Vulnerability Assessment with Nessus
A controlled vulnerability-assessment workflow for an authorized lab: scope the assets, configure a safe scan policy, triage findings, validate high-value results, and document remediation rather than treating scanner output as an automatic incident verdict.
SCOPE & SAFETY
The assessment starts with an explicit target list and permission boundary. Example assets use RFC1918-style lab addressing. Discovery, credentials, scan intensity, maintenance windows, and exclusions are recorded before the scanner is started.
SCAN DESIGN
The scan is configured around the purpose of the assessment: host discovery, common service exposure, software/version checks, and authenticated checks where credentials are available. Rate limits and maintenance windows reduce unnecessary load on fragile systems.
TRIAGE & VALIDATION
Findings are grouped by severity, exploitability, affected asset, and business impact. A critical-looking plugin result is not accepted blindly: version evidence, package state, vendor advisories, and compensating controls are checked before remediation is prioritized.
$ ping -c 2 192.168.56.20 64 bytes from 192.168.56.20: icmp_seq=1 ttl=64 time=0.4 ms 64 bytes from 192.168.56.20: icmp_seq=2 ttl=64 time=0.3 ms $ nmap -sV --version-light 192.168.56.20 22/tcp open ssh OpenSSH <lab-version> 80/tcp open http <lab-service>
$ ssh labadmin@192.168.56.20 'uname -a; dpkg -l | grep -E "openssl|openssh"' Linux lab-host ... <package evidence> $ echo 'Nessus finding: VERIFY AGAINST PACKAGE + ADVISORY' Nessus finding: VERIFY AGAINST PACKAGE + ADVISORY
REMEDIATION STORY
A strong report connects finding → evidence → fix → verification. Typical remediation includes patching the affected package, removing an unnecessary service, tightening configuration, or upgrading a supported release. The same check is repeated after the change.
LESSONS LEARNED
The scanner is a decision-support tool. The quality of the final report depends on scope control, credential coverage, false-positive review, and clear remediation ownership.