Vulnerability scanning should not be confused with penetration testing. A scanner is an automated tool that looks for already known vulnerabilities and produces a report. A pentester looks for unknown, creative flaws. The two do not replace each other — they complement each other. A good security strategy combines weekly automated scans with a manual pentest twice a year.
Network and web application scanners
Vulnerability scanners split into two big categories. Network scanners check the whole network for open ports, outdated versions and misconfigured services. Web application scanners work directly with sites, looking for SQL injection, XSS, CSRF and other OWASP class issues. In a corporate environment both types are needed because they cover different layers.
Nessus — the industry standard
The Nessus product from Tenable is the most popular vulnerability scanner. It contains over 100 thousand plugins, updates almost daily and is fully synchronized with the MITRE CVE database. A Nessus Professional license costs around 3990 dollars per year — a noticeable expense for small businesses. Nessus Essentials is a free version, but it covers only 16 IP addresses.
Acunetix and Invicti
In the web application scanning space, Acunetix and Invicti (formerly Netsparker) are the leaders. Acunetix uses its DeepScan technology to correctly analyze even JavaScript-heavy single-page apps. Invicti uses proof-based scanning — every finding is confirmed in practice, minimizing false positives. Both tools start at around 6 thousand dollars per year.
OpenVAS — the open source alternative
For teams with limited budgets, OpenVAS (now Greenbone Vulnerability Manager) is the best choice. It is fully open source, free, and functionally competitive with Nessus. It includes more than 80 thousand tests and updates daily. Sayt.uz uses OpenVAS in its internal audit pipelines.
Fighting false positives
The biggest problem with any automated scanner is false positives — reports of issues that do not actually exist. A junior security engineer can drown in thousands of false alarms. The fix is manual verification, baseline tuning and gradual adaptation to the environment. Sayt.uz filters reports before they reach the customer, showing only real findings.
Sayt.uz in practice
Sayt.uz runs a weekly automated vulnerability scan for every customer site, and critical findings appear in the cabinet immediately. Premium plans include daily scans and a deeper audit based on Nessus Professional. The scan is free on Premium, and as a standalone service starts at 180 thousand soum per month. As of 2026, our scanners have detected 12,480 vulnerabilities at customer sites, with 92 percent closed within 30 days.