A passive vulnerability scan is a type of security scan in which the scanner sends no unusual requests to the server. It behaves like a normal visitor browsing the website and observing publicly exposed information.
Passive scanning is often supported as part of a modern vulnerability scanner, making it ideal for early-stage risk identification without impacting availability.
Let’s review the benefits of a passive vulnerability scan.
Pick Low Hanging Fruits
Browsing the website is the first thing hackers and security experts do when evaluating a website’s security. This process is commonly referred to as a passive scan.
Many issues can be identified simply by inspecting the source code of web pages. Problems such as Vulnerable WordPress Version, Application Errors, and Password Over Unencrypted Channel are typical examples.
Intercepting requests and responses between the browser and the server can also reveal weaknesses. For instance, misconfigured cookies and security headers are frequently detected during a web vulnerability scanner passive analysis.
Less Impact
Passive scans, compared to active scans, pose significantly less risk to the availability of a web application. Because no unexpected requests are sent, the server processes the scan like any normal user interaction.
⛔ In passive scans, all URLs are visited. If there are links that trigger destructive actions (such as deleting accounts or data), passive scans can still introduce risk.
Bypass Web Application Firewalls
Websites often rely on Web Application Firewalls (WAFs) to block malicious traffic in production environments. Passive scans rarely trigger WAF rules, allowing the assessment to continue without disruption.
This makes passive scanning especially useful when running security checks against live environments protected by WAFs and monitoring solutions.
No Schedule Required
Active vulnerability scans can place heavy load on applications and are typically scheduled during low-traffic windows. Passive scans, on the other hand, can be executed at any time, mirroring normal visitor behavior.
They are well suited for continuous monitoring when used alongside automated pentest automation tools.
Fast Security Scan
Since passive scans involve fewer requests, they complete quickly. Reduced interaction with security controls such as WAFs also minimizes throttling and scanning delays.
Passive scanning is often the fastest way to gain visibility into common misconfigurations and information disclosure risks.
How To Perform A Passive Scan?
You can use SmartScanner — a smart web vulnerability scanner — to perform passive scans.
Download SmartScanner and install it.
Open SmartScanner and enter your website address. Click the gear icon in the input field, select the Passive test profile, then start the scan. Once completed, review the identified issues.
Is Passive Scan Enough?
No. Passive scans alone do not provide full security coverage.
For comprehensive protection, passive scanning should be combined with active testing and broader assessments such as OWASP Top 10 scanning. Passive scans are best used for quick evaluations or as part of a continuous security strategy.
