Sekost is a cybersecurity diagnostic tool designed for small and medium-sized enterprises (SMEs) to assess their external attack surface. The platform performs automated scanning of internet-facing assets using only a domain name or IP address, without requiring access to internal systems. The tool maps exposed digital assets including websites, IP addresses, servers, databases, ERP systems, CRM platforms, and administrative portals. It identifies exploitable vulnerabilities visible to potential attackers and provides risk-prioritized findings. Sekost offers three service tiers: Flash Cyber provides a rapid assessment in postcard format, Diagnostic Cyber delivers a comprehensive audit with maturity scoring and prioritized recommendations, and Check-up Cyber enables recurring scans with historical tracking. Reports are designed to be actionable for non-technical audiences, focusing on the 20% of actions that address 80% of risk exposure. The platform is hosted in France and developed by ethical hackers with bug bounty and enterprise audit experience. The solution is distributed through IT service providers, accountants, and other trusted partners who integrate it into their service offerings.