Hackers4m: Introduction to Penetration Testing

This article is just to give you the Basic knowledge and making you understand the Fundamentals of Penetration Testing

Goal of this Article

An overview of how Vulnerability Assessment (VA) & Penetration Testing (PT) is done
qDefining scope of the assessment
qTypes of Penetration Testing
qA brief understanding on how Buffer Overflow works
qHow vulnerabilities are scanned and exploited
qWhat are the end results
qWhat a Penetration Testing Report should contain

Differentiating VA and PT

Vulnerability Assessment (VA)

In this case the security auditor has to only scan for the vulnerabilities in the server or application and filter out the false positives from the scan output by mapping them with the actual vulnerabilities associated with the target host.

VA Scope Includes:

• The VA test can be done both internally and externally

• No vulnerabilities are exploited

• No dangerous attacks like DOS and Buffer Overflow attacks are used

• Automated vulnerability scanning tools line Nessus, Retina or ISS are used

Penetration Testing (PT)

In this case the security auditor or the penetration tester not only has to scan for the vulnerabilities in the server or application but also has to exploit them to gain access to the remote server.

PT Scope Includes:

• The PT test is done both internally and externally

• Vulnerabilities are exploited

• Dangerous attacks like DOS and Buffer Overflow attacks are used depending upon

the customer’s willingness to do so

• Automated vulnerability scanning tools and as well as exploits are used

Types Of Penetration Testing

Black Box Penetration Testing

Pen tester has no previous knowledge of the remote network

• Simulating a real world hacking by a hacker who has no knowledge

(E.g. Operating System running, application running, device type and

network topology etc..) of the remote network environment

White Box Penetration Testing

• Have the knowledge of the remote network
•Type of Pen tester network devices (i.e. Cisco gear, TCP/IP),
•WebServer details (i.e., Apache/*nix or Apache/Win2k),
•Operating System type (i.e., Windows/*nix),
•Database platform (i.e., Oracle or MS SQL),
•Load balancers (i.e. Alteon),
Firewalls (i.e. Cisco PIX).. etc
•Simulating a attack by a hacker who is having a detailed knowledge of the remote network environment

Scope Of Penetration Testing

Non-Destructive Test

•Scans the remote hosts for possible vulnerabilities
•Analyze and confirm the findings
•Map the vulnerabilities with proper exploits
•Exploit the remote system with proper care to avoid disruption of service
•No highly critical Denial of Service (DoS) attack is tried

Destructive Test

•Scans the remote hosts for possible vulnerabilities
• Analyze and confirm the findings
• Map the vulnerabilities with proper exploits
•All highly critical Denial of Service (DoS) attacks (e,g like buffer overflows are tried

~~~ Moving On To Penetration Testing ~~~

Penetration testing includes some steps ...

qFingerprinting or Footprinting
qNetwork Information Gathering
qSurveying / Network Mapping
qPorts Scanning and Services Identification
qEvading Firewall Rules
qAutomated Vulnerability Scanning
qExploiting Services for Known Vulnerabilities
qExploiting Web-Based Authorization
qPassword Cracking / Brute Forcing
qDenial of Services (DoS) Testing
qEscalation of Privileges

FLOW CHART

1. Information Gathering

This is the first step for any remote host Penetration Testing. Here the pen-tester try to gather maximum information on the remote host to precise the attack.

Expected Results:

qZone Transfer Information
q Domain Registration Information
q Email IDs
q IP Addresses Range

Sample Screenshot (Server queried for Zone-Transfer Info):

(Information Gathered from Zone-Transfer Info)

2. Footprinting / Fingerprinting

In this step, information like WebServer and OS type running on remote host are gathered to further precise the attack.

Expected Results:

qRemote server OS type
q Remote server web-server type
q Applications running on remote server

Sample Screenshot (Banner displaying OS, application & WebServer details):

3. Network Surveying / Network Mapping

A network survey serves often as an introduction to the systems to be tested. It is best defined as a combination of data collection, information gathering, and policy control.

Expected Results:

qFirewall / Routers / IDS Discovery
qPossible Local Network / Subnet Discovery
qIP Addresses Range
qNetwork Topology Mapping
qISP information

Sample Screenshot (Local address of the remote network discovered):

4. Port Scanning & Services Identification

Port scanning is the invasive probing of system ports on the transport and network level. This module is to enumerate live or accessible Internet services as well as penetrating the firewall to find additional live systems.

Expected Results:

qOpen, closed or filtered ports
qServices Identification

Sample Screenshot (NMAP port scan output):

5. Evading Firewall Rules

In this phase, firewall evasion techniques are used to bypass firewall rules. This can further help in port scanning, remote host detection and remote network discovery.

Expected Results:

q Mapping of firewall configuration rules
q Partial Access to devices behind the firewall

Sample Screenshot : (Trace Route using UDP packets)

It is clear from the two screenshots that the packet filtering device (i.e. Firewall / Router) is not configured to block UDP packets.

6. Automated Vulnerability Scanning

The focus of this module is identifying, understanding, and verifying the weaknesses, misconfigurations and vulnerabilities associated with remote host. The scanning is done using automated tools or scripts to make the process faster.

Expected Results:

qList of vulnerabilities associated with each remote services
qList of possible denial of service vulnerabilities
qPossible misconfiguration on the remote server

Sample Screenshot

What is MVS ?

MVS is an automated Internet Vulnerability Scanner which can scans for web based vulnerabilities (Ex: CGI/IIS Unicode) associated with a remote host running a web server. The scanner displayed, shows that the target host is vulnerable to IIS Unicode. The vulnerable string has been highlighted in the below screen shot

7. Exploiting Services For Known Vulnerabilities

This is the most important phase of penetration testing. Here the weaknesses found in the remote services are exploited using openly available exploits or self developed or customized exploits.

Expected Results:

q Gaining Access to the system
q Retrieving hidden information
q Domain Hijacking
q Spamming Mail Servers

Sample Screenshot (FrontPage fp30reg.dll Overflow Exploit):

Here the web application flaws are exploited to gain access to restricted information. The Web-Based authentication is exploited by using XSS (Cross-Site Scripting) or SQL injection or MITM (Man-in-the-middle) attacks etc...

Expected Results:

qAccess to restricted / confidential information
q Control over web configuration
q Can also leads to gaining access over other servers

Sample Screenshot (SQL injection used for gaining access to admin page):

8. Password Cracking or Brute Forcing

Password cracking is the process of validating password strength through the use of automated password recovery tools that expose either the application of weak passwords due to human factors.

Password Lists and Words List are use for validating the password in this process

Expected Results:

qList of user login IDs or passwords
q List of authentication PINs or Password

Sample Screenshot (Brute Forcing using Brutus):

9. Denial of Service (DoS) Testing

Denial of Service (DoS) is a situation where the applications or services running over the remote system stops functioning and prevents authenticated network users or devices to access it.

Expected Results:

Disruption of Services
q List of other possible DoS vulnerable associated with the systems
qSabotage of remote network

Sample Screenshot (DOS attack for CISCO):

10. Escalation of Privileges

Escalation of Privileges is the type of rights the attacker gains over the remote system. It is the final stage of the remote host hacking where the attacker gains complete control over the remote system.

Expected Results: