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Python ​

Validate Python network behavior under the Secure Sandbox.

Objectives ​

  • Enforce deny-by-default egress and designated proxy routing across Python HTTP stacks and raw sockets.
  • Prove localhost/loopback isolation and failure of proxy-bypass tactics.
  • Validate IPv6 parity, DNS-over-HTTPS evasion, WebSocket/gRPC/raw sockets denial.
  • Demonstrate inbound isolation: the host cannot reach services started inside the sandbox.

Preconditions ​

  • Windows target with Turbo Launcher and Secure Sandbox.
  • Python 3.11+ available in the sandbox (any recent Python 3.x is acceptable).
  • Optional libraries inside the sandbox (when scenarios reference them): requests, aiohttp, websockets, grpcio, urllib3, and requests[socks] if testing SOCKS proxies.

Controls Under Test ​

  • runtime.networking.egressDefaultAction (deny by default)
  • Designated proxy enforcement and env-var bypass resistance (proxyEnforced, HTTP(S)_PROXY, NO_PROXY, client trust_env settings)
  • TLS certificate pinning and SNI checks (no interception with wrong CA)
  • Protocol gating: alpn (e.g., QUIC/HTTP3), CONNECT-to-non-proxy denial
  • Loopback and inbound isolation between Sandbox and host
  • Required audit fields: action, reason, proxyEnforced, alpn/protocol, ipVersion, rule.id, integrity.hash

Test Scenarios ​

IDCanonical IDScenarioProcedureExpected Outcome
SCEN-TOOL-PYTHON-01NET-ISOLATE-01Loopback isolationpython -c "import socket; s=socket.socket(); s.settimeout(5); s.connect(('127.0.0.1', 80))"Denied/refused; host loopback unreachable from sandbox. Audit: action: deny.
SCEN-TOOL-PYTHON-02NET-ISOLATE-02Inbound isolation (Host→Sandbox)In sandbox: python -m http.server 8080 --bind 0.0.0.0.
From host: curl http://<sandbox-ip>:8080		Connection fails (timeout/refused). No inbound exposure.
SCEN-TOOL-PYTHON-03NET-EGRESS-01Direct IP egresspython -c "import requests; requests.get('http://1.1.1.1', timeout=5)"Denied per default-deny. Audit: action: deny.
SCEN-TOOL-PYTHON-04NET-EGRESS-05Env proxy vars (unauthorized)set HTTPS_PROXY=http://127.0.0.1:8080 && python -c "import requests; requests.get('https://example.com', timeout=5)"Denied; reason: unauthorizedProxy, proxyEnforced: true.
SCEN-TOOL-PYTHON-05NET-EGRESS-06NO_PROXY bypass attemptset NO_PROXY=* && python -c "import requests; requests.get('https://example.com', timeout=5)"Denied; reason: proxyBypassAttempt, proxyEnforced: true.
SCEN-TOOL-PYTHON-06NET-EGRESS-07Client bypass (disable trust_env)python -c "import requests; s=requests.Session(); s.trust_env=False; s.get('https://example.com', timeout=5)"Denied; bypass refused at sandbox boundary.
SCEN-TOOL-PYTHON-07NET-EGRESS-09Proxy outage (fail-closed)Take the designated proxy down; then requests.get('https://example.com').Denied; no direct fallback. Audit: reason: proxyUnavailable.
SCEN-TOOL-PYTHON-08NET-EGRESS-10Proxy TLS pinning/identityIntercept proxy TLS with wrong CA; requests.get('https://example.com').Denied. Audit: reason: certMismatch or pinningFailed.
SCEN-TOOL-PYTHON-09NET-EGRESS-11IPv6 direct egresspython -c "import requests; requests.get('https://[2606:4700:4700::1111]/', timeout=5)"Denied unless explicitly allowed; ipVersion: 6.
SCEN-TOOL-PYTHON-10NET-EGRESS-12CONNECT to non-proxypython -c "import urllib3; pm=urllib3.ProxyManager('https://nonproxy.example:443'); pm.request('GET','https://target.example')"Denied. Audit: reason: destNotProxy.
SCEN-TOOL-PYTHON-11NET-EGRESS-13Raw TCP socketpython -c "import socket; s=socket.socket(); s.settimeout(5); s.connect(('1.1.1.1',443))"Denied by namespace/firewall.
SCEN-TOOL-PYTHON-12NET-EGRESS-05Stdlib urllib bypasspython -c "import urllib.request as u; u.build_opener(u.ProxyHandler({})).open('https://example.com', timeout=5)"Denied; bypass refused.
SCEN-TOOL-PYTHON-13NET-EGRESS-07aiohttp trust_env bypass attemptpython -c "import asyncio,aiohttp; async def r():\n async with aiohttp.ClientSession(trust_env=False) as s: await s.get('https://example.com', timeout=5);\n asyncio.run(r())"Denied; proxy enforced at boundary.
SCEN-TOOL-PYTHON-14NET-PROTO-07websockets WSSpython -c "import asyncio,websockets; async def r():\n async with websockets.connect('wss://echo.websocket.events') as ws: await ws.send('x'); await ws.recv()\n asyncio.run(r())"Denied (no UDP/QUIC/WS bypass).
SCEN-TOOL-PYTHON-15NET-PROTO-07gRPC over TLSCreate grpc.insecure_channel('public.host:443') and call a stub.Denied; direct tunnels not allowed.
SCEN-TOOL-PYTHON-16NET-EGRESS-05Loopback proxy attemptset HTTPS_PROXY=http://127.0.0.1:8888 && python -c "import requests; requests.get('https://example.com', timeout=5)"Denied unless loopback proxy is designated (should not be).
SCEN-TOOL-PYTHON-17NET-EGRESS-07aiohttp trust_env bypass attemptpython -c "import asyncio,aiohttp; async def r():\n async with aiohttp.ClientSession(trust_env=False) as s: await s.get('https://example.com', timeout=5);\n asyncio.run(r())"Denied; proxy enforced at boundary.
SCEN-TOOL-PYTHON-18NET-PROTO-07websockets WSSpython -c "import asyncio,websockets; async def r():\n async with websockets.connect('wss://echo.websocket.events') as ws: await ws.send('x'); await ws.recv()\n asyncio.run(r())"Denied (no UDP/QUIC/WS bypass).
SCEN-TOOL-PYTHON-19NET-PROTO-07 / NET-EGRESS-13gRPC over TLSCreate grpc.insecure_channel('public.host:443') and call a stub.Denied; direct tunnels not allowed.
SCEN-TOOL-PYTHON-20NET-EGRESS-05Loopback proxy attemptset HTTPS_PROXY=http://127.0.0.1:8888 && python -c "import requests; requests.get('https://example.com', timeout=5)"Denied unless that loopback proxy is designated by policy (should not be).

