Expert in browser automation using Chrome DevTools Protocol (CDP) and WebDriver. Specializes in secure web automation, testing, and scraping with proper credential handling, domain restrictions, and audit logging. HIGH-RISK skill due to web access and data handling.
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npx tessl skill review --optimize ./skills/browser-automation/SKILL.mdRisk Level: HIGH - Web access, credential handling, data extraction, network requests
You are an expert in browser automation with deep expertise in:
# tests/test_browser_automation.py
import pytest
from playwright.sync_api import Page, expect
class TestSecureBrowserAutomation:
"""Test secure browser automation with pytest-playwright."""
def test_blocks_banking_domains(self, automation):
"""Test that banking domains are blocked."""
with pytest.raises(SecurityError, match="URL blocked"):
automation.navigate("https://chase.com")
def test_allows_permitted_domains(self, automation):
"""Test navigation to allowed domains."""
automation.navigate("https://example.com")
assert "Example" in automation.page.title()
def test_blocks_password_fields(self, automation):
"""Test that password field filling is blocked."""
automation.navigate("https://example.com/form")
with pytest.raises(SecurityError, match="password"):
automation.fill('input[type="password"]', "secret")
def test_rate_limiting_enforced(self, automation):
"""Test rate limiting prevents abuse."""
for _ in range(60):
automation.check_request()
with pytest.raises(RateLimitError):
automation.check_request()
@pytest.fixture
def automation():
"""Provide configured SecureBrowserAutomation instance."""
auto = SecureBrowserAutomation(
domain_allowlist=['example.com'],
permission_tier='standard'
)
auto.start_session()
yield auto
auto.close()# Implement just enough to pass tests
class SecureBrowserAutomation:
def navigate(self, url: str):
if not self._validate_url(url):
raise SecurityError(f"URL blocked: {url}")
self.page.goto(url)After tests pass, refactor to add:
# Run all browser automation tests
pytest tests/test_browser_automation.py -v --headed
# Run with coverage
pytest tests/test_browser_automation.py --cov=src/automation --cov-report=term-missing
# Run security-specific tests
pytest tests/test_browser_automation.py -k "security" -v# BAD - Creates new browser for each test
def test_page_one():
browser = playwright.chromium.launch()
page = browser.new_page()
page.goto("https://example.com/one")
browser.close()
def test_page_two():
browser = playwright.chromium.launch() # Slow startup again
page = browser.new_page()
page.goto("https://example.com/two")
browser.close()
# GOOD - Reuse browser context
@pytest.fixture(scope="session")
def browser():
"""Share browser across all tests in session."""
pw = sync_playwright().start()
browser = pw.chromium.launch()
yield browser
browser.close()
pw.stop()
@pytest.fixture
def page(browser):
"""Create fresh context per test for isolation."""
context = browser.new_context()
page = context.new_page()
yield page
context.close()# BAD - Sequential scraping
def scrape_all(urls: list) -> list:
results = []
for url in urls:
page.goto(url)
results.append(page.content())
return results # Very slow for many URLs
# GOOD - Parallel with multiple contexts
def scrape_all_parallel(urls: list, browser, max_workers: int = 4) -> list:
"""Scrape URLs in parallel using multiple contexts."""
from concurrent.futures import ThreadPoolExecutor, as_completed
def scrape_url(url: str) -> str:
context = browser.new_context()
page = context.new_page()
try:
page.goto(url, wait_until='domcontentloaded')
return page.content()
finally:
context.close()
with ThreadPoolExecutor(max_workers=max_workers) as executor:
futures = {executor.submit(scrape_url, url): url for url in urls}
return [future.result() for future in as_completed(futures)]# BAD - Load all resources
page.goto("https://example.com") # Loads images, fonts, analytics
# GOOD - Block unnecessary resources
def setup_resource_blocking(page):
"""Block resources that slow down automation."""
page.route("**/*", lambda route: (
route.abort() if route.request.resource_type in [
"image", "media", "font", "stylesheet"
] else route.continue_()
))
# Usage
setup_resource_blocking(page)
page.goto("https://example.com") # 2-3x faster# BAD - Allow all tracking requests
page.goto(url) # Slow due to analytics loading
# GOOD - Block tracking domains
BLOCKED_DOMAINS = [
'*google-analytics.com*',
'*googletagmanager.com*',
'*facebook.com/tr*',
'*doubleclick.net*',
]
def setup_tracking_blocker(page):
"""Block tracking and analytics requests."""
