External Attack Surface Monitoring (EASM)
Continuously discover, monitor, and manage your external attack surface to identify exposed assets and reduce cyber risk before attackers exploit them.
The Challenge
Shadow IT & Unknown Assets
Uncontrolled acquisition of IT services exposes you to hidden external risks
Lack of External Visibility
Limited understanding of what attackers can see from outside your network perimeter
Point-in-Time Scanning Gaps
One-off security assessments miss emerging exposures between scans
Asset Attribution Challenges
Difficulty connecting discovered assets back to your organisation with confidence
What is External Attack Surface Monitoring (EASM)?
External Attack Surface Management (EASM) is the broader practice this sits within: continuously discovering, monitoring and understanding the internet-facing assets an organisation owns - websites, subdomains, cloud services, APIs and infrastructure - including ones IT teams may not know exist. Claranet's Attack Surface Monitoring service delivers the discovery and monitoring core of EASM: finding exposed assets, validating who owns them, and reporting the risks they introduce, so your security team can act before attackers find them first.
Attack Surface Monitoring is a managed service that delivers continuous visibility of your externally exposed Internet-facing assets. Our proprietary platform aggregates and correlates data from multiple open-source and commercial sources to provide a comprehensive view of your attack surface.
Each month, you receive an analyst-reviewed PDF report via a secure portal, detailing newly identified assets, exposures, misconfigurations, and emerging patterns that could impact your security posture.
Key benefits
- Continuous discovery throughout the month (non-invasive, non-disruptive)
- Analyst-reviewed monthly reports with actionable insights
- Proprietary platform correlating 9+ data sources
- Attribution confidence scoring for accurate asset ownership
- Optional quarterly business reviews for trend analysis
- Integrates seamlessly with Claranet's Continuous Security Testing service
Credentials
Service Components
ASM Platform
Proprietary Claranet platform aggregating and correlating externally observable asset data
Passive Intelligence
Passive DNS, TLS, WHOIS, and BGP data for domain relationships and hosting changes
Active Enumeration
Banner grabbing, service enumeration, and lightweight active checks on IPs
Attribution Scoring
Weighted scoring using passive and active signals to validate asset ownership
Monthly Reporting
Comprehensive PDF reports with analyst insights on patterns and risk indicators
Quarterly Reviews
Optional business review meetings for trend analysis and consolidated insights (chargeable)
Multi-Source Data Aggregation
Integrates WhoisXML, Shodan, Censys, FOFA, and open-source tools
Cloud Integration Support
Optional API integrations with Microsoft Azure and AWS for expanded visibility
How EASM complements penetration testing and vulnerability scanning?
Attack Surface Monitoring and penetration testing answer different questions. Monitoring continuously tells you what is exposed on your internet-facing estate and how that exposure changes month to month. Penetration testing - delivered through Claranet's CREST-accredited testing team - goes further, expertly probing those assets to find exploitable weaknesses. Used together, monitoring keeps your testing scope current, so nothing newly exposed goes untested, and Continuous Security Testing can validate and re-test as assets change. This differs from a one-off vulnerability scan, which only reflects a single point in time.
EASM and Managed Detection and Response (MDR)
Attack Surface Monitoring covers your external perimeter - what's visible and exposed from outside your organisation. Managed Detection and Response covers your internal estate - detecting and responding to active threats once inside. Together they give you visibility across both the exposure stage and the active-threat stage of an attack.
Industry-Leading Accreditations
See what's exposed on your external attack surface
Get a clear, continuously updated view of your internet-facing assets and the risks they carry - reviewed monthly by CREST-accredited analysts, and ready to feed directly into your testing and remediation programme.
Explore our cybersecurity services
Speak to an attack surface monitoring specialist
Or call us on 0330 390 0507
Frequently asked questions
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External Attack Surface Management (EASM) is the practice of continuously discovering, monitoring and understanding the internet-facing assets an organisation owns - websites, subdomains, cloud services, APIs and infrastructure - including ones IT teams may not know exist. Claranet's Attack Surface Monitoring service delivers the discovery and monitoring core of EASM: finding exposed assets, validating who owns them, and reporting the risks they introduce, so your security team can act before attackers find them first.
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Attack Surface Monitoring continuously tells you what is exposed on your internet-facing estate and how that exposure changes month to month. A penetration test - delivered through Claranet's CREST-accredited testing team - goes further, expertly probing those assets to find exploitable weaknesses. Used together, monitoring keeps your testing scope current, so nothing newly exposed goes untested, and Continuous Security Testing can validate and re-test as assets change. This differs from a one-off vulnerability scan, which only reflects a single point in time.
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Continuously — new assets and exposures are discovered throughout the month, with a full analyst-reviewed report delivered every month (12 discovery cycles a year)." - directly supported by the existing "12 Monthly Discovery Cycles" credential.
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Our platform aggregates and correlates data from more than nine sources, including passive DNS, TLS, WHOIS and BGP data, alongside tools such as Shodan, Censys, FOFA and WhoisXML, combined with lightweight active checks like banner grabbing and service enumeration