performing-authenticated-scan-with-openvas - SKILL.md Agent Skill

name: performing-authenticated-scan-with-openvas description: Configure and execute authenticated vulnerability scans using OpenVAS/Greenbone Vulnerability Management with SSH and SMB credentials for comprehensive host-level assessment. domain: cybersecurity subdomain: vulnerability-management tags:

openvas
gvm
authenticated-scan
vulnerability-scanning
greenbone
network-security
credentialed-scan version: '1.0' author: mahipal license: Apache-2.0 nist_csf:
ID.RA-01
ID.RA-02
ID.IM-02
ID.RA-06

Performing Authenticated Scan with OpenVAS

Overview

OpenVAS (Open Vulnerability Assessment Scanner) is the scanner component of the Greenbone Vulnerability Management (GVM) framework. Authenticated scans use valid credentials (SSH for Linux, SMB for Windows, ESXi for VMware) to log into target systems, enabling detection of local vulnerabilities, missing patches, and misconfigurations that unauthenticated scans cannot identify. Authenticated scans typically find 10-50x more vulnerabilities than unauthenticated scans.

When to Use

When conducting security assessments that involve performing authenticated scan with openvas
When following incident response procedures for related security events
When performing scheduled security testing or auditing activities
When validating security controls through hands-on testing

Prerequisites

GVM 22.x+ installed (gvmd, openvas-scanner, gsad, ospd-openvas)
PostgreSQL database configured for gvmd
Redis configured for openvas-scanner
NVT feed synchronized (greenbone-nvt-sync or greenbone-feed-sync)
SSH credentials for Linux targets or SMB credentials for Windows targets
Network access to target hosts on scan ports

Installation

# Install required dependencies
sudo apt-get update && sudo apt-get install -y <tool-name>

Install GVM on Kali Linux / Debian

# Install GVM package
sudo apt update && sudo apt install -y gvm

# Run initial setup (creates admin account, syncs feeds)
sudo gvm-setup

# Check installation status
sudo gvm-check-setup

# Start all GVM services
sudo gvm-start

# Access Greenbone Security Assistant at https://127.0.0.1:9392

Install via Docker (Recommended for Production)

# Pull Greenbone Community Edition containers
docker pull greenbone/gvm:stable

# Run with docker-compose
curl -fsSL https://greenbone.github.io/docs/latest/_static/docker-compose-22.4.yml \
  -o docker-compose.yml

# Start the stack
docker compose -f docker-compose.yml -p greenbone-community-edition up -d

# Wait for feed sync (initial sync takes 15-30 minutes)
docker compose -f docker-compose.yml -p greenbone-community-edition \
  logs -f gvmd 2>&1 | grep -i "feed"

Configuring Credentials

This section covers configuring credentials for performing authenticated scan with openvas.

Ensure all prerequisites are met before proceeding
Follow the documented workflow steps in sequence
Record results and any anomalies encountered during this phase

SSH Credentials for Linux Targets

# Using gvm-cli to create SSH credential with key-based auth
gvm-cli socket --socketpath /run/gvmd/gvmd.sock --gmp-username admin --gmp-password <password> --xml \
  '<create_credential>
    <name>Linux SSH Key</name>
    <type>usk</type>
    <login>scan_user</login>
    <key>
      <private><![CDATA['"$(cat /home/scan_user/.ssh/id_rsa)"']]></private>
      <phrase>key_passphrase</phrase>
    </key>
  </create_credential>'

# SSH credential with password authentication
gvm-cli socket --socketpath /run/gvmd/gvmd.sock --gmp-username admin --gmp-password <password> --xml \
  '<create_credential>
    <name>Linux SSH Password</name>
    <type>up</type>
    <login>scan_user</login>
    <password>scan_password_here</password>
  </create_credential>'

SMB Credentials for Windows Targets

# Create SMB credential for Windows authenticated scanning
gvm-cli socket --socketpath /run/gvmd/gvmd.sock --gmp-username admin --gmp-password <password> --xml \
  '<create_credential>
    <name>Windows SMB Cred</name>
    <type>up</type>
    <login>DOMAIN\scan_account</login>
    <password>smb_password_here</password>
  </create_credential>'

ESXi Credentials

# Create ESXi credential for VMware host scanning
gvm-cli socket --socketpath /run/gvmd/gvmd.sock --gmp-username admin --gmp-password <password> --xml \
  '<create_credential>
    <name>ESXi Root</name>
    <type>up</type>
    <login>root</login>
    <password>esxi_password_here</password>
  </create_credential>'

Creating Scan Targets

# Create target with SSH credential (Linux hosts)
gvm-cli socket --socketpath /run/gvmd/gvmd.sock --gmp-username admin --gmp-password <password> --xml \
  '<create_target>
    <name>Linux Production Servers</name>
    <hosts>192.168.1.10,192.168.1.11,192.168.1.12</hosts>
    <port_list id="33d0cd82-57c6-11e1-8ed1-406186ea4fc5"/>
    <ssh_credential id="CREDENTIAL_UUID_HERE">
      <port>22</port>
    </ssh_credential>
    <alive_test>ICMP, TCP-ACK Service and ARP Ping</alive_test>
  </create_target>'

# Create target with SMB credential (Windows hosts)
gvm-cli socket --socketpath /run/gvmd/gvmd.sock --gmp-username admin --gmp-password <password> --xml \
  '<create_target>
    <name>Windows Domain Controllers</name>
    <hosts>192.168.1.20,192.168.1.21</hosts>
    <port_list id="33d0cd82-57c6-11e1-8ed1-406186ea4fc5"/>
    <smb_credential id="SMB_CREDENTIAL_UUID_HERE"/>
    <alive_test>ICMP, TCP-ACK Service and ARP Ping</alive_test>
  </create_target>'

Scan Configuration

This section covers scan configuration for performing authenticated scan with openvas.

