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/learning/openvas-greenbone-credentialed-vs-unauthenticated-scans :: module-8

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OpenVAS / Greenbone Scanning: Credentialed vs Unauthenticated Scans

Understand what vulnerability scanners can and cannot tell you, and why credentialed scans are often dramatically more useful for remediation planning than unauthenticated scans alone.

Many teams treat scanner output as ground truth without understanding coverage limitations. Knowing the difference between credentialed and unauthenticated scanning improves accuracy, prioritization, and trust with operations teams.

learning-objectives

$Explain the purpose and limitations of unauthenticated scans.
$Explain how credentialed scans improve software/configuration visibility.
$Interpret scanner findings in the context of asset role and compensating controls.
$Build a basic scan schedule and exception process.

example-dataflow-and-observation-paths

Use these example dataflows to trace how activity moves through systems and where a defender can observe evidence. This is how learners move from memorizing terms to thinking like investigators.

$Unauthenticated scan reveals exposed services -> credentialed scan checks installed software/config -> findings triaged by criticality -> tickets assigned -> remediation validated with re-scan and manual checks.
$Scanner finding -> analyst validation on host -> owner notified with evidence -> patch/config change -> follow-up scan confirms closure.
$Vulnerability management pipeline: scan scheduling -> result review -> prioritization -> remediation -> exception handling -> metrics reporting.

baseline-normal-before-debugging

$Credentialed scans show deeper package/config visibility than unauthenticated scans.
$Findings can be grouped by owner and asset criticality for remediation planning.
$Re-scan results reflect closures after patching or config changes are applied.

Expert tip: Baseline normal behavior before writing detections or escalating anomalies. Most tuning and triage errors come from skipping this step.

concept-breakdown-and-mastery

1. What Scanners Actually Do

$ core idea: Vulnerability scanners identify exposed services, inspect banners, test protocol behavior, and (in credentialed mode) query the host for installed packages, versions, and configurations. They estimate risk, but they do not replace validation and context.

$ defender angle: Scanner findings can include false positives, duplicate findings, and findings that are technically true but operationally low risk due to segmentation or disabled code paths. Analysts must interpret results with architecture knowledge.

$ prove understanding: Explain the purpose and limitations of unauthenticated scans.

2. Unauthenticated vs Credentialed Scanning

$ core idea: Unauthenticated scans show you what an external or network-adjacent attacker might directly observe, which is valuable for exposure discovery. However, they often miss internal package-level vulnerabilities or produce less precise version information.

$ defender angle: Credentialed scans use approved credentials to inspect installed software and configurations from the inside. This improves coverage and remediation accuracy, especially on servers where patch state cannot be inferred reliably from banners.

$ prove understanding: Explain how credentialed scans improve software/configuration visibility.

3. Operationalizing Scan Results

$ core idea: Group findings by asset criticality, internet exposure, exploitability, and ownership. Raw scanner severity alone is not enough for queue prioritization.

$ defender angle: Define remediation states clearly (new, validated, in progress, exception, mitigated, remediated, risk accepted). Ambiguous statuses create reporting confusion and hide backlog growth.

$ prove understanding: Interpret scanner findings in the context of asset role and compensating controls.

deep-dive-notes-expanded

Work through the sections in order. For each section, learn the theory, identify normal behavior, identify failure patterns, then validate with packet/log/CLI evidence.

1. What Scanners Actually Do

Vulnerability scanners identify exposed services, inspect banners, test protocol behavior, and (in credentialed mode) query the host for installed packages, versions, and configurations. They estimate risk, but they do not replace validation and context.

Scanner findings can include false positives, duplicate findings, and findings that are technically true but operationally low risk due to segmentation or disabled code paths. Analysts must interpret results with architecture knowledge.

Use scans as a recurring measurement practice, not a one-off compliance event.

Normal Behavior

Credentialed scans show deeper package/config visibility than unauthenticated scans.

