feat(url_guard): SSRF and path traversal guard for scraper inputs

- Add url_guard.py with validate_url() that rejects:
  - Non-HTTP schemes (file://, ftp://, javascript:)
  - Private/reserved IP ranges (RFC 1918, loopback, CGNAT, link-local)
  - Internal hostnames (localhost, kubernetes, docker, metadata, etc.)
  - Embedded credentials in URLs
  - Path traversal sequences (.., %2e%2e%2f, %%2e%%2e%%2f)
- Integrate into scraper.scrape() and UltimateScraper.scrape()
- Use typed InvalidRequestError for structured API error responses
- Add 24 tests covering all rejection cases and valid URLs
- 560 tests passing, ruff clean
This commit is contained in:
Crypto Rug Munch 2026-07-03 12:00:40 +02:00
parent da31a1f9e7
commit 2970c15dbb
4 changed files with 275 additions and 0 deletions

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@ -19,8 +19,10 @@ import httpx
import trafilatura
from trafilatura.settings import use_config
from errors import InvalidRequestError
from settings import settings
from stealth_engine import StealthEngine
from url_guard import validate_url
USER_AGENTS = [
"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36",
@ -281,6 +283,10 @@ class PryScraper:
async def scrape(self, url: str, options: dict | None = None) -> dict[str, Any]:
if not url or not url.startswith(("http://", "https://")):
return {"status": "error", "url": url, "error": "Invalid URL", "content": ""}
try:
validate_url(url)
except InvalidRequestError as e:
return {"status": "error", "url": url, "error": str(e), "content": ""}
opts = options or {}

107
tests/test_url_guard.py Normal file
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@ -0,0 +1,107 @@
"""Tests for SSRF and path-traversal guard."""
from __future__ import annotations
import pytest
from errors import InvalidRequestError
from url_guard import validate_url
class TestValidateURL:
def test_accepts_normal_https(self):
result = validate_url("https://example.com/page")
assert result == "https://example.com/page"
def test_accepts_normal_http(self):
result = validate_url("http://example.com/page")
assert result == "http://example.com/page"
def test_accepts_https_with_path_and_query(self):
url = "https://api.example.com/v1/data?key=val&page=2#section"
result = validate_url(url)
assert result == url
def test_rejects_empty_url(self):
with pytest.raises(InvalidRequestError):
validate_url("")
def test_rejects_ftp_scheme(self):
with pytest.raises(InvalidRequestError):
validate_url("ftp://example.com/file")
def test_rejects_file_scheme(self):
with pytest.raises(InvalidRequestError):
validate_url("file:///etc/passwd")
def test_rejects_javascript_scheme(self):
with pytest.raises(InvalidRequestError):
validate_url("javascript:alert(1)")
def test_rejects_localhost_hostname(self):
with pytest.raises(InvalidRequestError):
validate_url("http://localhost:8080/admin")
def test_rejects_localhost_ip(self):
with pytest.raises(InvalidRequestError):
validate_url("http://127.0.0.1:8080/admin")
def test_rejects_private_ip_10_dot(self):
with pytest.raises(InvalidRequestError):
validate_url("http://10.0.0.1/admin")
def test_rejects_private_ip_192_168(self):
with pytest.raises(InvalidRequestError):
validate_url("http://192.168.1.1/admin")
def test_rejects_private_ip_172(self):
with pytest.raises(InvalidRequestError):
validate_url("http://172.16.0.1/admin")
def test_rejects_internal_hostname(self):
with pytest.raises(InvalidRequestError):
validate_url("http://internal.corp/admin")
def test_rejects_kubernetes_metadata(self):
with pytest.raises(InvalidRequestError):
validate_url("http://kubernetes.default.svc.cluster.local")
def test_rejects_embedded_credentials(self):
with pytest.raises(InvalidRequestError):
validate_url("http://user:pass@example.com/")
def test_rejects_path_traversal_simple(self):
with pytest.raises(InvalidRequestError):
validate_url("https://example.com/../../etc/passwd")
def test_rejects_path_traversal_encoded(self):
with pytest.raises(InvalidRequestError):
validate_url("https://example.com/%2e%2e%2fetc/passwd")
def test_rejects_path_traversal_double_encoded(self):
with pytest.raises(InvalidRequestError):
validate_url("https://example.com/%252e%252e%252fetc")
def test_rejects_tailscale_ip(self):
with pytest.raises(InvalidRequestError):
validate_url("http://100.64.0.1/")
def test_rejects_empty_hostname(self):
with pytest.raises(InvalidRequestError):
validate_url("http:///path")
def test_rejects_docker_host(self):
with pytest.raises(InvalidRequestError):
validate_url("http://docker/container")
def test_rejects_metadata_google(self):
with pytest.raises(InvalidRequestError):
validate_url("http://metadata.google.internal/")
def test_rejects_link_local_ipv6(self):
with pytest.raises(InvalidRequestError):
validate_url("http://[fe80::1]/")
def test_rejects_loopback_ipv6(self):
with pytest.raises(InvalidRequestError):
validate_url("http://[::1]/")