Ensure all prerequisites are met before proceeding
Follow the documented workflow steps in sequence
Record results and any anomalies encountered during this phase

Built-in Scan Configs

Config Name	OID	Use Case
Full and fast	daba56c8-73ec-11df-a475-002264764cea	Standard production scan
Full and deep	708f25c4-7489-11df-8094-002264764cea	Thorough scan, may be disruptive
System Discovery	8715c877-47a0-438d-98a3-27c7a6ab2196	Host and service enumeration

Create Custom Scan Config for Authenticated Scan

# Clone "Full and fast" config and customize
gvm-cli socket --socketpath /run/gvmd/gvmd.sock --gmp-username admin --gmp-password <password> --xml \
  '<create_config>
    <copy>daba56c8-73ec-11df-a475-002264764cea</copy>
    <name>Authenticated Full Scan</name>
  </create_config>'

Running the Scan

This section covers running the scan for performing authenticated scan with openvas.

Ensure all prerequisites are met before proceeding
Follow the documented workflow steps in sequence
Record results and any anomalies encountered during this phase

Create and Start Scan Task

# Create scan task
gvm-cli socket --socketpath /run/gvmd/gvmd.sock --gmp-username admin --gmp-password <password> --xml \
  '<create_task>
    <name>Weekly Authenticated Scan - Linux Prod</name>
    <config id="CONFIG_UUID"/>
    <target id="TARGET_UUID"/>
    <scanner id="08b69003-5fc2-4037-a479-93b440211c73"/>
  </create_task>'

# Start the scan task
gvm-cli socket --socketpath /run/gvmd/gvmd.sock --gmp-username admin --gmp-password <password> --xml \
  '<start_task task_id="TASK_UUID"/>'

# Check scan progress
gvm-cli socket --socketpath /run/gvmd/gvmd.sock --gmp-username admin --gmp-password <password> --xml \
  '<get_tasks task_id="TASK_UUID"/>'

Schedule Recurring Scans

# Create weekly schedule (every Sunday at 2:00 AM UTC)
gvm-cli socket --socketpath /run/gvmd/gvmd.sock --gmp-username admin --gmp-password <password> --xml \
  '<create_schedule>
    <name>Weekly Sunday 2AM</name>
    <icalendar>
BEGIN:VCALENDAR
VERSION:2.0
BEGIN:VEVENT
DTSTART:20240101T020000Z
RRULE:FREQ=WEEKLY;BYDAY=SU
DURATION:PT12H
END:VEVENT
END:VCALENDAR
    </icalendar>
    <timezone>UTC</timezone>
  </create_schedule>'

Exporting Results

# Export scan report as XML
gvm-cli socket --socketpath /run/gvmd/gvmd.sock --gmp-username admin --gmp-password <password> --xml \
  '<get_reports report_id="REPORT_UUID" format_id="a994b278-1f62-11e1-96ac-406186ea4fc5"/>'

# Export as CSV
gvm-cli socket --socketpath /run/gvmd/gvmd.sock --gmp-username admin --gmp-password <password> --xml \
  '<get_reports report_id="REPORT_UUID" format_id="c1645568-627a-11e3-a660-406186ea4fc5"/>'

# Use python-gvm for programmatic access
python3 -c "
from gvm.connections import UnixSocketConnection
from gvm.protocols.gmp import Gmp
from gvm.transforms import EtreeCheckCommandTransform

connection = UnixSocketConnection(path='/run/gvmd/gvmd.sock')
transform = EtreeCheckCommandTransform()
with Gmp(connection=connection, transform=transform) as gmp:
    gmp.authenticate('admin', 'password')
    reports = gmp.get_reports()
    print(f'Total reports: {len(reports)}')
"

Validating Authentication Success

# Check if credentials were accepted during scan
# In the scan report, look for NVT "Authentication tests" results:
# - OID 1.3.6.1.4.1.25623.1.0.103591 (SSH authentication successful)
# - OID 1.3.6.1.4.1.25623.1.0.90023 (SMB authentication successful)

# Verify via gvm-cli
gvm-cli socket --socketpath /run/gvmd/gvmd.sock --gmp-username admin --gmp-password <password> --xml \
  '<get_results filter="name=SSH rows=10 sort-reverse=severity"/>'

When NOT to Use

You don't have explicit written authorization to test
Task is about defense/detection, not offense (use detection skills)
You need to implement security controls (use implementing-* skills)
Task requires compliance auditing (use auditing-* skills)
You're investigating an incident (use incident response skills)
Target is out of scope for your engagement
Task is about vulnerability scanning only (use scanning tools)

Red Flags

Performing actions without explicit written authorization from the asset owner
Testing against production systems without a defined scope and rules of engagement
Sharing sensitive findings or credentials in unencrypted communications
Failing to properly scope and contain the assessment before starting

Verification

All steps executed successfully against a test environment before production use
Output documented with screenshots or logs demonstrating expected behavior
Results validated against known-good baselines or reference implementations
Documentation complete enough for another analyst to reproduce findings

References

Process

Analyze the task requirements
Apply domain expertise
Verify output quality