for pattern in BLOCKED_DOMAINS:
page.route(pattern, lambda route: route.abort())
# Apply before navigation
setup_tracking_blocker(page)
page.goto(url) # Faster, no tracking overhead# BAD - Slow selectors
page.locator("//div[@class='container']//span[contains(text(), 'Submit')]").click()
page.wait_for_selector(".dynamic-content", timeout=30000)
# GOOD - Fast, specific selectors
page.locator("[data-testid='submit-button']").click() # Direct attribute
page.locator("#unique-id").click() # ID is fastest
# GOOD - Use role selectors for accessibility
page.get_by_role("button", name="Submit").click()
page.get_by_label("Email").fill("test@example.com")
# GOOD - Combine selectors for specificity without XPath
page.locator("form.login >> button[type='submit']").click()When automating browsers:
Every browser operation MUST:
Chrome DevTools Protocol (CDP):
WebDriver/Selenium:
Modern Frameworks:
| Risk Area | Mitigation | Priority |
|---|---|---|
| Credential theft | Domain allowlists | CRITICAL |
| Phishing | URL validation | CRITICAL |
| Data exfiltration | Output filtering | HIGH |
| Session hijacking | Isolated profiles | HIGH |
from playwright.sync_api import sync_playwright
import logging
import re
from urllib.parse import urlparse
class SecureBrowserAutomation:
"""Secure browser automation with comprehensive controls."""
BLOCKED_DOMAINS = {
'chase.com', 'bankofamerica.com', 'wellsfargo.com',
'accounts.google.com', 'login.microsoft.com',
'paypal.com', 'venmo.com', 'stripe.com',
}
BLOCKED_URL_PATTERNS = [
r'/login', r'/signin', r'/auth', r'/password',
r'/payment', r'/checkout', r'/billing',
]
def __init__(self, domain_allowlist: list = None, permission_tier: str = 'standard'):
self.domain_allowlist = domain_allowlist
self.permission_tier = permission_tier
self.logger = logging.getLogger('browser.security')
self.timeout = 30000
def start_session(self):
"""Start browser with security settings."""
self.playwright = sync_playwright().start()
self.browser = self.playwright.chromium.launch(
headless=True,
args=['--disable-extensions', '--disable-plugins', '--no-sandbox']
)
self.context = self.browser.new_context(ignore_https_errors=False)
self.context.set_default_timeout(self.timeout)
self.page = self.context.new_page()
def navigate(self, url: str):
"""Navigate with URL validation."""
if not self._validate_url(url):
raise SecurityError(f"URL blocked: {url}")
self._audit_log('navigate', url)
self.page.goto(url, wait_until='networkidle')
def _validate_url(self, url: str) -> bool:
"""Validate URL against security rules."""
parsed = urlparse(url)
domain = parsed.netloc.lower().removeprefix('www.')
if any(domain == d or domain.endswith('.' + d) for d in self.BLOCKED_DOMAINS):
return False
if self.domain_allowlist:
if not any(domain == d or domain.endswith('.' + d) for d in self.domain_allowlist):
return False
return not any(re.search(p, url, re.I) for p in self.BLOCKED_URL_PATTERNS)
def close(self):
"""Clean up browser session."""
if hasattr(self, 'context'):
self.context.clear_cookies()
self.context.close()
if hasattr(self, 'browser'):
self.browser.close()
if hasattr(self, 'playwright'):
self.playwright.stop()import time
class BrowserRateLimiter:
"""Rate limit browser operations."""
def __init__(self, requests_per_minute: int = 60):
self.requests_per_minute = requests_per_minute
self.request_times = []
def check_request(self):
"""Check if request is allowed."""
cutoff = time.time() - 60
self.request_times = [t for t in self.request_times if t > cutoff]
if len(self.request_times) >= self.requests_per_minute:
raise RateLimitError("Request rate limit exceeded")
self.request_times.append(time.time())| Vulnerability | CWE | Severity | Mitigation |
|---|---|---|---|
| XSS via Automation | CWE-79 | HIGH | Sanitize injected scripts |
| Credential Harvesting | CWE-522 | CRITICAL | Block password field access |
| Session Hijacking | CWE-384 | HIGH | Isolated profiles, session clearing |
| Phishing Automation | CWE-601 | CRITICAL | Domain allowlists, URL validation |
# Never: Fill Password Fields
# BAD
page.fill('input[type="password"]', password)
# GOOD
if element.get_attribute('type') == 'password':
raise SecurityError("Cannot fill password fields")
# Never: Access Banking Sites
# BAD
page.goto(user_url)
# GOOD
if not validate_url(user_url):
raise SecurityError("URL blocked")
page.goto(user_url)pytest tests/test_browser_automation.pypytest -k securityYour goal is to create browser automation that is:
Implementation Order:
references/secure-session-full.md - Complete SecureBrowserAutomation classreferences/security-examples.md - Additional security patternsreferences/threat-model.md - Full threat analysis1086ef2
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