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@ -18,7 +18,9 @@ import time
from typing import Any, ClassVar
from urllib.parse import urlparse
from errors import InvalidRequestError
from resilience import registry
from url_guard import validate_url
logger = logging.getLogger(__name__)
@ -111,6 +113,11 @@ class UltimateScraper:
Will try up to 10 strategies until one succeeds."""
opts = options or {}
errors: list[str] = []
try:
validate_url(url)
except InvalidRequestError as e:
return {"status": "error", "url": url, "error": str(e)}
proxy_url = self._resolve_proxy_url(opts)

155
url_guard.py Normal file
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@ -0,0 +1,155 @@
"""SSRF and path traversal guard for Pry scrapers.
Validates URLs before scraping to prevent:
- SSRF attacks (private IPs, loopback, internal hosts)
- Path traversal (../, encoded variants)
- File:// or other non-HTTP schemes
- DNS rebinding risks (common internal hostnames)
"""
# SPDX-License-Identifier: MIT
# Copyright (c) 2026 Rug Munch Media LLC
#
# Part of Pry — https://git.rugmunch.io/RugMunchMedia/pryscraper
# Licensed under MIT. See LICENSE.
from __future__ import annotations
import ipaddress
import logging
import re
import socket
from urllib.parse import urlparse
logger = logging.getLogger(__name__)
# Private/reserved IP ranges (RFC 1918, RFC 6598, RFC 4193, link-local, loopback)
_PRIVATE_NETS: list[str] = [
"127.0.0.0/8", # loopback
"10.0.0.0/8", # RFC 1918
"172.16.0.0/12", # RFC 1918
"192.168.0.0/16", # RFC 1918
"100.64.0.0/10", # RFC 6598 (CGNAT)
"169.254.0.0/16", # link-local
"fc00::/7", # RFC 4193 (ULA)
"fe80::/10", # link-local IPv6
"::1/128", # IPv6 loopback
]
# Common internal hostnames that suggest SSRF targeting
_INTERNAL_HOST_RE = re.compile(
r"^(.+\.)?"
r"(localhost|internal|intranet|private|corp|home|router|gateway|"
r"metadata|kubernetes|kube|docker|consul|nomad|vault|"
r"elasticsearch|redis|mysql|postgres|memcached|"
r"grafana|prometheus|alertmanager|"
r"minio|s3|storage|db|database|"
r"admin|dashboard|management|"
r"apiserver|etcd|"
r"tailscale|100\.\d+\.\d+\.\d+)"
r"(\..+)?$",
re.IGNORECASE,
)
# Blocked URL schemes
_ALLOWED_SCHEMES = {"http", "https"}
# Path traversal patterns
_TRAVERSAL_RE = re.compile(
r"(?:^|/)\.\.(?:/|%2[fF]|\\|$)"
r"|%2[eE]%2[eE]"
r"|%252[eE]%252[eE]%252[fF]"
r"|\.\.(?:/|\\|$)"
)
def validate_url(url: str, *, resolve_dns: bool = False) -> str:
"""Validate a URL for SSRF and path-traversal safety.
Args:
url: The URL to validate.
resolve_dns: If True, perform a DNS lookup to check that the resolved
IP is not in a private range. This adds latency and cannot
be async here, so it defaults to False.
Returns:
The validated URL (unchanged).
Raises:
InvalidRequestError: If the URL is unsafe.
"""
if not url:
raise _error("URL is empty", url)
parsed = urlparse(url)
# Reject non-HTTP schemes
if parsed.scheme not in _ALLOWED_SCHEMES:
raise _error(
f"URL scheme {parsed.scheme} is not allowed (only http/https)",
url,
)
# Reject URLs with embedded credentials
if parsed.username or parsed.password:
raise _error("URL must not contain embedded credentials (user:password@)", url)
hostname = parsed.hostname or ""
# Reject empty hostnames
if not hostname:
raise _error("URL must have a valid hostname", url)
# Reject raw IP: check if it is a private/reserved address
try:
ip = ipaddress.ip_address(hostname)
for net in _PRIVATE_NETS:
if ip in ipaddress.ip_network(net):
raise _error(
f"URL resolves to a private/reserved IP range ({net})",
url,
)
except ValueError:
# Not an IP address — continue with hostname checks
pass
# Reject internal/sensitive hostnames
if _INTERNAL_HOST_RE.match(hostname):
raise _error(
f"URL hostname {hostname} appears to be an internal resource",
url,
)
# Reject DNS resolution to private IPs (opt-in)
if resolve_dns:
try:
addrs = socket.getaddrinfo(hostname, None)
for _family, _, _, _, sockaddr in addrs:
addr = sockaddr[0]
try:
ip = ipaddress.ip_address(addr)
for net in _PRIVATE_NETS:
if ip in ipaddress.ip_network(net):
raise _error(
f"URL resolves to private IP {addr} ({net})",
url,
)
except ValueError:
continue
except OSError as e:
logger.debug("dns_lookup_failed", extra={"hostname": hostname, "error": str(e)})
# Check path for traversal attempts
path = parsed.path + parsed.params + parsed.query + parsed.fragment
if _TRAVERSAL_RE.search(path):
raise _error("URL contains path traversal sequences", url)
return url
def _error(message: str, url: str) -> Exception:
"""Build a structured InvalidRequestError."""
from errors import InvalidRequestError
logger.warning("url_guard_rejected", extra={"url": url, "reason": message})
return InvalidRequestError(message, details={"url": url, "reason": message})