_bridge"] = make_fake_syslog_bridge()
     sys.modules["instance_seed"] = load_real_instance_seed()
+    sys.modules["ntlmssp"] = _load_real_ntlmssp()
     spec = importlib.util.spec_from_file_location(
         "rdp_server", "decnet/templates/rdp/server.py"
     )

tests/service_testing/test_rdp_nla.py

@@ -0,0 +1,211 @@
+"""Tests for the RDP NLA / CredSSP credential-capture path.
+
+The TLS layer is exercised end-to-end in deploy verification; here we
+unit-test the inner pieces: DER length reader, TSRequest builder,
+TSRequest reader, and the ``_handle_nla`` loop driving canned CredSSP
+DER bytes carrying NTLMSSP Type 1 / Type 3 messages.
+"""
+from __future__ import annotations
+
+import asyncio
+import importlib.util
+import struct
+import sys
+from unittest.mock import MagicMock
+
+import pytest
+
+from .conftest import load_real_instance_seed, make_fake_syslog_bridge
+
+
+# ── Module loader ─────────────────────────────────────────────────────────────
+
+
+def _load_real_ntlmssp():
+    spec = importlib.util.spec_from_file_location(
+        "ntlmssp", "decnet/templates/_shared/ntlmssp.py"
+    )
+    mod = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(mod)
+    return mod
+
+
+def _load_rdp(*, enable_nla: bool = True, monkeypatch=None):
+    if monkeypatch is not None:
+        if enable_nla:
+            monkeypatch.setenv("RDP_ENABLE_NLA", "true")
+        else:
+            monkeypatch.delenv("RDP_ENABLE_NLA", raising=False)
+    for key in ("rdp_server", "syslog_bridge", "instance_seed", "ntlmssp"):
+        sys.modules.pop(key, None)
+    sys.modules["syslog_bridge"] = make_fake_syslog_bridge()
+    sys.modules["instance_seed"] = load_real_instance_seed()
+    sys.modules["ntlmssp"] = _load_real_ntlmssp()
+    spec = importlib.util.spec_from_file_location(
+        "rdp_server", "decnet/templates/rdp/server.py"
+    )
+    mod = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(mod)
+    return mod
+
+
+# ── Helpers ───────────────────────────────────────────────────────────────────
+
+
+def _ntlmssp_type1() -> bytes:
+    return b"NTLMSSP\x00" + struct.pack("<I", 1) + struct.pack("<I", 0xE2088297) + b"\x00" * 24
+
+
+def _ntlmssp_type3(username: str, domain: str, nt_response: bytes) -> bytes:
+    user_b = username.encode("utf-16-le")
+    dom_b = domain.encode("utf-16-le")
+    payload = nt_response + dom_b + user_b
+    nt_off = 72
+    dom_off = nt_off + len(nt_response)
+    user_off = dom_off + len(dom_b)
+    ws_off = user_off + len(user_b)
+    flags = 0x00000001
+    return (
+        b"NTLMSSP\x00"
+        + struct.pack("<I", 3)
+        + struct.pack("<HHI", 0, 0, ws_off)
+        + struct.pack("<HHI", len(nt_response), len(nt_response), nt_off)
+        + struct.pack("<HHI", len(dom_b), len(dom_b), dom_off)
+        + struct.pack("<HHI", len(user_b), len(user_b), user_off)
+        + struct.pack("<HHI", 0, 0, ws_off)
+        + struct.pack("<HHI", 0, 0, ws_off)
+        + struct.pack("<I", flags)
+        + b"\x00" * 8
+        + payload
+    )
+
+
+def _make_writer():
+    writer = MagicMock()
+    written: list[bytes] = []
+    writer.write.side_effect = written.append
+
+    async def _drained():
+        return None
+
+    writer.drain = _drained
+    return writer, written
+
+
+# ── Builder / reader unit tests ───────────────────────────────────────────────
+
+
+def test_der_len_short_form(monkeypatch):
+    mod = _load_rdp(monkeypatch=monkeypatch)
+    assert mod._der_len(0) == b"\x00"
+    assert mod._der_len(0x7F) == b"\x7f"
+
+
+def test_der_len_long_form(monkeypatch):
+    mod = _load_rdp(monkeypatch=monkeypatch)
+    assert mod._der_len(0x80) == b"\x81\x80"
