Files
DECNET/decnet/templates/http/server.py
anti 3fb84ac5d0 feat(templates): per-instance stealth via instance_seed in service servers
Every service template now pulls version strings, cluster/node UUIDs, auth
salts, greeting banners, and uptime from the seeded per-instance RNG instead
of hard-coded defaults. Scanners sweeping the fleet now see legitimately
diverging fingerprints per decky while each decky's own responses stay
internally consistent across restarts.

Covers elasticsearch, ftp, http, https, ldap, mongodb, mqtt, mssql, mysql,
postgres, redis, and smtp templates.
2026-04-22 09:24:16 -04:00

147 lines
5.1 KiB
Python

#!/usr/bin/env python3
"""
HTTP service emulator using Flask.
Accepts all requests, logs every detail (method, path, headers, body),
and responds with configurable pages. Forwards events as JSON to LOG_TARGET if set.
"""
import json
import logging
import os
from pathlib import Path
from flask import Flask, request, send_from_directory
from werkzeug.serving import make_server, WSGIRequestHandler
import instance_seed as _seed
from syslog_bridge import syslog_line, write_syslog_file, forward_syslog
logging.getLogger("werkzeug").setLevel(logging.ERROR)
NODE_NAME = os.environ.get("NODE_NAME", "webserver")
SERVICE_NAME = "http"
LOG_TARGET = os.environ.get("LOG_TARGET", "")
PORT = int(os.environ.get("PORT", "80"))
# Per-instance Server header. Every decky running one identical Apache
# version string is a one-query fleet discovery for any scanner.
# Distribution shaped toward currently-deployed-in-the-wild versions.
_SERVER_CHOICES = [
"Apache/2.4.41 (Ubuntu)",
"Apache/2.4.52 (Ubuntu)",
"Apache/2.4.54 (Debian)",
"Apache/2.4.56 (Debian)",
"Apache/2.4.57 (Debian)",
"Apache/2.4.58 (Ubuntu)",
"Apache/2.4.59 (Debian)",
"nginx/1.18.0 (Ubuntu)",
"nginx/1.22.1",
"nginx/1.24.0 (Ubuntu)",
"nginx/1.25.3",
]
SERVER_HEADER = os.environ.get("SERVER_HEADER") or _seed.pick(_SERVER_CHOICES)
RESPONSE_CODE = int(os.environ.get("RESPONSE_CODE", "403"))
FAKE_APP = os.environ.get("FAKE_APP", "")
EXTRA_HEADERS = json.loads(os.environ.get("EXTRA_HEADERS", "{}"))
CUSTOM_BODY = os.environ.get("CUSTOM_BODY", "")
FILES_DIR = os.environ.get("FILES_DIR", "")
_FAKE_APP_BODIES: dict[str, str] = {
"apache_default": (
"<!DOCTYPE HTML PUBLIC \"-//IETF//DTD HTML 2.0//EN\">\n"
"<html><head><title>Apache2 Debian Default Page</title></head>\n"
"<body><h1>Apache2 Debian Default Page</h1>\n"
"<p>It works!</p></body></html>"
),
"nginx_default": (
"<!DOCTYPE html><html><head><title>Welcome to nginx!</title></head>\n"
"<body><h1>Welcome to nginx!</h1>\n"
"<p>If you see this page, the nginx web server is successfully installed.</p>\n"
"</body></html>"
),
"wordpress": (
"<!DOCTYPE html><html><head><title>WordPress &rsaquo; Error</title></head>\n"
"<body id=\"error-page\"><div class=\"wp-die-message\">\n"
"<h1>Error establishing a database connection</h1></div></body></html>"
),
"phpmyadmin": (
"<!DOCTYPE html><html><head><title>phpMyAdmin</title></head>\n"
"<body><form method=\"post\" action=\"index.php\">\n"
"<input type=\"text\" name=\"pma_username\" />\n"
"<input type=\"password\" name=\"pma_password\" />\n"
"<input type=\"submit\" value=\"Go\" /></form></body></html>"
),
"iis_default": (
"<!DOCTYPE html><html><head><title>IIS Windows Server</title></head>\n"
"<body><h1>IIS Windows Server</h1>\n"
"<p>Welcome to Internet Information Services</p></body></html>"
),
}
app = Flask(__name__)
@app.after_request
def _fix_server_header(response):
response.headers["Server"] = SERVER_HEADER
return response
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)
@app.before_request
def log_request():
_log(
"request",
method=request.method,
path=request.path,
remote_addr=request.remote_addr,
headers=json.dumps(dict(request.headers)),
body=request.get_data(as_text=True)[:512],
)
@app.route("/", defaults={"path": ""})
@app.route("/<path:path>", methods=["GET", "POST", "PUT", "DELETE", "PATCH", "OPTIONS", "HEAD"])
def catch_all(path):
# Serve static files directory if configured
if FILES_DIR and path:
files_path = Path(FILES_DIR) / path
if files_path.is_file():
return send_from_directory(FILES_DIR, path)
# Select response body: custom > fake_app preset > default 403
if CUSTOM_BODY:
body = CUSTOM_BODY
elif FAKE_APP and FAKE_APP in _FAKE_APP_BODIES:
body = _FAKE_APP_BODIES[FAKE_APP]
else:
body = (
"<!DOCTYPE HTML PUBLIC \"-//IETF//DTD HTML 2.0//EN\">\n"
"<html><head>\n"
"<title>403 Forbidden</title>\n"
"</head><body>\n"
"<h1>Forbidden</h1>\n"
"<p>You don't have permission to access this resource.</p>\n"
"<hr>\n"
f"<address>{SERVER_HEADER} Server at {NODE_NAME} Port 80</address>\n"
"</body></html>\n"
)
headers = {"Content-Type": "text/html", **EXTRA_HEADERS}
return body, RESPONSE_CODE, headers
class _SilentHandler(WSGIRequestHandler):
"""Suppress Werkzeug's Server header so Flask's after_request is the sole source."""
def version_string(self) -> str:
return ""
if __name__ == "__main__":
_log("startup", msg=f"HTTP server starting as {NODE_NAME}")
srv = make_server("0.0.0.0", PORT, app, request_handler=_SilentHandler) # nosec B104
srv.serve_forever()