Failure / Abuse Pattern

Teams rely on unauthenticated scans only and miss package-level exposure details.

Evidence To Collect

Explain the purpose and limitations of unauthenticated scans.

2. Unauthenticated vs Credentialed Scanning

Unauthenticated scans show you what an external or network-adjacent attacker might directly observe, which is valuable for exposure discovery. However, they often miss internal package-level vulnerabilities or produce less precise version information.

Credentialed scans use approved credentials to inspect installed software and configurations from the inside. This improves coverage and remediation accuracy, especially on servers where patch state cannot be inferred reliably from banners.

A strong program usually combines both approaches: unauthenticated scans for exposure view and credentialed scans for maintenance and remediation planning.

Normal Behavior

Findings can be grouped by owner and asset criticality for remediation planning.

Failure / Abuse Pattern

Credentialed scan findings are trusted blindly without validating unusual results.

Evidence To Collect

Explain how credentialed scans improve software/configuration visibility.

3. Operationalizing Scan Results

Group findings by asset criticality, internet exposure, exploitability, and ownership. Raw scanner severity alone is not enough for queue prioritization.

Define remediation states clearly (new, validated, in progress, exception, mitigated, remediated, risk accepted). Ambiguous statuses create reporting confusion and hide backlog growth.

Re-scan after remediation and verify closure. If findings persist, determine whether the issue is patching failure, detection mismatch, or a configuration path still exposing the weakness.

Normal Behavior

Re-scan results reflect closures after patching or config changes are applied.

Failure / Abuse Pattern

Scan reports accumulate without owner assignment or remediation validation.

Evidence To Collect

Interpret scanner findings in the context of asset role and compensating controls.

terminal-walkthroughs-with-example-output

These walkthroughs show representative commands plus example output so learners know what success and useful evidence look like. Treat the output as a pattern guide, not a fixed transcript.

Greenbone / OpenVAS Workflow (Conceptual CLI)

Beginner

Command

sudo systemctl status ospd-openvas || true

Example Output

● service.service - Active: active (running)
Tasks: ... Memory: ...

$ why this matters: Use this step to validate greenbone / openvas workflow (conceptual cli) before moving on to more advanced commands in the same block. Focus on interpreting the output, not just running the command.

Scan Validation Checklist Commands

Intermediate

Command

ssh user@target 'uname -a && cat /etc/os-release'

Example Output

# command executed in lab
# review output for expected fields, errors, and anomalies

$ why this matters: Use this step to validate scan validation checklist commands before moving on to more advanced commands in the same block. Focus on interpreting the output, not just running the command.

Evidence Export Prep

Advanced

Command

mkdir -p reports/vuln-scans

Example Output

# command executed in lab
# review output for expected fields, errors, and anomalies

$ why this matters: Use this step to validate evidence export prep before moving on to more advanced commands in the same block. Focus on interpreting the output, not just running the command.

cli-labs-and-workflow

Run these commands only in environments you own or are explicitly authorized to test. Use a lab VM, sandbox network, or approved internal test segment for practice.

Greenbone / OpenVAS Workflow (Conceptual CLI)

Beginner

sudo systemctl status ospd-openvas || true
sudo systemctl status gvmd || true
sudo systemctl status gsad || true

Run in a lab or authorized environment. Record what fields change when you alter the test conditions.

Scan Validation Checklist Commands

Intermediate

ssh user@target 'uname -a && cat /etc/os-release'
ssh user@target 'dpkg -l | head'   # Debian/Ubuntu example
ssh user@target 'rpm -qa | head'   # RHEL-family example

Run in a lab or authorized environment. Record what fields change when you alter the test conditions.

Evidence Export Prep

Advanced

mkdir -p reports/vuln-scans
cp scan-summary.csv reports/vuln-scans/  # example exported report

Run in a lab or authorized environment. Record what fields change when you alter the test conditions.

expert-mode-study-loop

$Explain the concept in plain language without reading notes.
$Show how to validate the concept with logs, packets, or commands.
$Name at least one common failure mode and how to detect it.
$Document what 'normal' looks like before testing edge cases.

