Hacking, Virus, Worm, Trojanhorse, Malware

Hacking

Hacking is identifying weakness in computer systems or networks to exploit its weaknesses to gain access. Example of Hacking: Using password cracking algorithm to gain access to a system

A Hacker is a person who finds and exploits the weakness in computer systems and/or networks to gain access. Hackers are usually skilled computer programmers with knowledge of computer security.

Hackers are classified according to the intent of their actions. The following list classifies hackers according to their intent.

Ethical Hacker (White hat): A hacker who gains access to systems with a view to fix the identified weaknesses. They may also perform penetration Testing and vulnerability assessments.

Cracker (Black hat): A hacker who gains unauthorized access to computer systems for personal gain. The intent is usually to steal corporate data, violate privacy rights, transfer funds from bank accounts etc.

Grey hat: A hacker who is in between ethical and black hat hackers. He/she breaks into computer systems without authority with a view to identify weaknesses and reveal them to the system owner.

Script kiddies: A non-skilled person who gains access to computer systems using already made tools.

Hacktivist: A hacker who use hacking to send social, religious, and political, etc. messages. This is usually done by hijacking websites and leaving the message on the hijacked website.

Phreaker: A hacker who identifies and exploits weaknesses in telephones instead of computers.

Virus

• A virus is a computer program that attaches itself to legitimate programs and files without the user’s consent. Viruses can consume computer resources such as memory and CPU time. The attacked programs and files are said to be “infected”. A computer virus may be used to;

• Access private data such as user id and passwords
• Display annoying messages to the user
• Corrupt data in your computer
• Log the user’s keystrokes

Computer viruses have been known to employ social engineering techniques. These techniques involve deceiving the users to open the files which appear to be normal files such as Word or Excel documents. Once the file is opened, the virus code is executed and does what it’s intended to do.

Worm

A worm is a malicious computer program that replicates itself usually over a computer network. An attacker may use a worm to accomplish the following tasks;

• Install backdoors on the victim’s computers.  The created backdoor may be used to create zombie computers that are used to send spam emails, perform distributed denial of service attacks, etc. the backdoors can also be exploited by other malware.
• Worms may also slowdown the network by consuming the bandwidth as they replicate.
• Install harmful payload code carried within the worm.

Trojan Horse

A Trojan horse is a program that allows the attack to control the user’s computer from a remote location. The program is usually disguised as something that is useful to the user. Once the user has installed the program, it has the ability to install malicious payloads, create backdoors, install other unwanted applications that can be used to compromise the user’s computer, etc.

The list below shows some of the activities that the attacker can perform using a Trojan horse.

• Use the user’s computer as part of the Botnet when performing distributed denial of service attacks.
• Damage the user’s computer (crashing, blue screen of death, etc.)
• Stealing sensitive data such as stored passwords, credit card information, etc.
• Modifying files on the user’s computer
• Electronic money theft by performing unauthorized money transfer transactions
• