本文是计算机专业的留学生作业范例，题目是“Ethical Hacking And Attacking Computer Science Essay（道德黑客和攻击计算机科学论文）”，黑客行为是否道德是有争议的，随着时间的推移，“黑客”一词一直与破坏性活动联系在一起。这是一些在黑客语境中使用的术语，使其更加清晰。
It is debatable, if hacking can be ethical or not, the term "Hacking" over time has been associated with destructive activity.These are some of the terms used in the context of hacking which provides better clarity, Hacker is somebody who enjoys learning hacking for a defensive purpose; an ethical hacker is the security professional who exercises his skills for a defensive purpose. The term Cracker refers to a person who uses his hacking skills for destructive purpose.
The ethical question here is in regard to the physical activity of hacking which is sometimes hard to differentiate from cracking. The main difference being, Ethical hacker just identifies vulnerabilities and does not exploit them unlike a cracker.Ethical hacking is the process adopted by ethical hackers to discover the vulnerabilities existing in information systems operating environments.
Reconnaissance is the preparatory phase where an attacker gathers information about the target system prior to launching the attack. This phase might also involve network scanning either internal or external without any authorization.
One of the ways for gathering information during this phase may involve "Social engineering". A social engineer is a person who smooth-talks and persuades people to reveal personal / sensitive information such as passwords, security policies etc. Social engineering is one of the easiest ways to hack as it requires no technical skills and one of the hardest forms of attack to defend against as humans are the weakest link in the security chain. All security measures taken care by the organization goes in vain when the employees get "social engineered". Detecting social engineering attacks are difficult, as there is no tool to detect such attempts, in most of the cases victim themselves are not aware having revealed sensitive information. "Rebecca" and "Jessica" are the common terms used, which refer to people who are easy target for social engineering attacks such as a receptionist or a support executive.
"Dumpster diving" is another way of gathering information. It is the process of looking for discarded sensitive information in an organization thrash. It is one of the effective ways of gathering information as it may provide attackers with even more sensitive information such as username, password, ATM slip, social security number, Bank statements.
It is important that an organization has appropriate policies in place to protect their assets and also provide proper guidance to employees on the same.
Reconnaissance technique can be classified into active and passive reconnaissance.
In passive reconnaissance, the attacker does not interact with the system directly but uses social engineering or dumpster diving as a mean to gather information. Where as in a active reconnaissance, the attacker makes use of tools for port scanning, network scanning to get the details of the application, operating system etc. Often reconnaissance phase overlaps with the scanning phase.
Scanning precedes the actual attack and is one of the important phase of information gathering where in the attacker gathers information about the targets IP address , operating system , system architecture , services running in the system in order to find various ways to intrude into targets system. The strategy to launch the attack is based on the gathered information. The risk of an organization is considered high in the scanning phase as it enables access to the network.
Different types of scanning are
Port Scanning: Procedure for identifying the open ports and the services running on the target system.
Network Scanning -Procedure for identifying IP addresses, active hosts on a network either to attack them or as a network security assessment.
Vulnerability Scanning -Automates method to identify the known vulnerabilities present in the system and the network.
Some of the important tools used during this phase are Nmap which is used for port scanning; it also offers a variety of advanced features such as remote OS detection.
Nessus is a vulnerability scanner which detects the local flaws, uninstalled patches and weakness in network hosts. Nessus has a security vulnerability database which is updated on a daily basis. It carries out development of security checks for recent security holes.
3.Gaining Access 获得
This is one of the most important phases for an attack as this is where the actual attack is planted. Therefore the business risk is highest in this phase. Although not a mandatory phase as an attacker need not always gain access to cause damage like in denial of service attacks.
The main aim in this phase is to obtain elevated privileges such as system privilege to execute commands to access sensitive information.
4.Maintaining Access 维护访问
Once the attacker gains access into the system or the network, he tries to retain his "ownership" on the compromised system and periodically attack it. Typically in this phase the attacker tries to install Key loggers to capture the keyboard strokes, sniffers to capture network traffic, rootkits at the kernel level to gain super user access and Trojan horse to gain repeated backdoor access, also download the password files to access the system at a later time. Once the Trojans are in place, the attacker can assume to have gained total control of the system.
During this phase the attackers might even harden the system against other attackers by fixing the vulnerability which allowed them to access the system or the network.
5.Clearing Tracks 清除痕迹
This is where the attacker tries to cover the evidence of his activities for various reasons like maintaining access or legal actions. During this phase the attacker deletes the system logs preventing the system administrator from monitoring the unusual activity, Rootkits are installed as they are effective in covering tracks and also because in some cases they disable logging.
Other techniques like Steganography which is used to hide the data in a image or a file, are made used by the attacker in order to cover tracks.
6.Google Hacking 谷歌黑客
Google Hacking is the art of creating complex search queries in order to gather information of the target system. Google is the primary tool used for Google hacking. Advanced Google operators are used to filter information.
Google hacking database identifies files containing password, sensitive directories, vulnerable web pages, error messages containing sensitive information, pages containing firewall logs etc.
In recent times Web applications are the target of various forms of attacks. According to a Gartner report 70% of the security attacks are targeted on the web application. Competition is so high that enterprises can't ignore the risk associated with their vulnerable application. Loss incurred could vary from monetary losses to loss of credibility. In certain cases it could mean end of business. You cannot stop an attacker from hacking, the only thing you can do is make it harder to get in.Ethical hackers are the security professionals who use their hacking skills for defensive purpose. The process of ethical hacking would depend on, what is that organization is trying to protect, against whom and how much or resources the organization is ready to spend. The hacking tools are meant for research and educational purpose only and should not be used for destructive purpose.