Progress marker: You are ready to move on when you can explain the topic, run the commands, and interpret the output without guessing.

knowledge-check-and-answer-key

Try answering these from memory before looking at the hints. These questions are designed to test understanding of concepts, dataflow, and evidence collection.

1. What Scanners Actually Do

Questions

?How would you explain "What Scanners Actually Do" to a new defender in plain language?
?What does normal behavior look like for what scanners actually do in your lab or environment?
?Which logs, packets, or commands would you use to validate what scanners actually do?
?What failure mode or attacker abuse pattern matters most for what scanners actually do?

Show answer key / hints

Answer Key / Hints

#Explain the purpose and limitations of unauthenticated scans.
#Credentialed scans show deeper package/config visibility than unauthenticated scans.
#sudo systemctl status ospd-openvas || true
#Teams rely on unauthenticated scans only and miss package-level exposure details.

2. Unauthenticated vs Credentialed Scanning

Questions

?How would you explain "Unauthenticated vs Credentialed Scanning" to a new defender in plain language?
?What does normal behavior look like for unauthenticated vs credentialed scanning in your lab or environment?
?Which logs, packets, or commands would you use to validate unauthenticated vs credentialed scanning?
?What failure mode or attacker abuse pattern matters most for unauthenticated vs credentialed scanning?

Show answer key / hints

Answer Key / Hints

#Explain how credentialed scans improve software/configuration visibility.
#Findings can be grouped by owner and asset criticality for remediation planning.
#ssh user@target 'uname -a && cat /etc/os-release'
#Credentialed scan findings are trusted blindly without validating unusual results.

3. Operationalizing Scan Results

Questions

?How would you explain "Operationalizing Scan Results" to a new defender in plain language?
?What does normal behavior look like for operationalizing scan results in your lab or environment?
?Which logs, packets, or commands would you use to validate operationalizing scan results?
?What failure mode or attacker abuse pattern matters most for operationalizing scan results?

Show answer key / hints

Answer Key / Hints

#Interpret scanner findings in the context of asset role and compensating controls.
#Re-scan results reflect closures after patching or config changes are applied.
#mkdir -p reports/vuln-scans
#Scan reports accumulate without owner assignment or remediation validation.

lab-answer-key-expected-findings

Use this as a baseline answer key for labs and walkthroughs. Replace these with environment-specific observations as you practice in real or simulated networks.

Expected Normal Findings

+Credentialed scans show deeper package/config visibility than unauthenticated scans.
+Findings can be grouped by owner and asset criticality for remediation planning.
+Re-scan results reflect closures after patching or config changes are applied.

Expected Failure / Anomaly Clues

!Teams rely on unauthenticated scans only and miss package-level exposure details.
!Credentialed scan findings are trusted blindly without validating unusual results.
!Scan reports accumulate without owner assignment or remediation validation.

hands-on-labs

$Run an unauthenticated scan against a lab host and compare findings with a credentialed scan of the same system.
$Classify findings by exposure and business criticality, not only scanner severity.
$Create a remediation ticket template that includes evidence, owner, due date, and validation steps.

common-pitfalls

$Assuming a “clean scan” means a system is secure.
$Running credentialed scans with overly privileged shared accounts and poor key handling.
$No process for validating false positives before escalating remediation.

tools-and-references

completion-outputs

# A scan strategy document (external vs internal vs credentialed)
# A finding triage matrix for vuln operations
# A remediation validation checklist

<- previous page Nmap Scanning Strategy and Safe Validation Workflows -> next page Exploit-Informed Remediation and Asset Criticality Tagging

learning-path-position

Vulnerability & Exposure / Weeks 7-8 · Module 8 of 12