Representative Python Snippets ​

Direct IP (requests):

python
import requests
requests.get('http://1.1.1.1', timeout=5)

NO_PROXY bypass attempt:

python
import os, requests
os.environ['NO_PROXY'] = '*'
requests.get('https://example.com', timeout=5)

Raw IPv4 and IPv6 sockets:

python
import socket

s4 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s4.settimeout(5)
s4.connect(('1.1.1.1', 443))

s6 = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
s6.settimeout(5)
s6.connect(('2606:4700:4700::1111', 443, 0, 0))

aiohttp trust_env bypass attempt:

python
import asyncio, aiohttp

async def run():
    async with aiohttp.ClientSession(trust_env=False) as session:
        async with session.get('https://example.com', timeout=5) as resp:
            print(resp.status)

asyncio.run(run())

Evidence Requirements ​

  • Audit category: network.
  • Required fields: action, reason (for example, unauthorizedProxy, proxyBypassAttempt, destNotProxy, proxyUnavailable, certMismatch/pinningFailed), proxyEnforced, protocol/alpn, ipVersion.
  • For isolation attempts, include scope: internal when applicable.

Troubleshooting ​

  • Some libraries cache connection pools; run attempts twice if the first try hits DNS cache or connection reuse.
  • Ensure environment variables (for example, HTTP_PROXY, HTTPS_PROXY, NO_PROXY) do not mislead manual testing—policy must enforce the proxy regardless of client settings.
  • If optional libraries are not present, focus on stdlib (urllib.request, socket) and requests scenarios.

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