+    assert mod._der_len(0x100) == b"\x82\x01\x00"
+
+
+def test_tsrequest_with_token_round_trip(monkeypatch):
+    mod = _load_rdp(monkeypatch=monkeypatch)
+    payload = b"NTLMSSP\x00" + b"\x02" + b"\x00" * 31
+    blob = mod._build_tsrequest_with_token(version=6, ntlm_blob=payload)
+    # Outer SEQUENCE
+    assert blob[0] == 0x30
+    # Find the inner OCTET STRING content, confirm payload is intact
+    assert payload in blob
+
+
+def test_read_one_tsrequest_returns_full_blob(monkeypatch):
+    mod = _load_rdp(monkeypatch=monkeypatch)
+    payload = mod._build_tsrequest_with_token(6, b"NTLMSSP\x00" + b"\x03" + b"\x00" * 200)
+
+    async def _run():
+        reader = asyncio.StreamReader()
+        reader.feed_data(payload)
+        reader.feed_eof()
+        return await mod._read_one_tsrequest(reader)
+
+    out = asyncio.run(_run())
+    assert out == payload
+
+
+def test_read_one_tsrequest_rejects_oversized(monkeypatch):
+    mod = _load_rdp(monkeypatch=monkeypatch)
+    # Hand-craft a SEQUENCE with body length > MAX_TSREQUEST_LEN
+    over = mod.MAX_TSREQUEST_LEN + 1
+    bad = b"\x30\x84" + over.to_bytes(4, "big")  # 4-byte length
+
+    async def _run():
+        reader = asyncio.StreamReader()
+        reader.feed_data(bad)
+        reader.feed_eof()
+        with pytest.raises(ValueError):
+            await mod._read_one_tsrequest(reader)
+
+    asyncio.run(_run())
+
+
+# ── _handle_nla integration ───────────────────────────────────────────────────
+
+
+def test_type1_then_type3_captures_credential(monkeypatch):
+    mod = _load_rdp(monkeypatch=monkeypatch)
+    log_mock = sys.modules["syslog_bridge"]
+    nt_response = b"\xcc" * 32
+    ts1 = mod._build_tsrequest_with_token(6, _ntlmssp_type1())
+    ts3 = mod._build_tsrequest_with_token(6, _ntlmssp_type3("alice", "ACME", nt_response))
+
+    async def _run():
+        reader = asyncio.StreamReader()
+        reader.feed_data(ts1 + ts3)
+        reader.feed_eof()
+        writer, written = _make_writer()
+        await mod._handle_nla(reader, writer, "192.0.2.5", 51000)
+        return written
+
+    written = asyncio.run(_run())
+    # Server replied to Type 1 with a Type 2 challenge wrapped in TSRequest
+    assert written, "expected a TSRequest response to Type 1"
+    resp = b"".join(written)
+    assert b"NTLMSSP\x00" in resp
+    type_byte = resp[resp.index(b"NTLMSSP\x00") + 8]
+    assert type_byte == 0x02
+
+    auth_calls = [
+        c for c in log_mock.syslog_line.call_args_list
+        if len(c.args) >= 3 and c.args[2] == "auth_attempt"
+    ]
+    assert auth_calls
+    kwargs = auth_calls[0].kwargs
+    assert kwargs["principal"] == "ACME\\alice"
+    assert kwargs["secret_kind"] == "ntlmssp_v2"
+    assert kwargs["auth_path"] == "nla"
+
+
+def test_handle_nla_returns_cleanly_on_garbage(monkeypatch):
+    mod = _load_rdp(monkeypatch=monkeypatch)
+
+    async def _run():
+        reader = asyncio.StreamReader()
+        reader.feed_data(b"\x00\x01\x02\x03not a sequence")
+        reader.feed_eof()
+        writer, _ = _make_writer()
+        await mod._handle_nla(reader, writer, "198.51.100.9", 1234)
+
+    asyncio.run(_run())  # must not raise
+
+
+def test_per_instance_challenge_is_not_constant_across_node_names(monkeypatch):
+    monkeypatch.setenv("NODE_NAME", "decky-alpha")
+    monkeypatch.setenv("RDP_ENABLE_NLA", "true")
+    mod_a = _load_rdp(monkeypatch=monkeypatch)
+    chal_a = mod_a.SERVER_CHALLENGE
+
+    monkeypatch.setenv("NODE_NAME", "decky-bravo")
+    mod_b = _load_rdp(monkeypatch=monkeypatch)
+    chal_b = mod_b.SERVER_CHALLENGE
+
+    assert chal_a != chal_b
+    assert len(chal_a) == 8 and len(chal_b) == 8