Censys – External Attack Surface Management & Internet Scanning

Overview

Censys specializes in external attack surface management (EASM) and internet-wide scanning, providing tools for organizations to identify, monitor, and secure their internet-facing assets. The platform helps security teams gain visibility into their digital footprint, including assets they may not be aware of, by continuously scanning the public internet. This process involves collecting data on hosts, services, and certificates to build a comprehensive view of an organization's exposure.

The core products offered are Censys Attack Surface Management and Censys Search. Censys Attack Surface Management is designed for continuous discovery and monitoring of an organization's external assets, identifying misconfigurations, vulnerabilities, and shadow IT. This proactive approach aims to reduce the attack surface by providing actionable insights into potential weaknesses. Censys Search, on the other hand, offers a searchable database of internet scan data, allowing users to query and analyze information about devices, services, and certificates observed across the internet. This capability supports threat intelligence, vulnerability research, and incident response by enabling security professionals to investigate global internet trends and specific exposures.

Censys is primarily used by security operations teams, threat intelligence analysts, and vulnerability researchers. It helps these professionals understand their organization's internet presence from an attacker's perspective, identifying potential entry points and exposed data. The platform's data can be used for various security activities, including proactive vulnerability management, compliance auditing, and monitoring for newly emerging threats. For instance, security teams can use Censys to track the deployment of specific software versions across their infrastructure or to detect unauthorized services running on their networks.

The API provides programmatic access to Censys's data and capabilities, enabling integration with existing security workflows and automation of asset discovery and monitoring tasks. Developers can use the Python and Go SDKs to interact with the API, simplifying data retrieval and analysis. This allows for custom reports, automated alerts, and integration with SIEM (Security Information and Event Management) or SOAR (Security Orchestration, Automation, and Response) platforms. The platform's ability to provide a real-time view of an organization's external attack surface is crucial for maintaining a strong security posture in dynamic cloud environments and distributed infrastructures.

Key features

• External Asset Discovery: Automatically identifies internet-facing assets belonging to an organization, including domains, IP addresses, certificates, and cloud resources, often uncovering previously unknown assets.
• Continuous Monitoring: Provides ongoing surveillance of the external attack surface to detect changes, new exposures, and emerging vulnerabilities in real time.
• Vulnerability Detection: Identifies common vulnerabilities and misconfigurations on exposed services, such as outdated software versions, weak encryption, and open ports.
• Threat Intelligence Integration: Allows users to query a vast dataset of internet scan results for threat hunting, research, and understanding global exposure trends.
• Attack Surface Scorecard: Offers a consolidated view of an organization's security posture, highlighting critical risks and providing recommendations for remediation.
• API Access and SDKs: Provides a RESTful API and official SDKs for Python and Go, enabling programmatic interaction and integration with other security tools and workflows (Censys API documentation).
• Compliance Reporting: Assists with compliance efforts by providing visibility into external assets and their configurations, supporting frameworks like SOC 2 Type II, GDPR, and CCPA.

Pricing

Censys offers a free community edition and tiered paid plans. The pricing structure is based on the scope of the attack surface and required features, with enterprise options available for larger deployments.

For detailed pricing information and to request a custom quote, refer to the Censys pricing page.

Common integrations

• Security Information and Event Management (SIEM) Systems: Integrate Censys data to enrich security logs and provide context for alerts, enhancing incident detection and response workflows.
• Vulnerability Management Platforms: Automatically feed discovered assets and vulnerabilities into existing vulnerability management systems for consolidated tracking and remediation.
• Cloud Security Posture Management (CSPM) Tools: Complement CSPM solutions by providing external visibility into cloud assets and services exposed to the internet.
• Threat Intelligence Platforms (TIPs): Incorporate Censys scan data into TIPs to enhance threat analysis and inform defensive strategies.
• Security Orchestration, Automation, and Response (SOAR) Platforms: Automate responses to newly discovered exposures or vulnerabilities by triggering playbooks based on Censys alerts.

Alternatives

• Shodan: A search engine for internet-connected devices, providing similar capabilities for discovering exposed services and devices.
• Bitsight: Offers security ratings and continuous monitoring of an organization's security performance, including attack surface insights.
• RiskIQ (Microsoft Defender External Attack Surface Management): Provides discovery, inventory, and monitoring of external assets, similar to Censys's EASM offerings.

Getting started

To begin using the Censys API, you will need an API ID and Secret. These credentials can be obtained from your Censys account. The following Python example demonstrates how to perform a basic search using the Censys Python SDK to find hosts with a specific service.

import censys.asm

# Replace with your actual API ID and Secret
CENSYS_API_ID = "YOUR_CENSYS_API_ID"
CENSYS_API_SECRET = "YOUR_CENSYS_API_SECRET"

# Initialize the ASM client
# For Censys Search, you would use censys.search.CensysSearchAPI
client = censys.asm.AsmClient(api_key=CENSYS_API_SECRET, api_id=CENSYS_API_ID)

try:
    # Example: List assets (e.g., hosts, domains)
    # This is a simplified example; actual asset queries can be more complex
    # For detailed search queries, refer to the Censys Search API documentation
    # at https://docs.censys.com/api/v2/search

    # To search for hosts with specific criteria using the Search API (not ASM client):
    # from censys.search import CensysSearchAPI
    # search_client = CensysSearchAPI(api_key=CENSYS_API_SECRET, api_id=CENSYS_API_ID)
    # query = "service.service_name:HTTP and tags:" + "web_server"
    # for page in search_client.v2.hosts.search(query=query):
    #     for host in page["result"]["hits"]:
    #         print(f"Found host: {host['ip']} with services: {host['services'][0]['service_name']}")

    print("Censys API client initialized. Refer to the documentation for specific queries.")
    print("For example, to list assets in ASM, you might use client.assets.list_assets()")
    print("Or for internet-wide search, use the Censys Search API client.")

except Exception as e:
    print(f"An error occurred: {e}")
    print("Please ensure your API ID and Secret are correct and you have network connectivity.")

This Python snippet initializes a Censys client. For actual data retrieval and attack surface management, developers should consult the Censys API documentation for specific endpoints and query parameters. The documentation provides examples for various use cases, including asset discovery, vulnerability analysis, and data export.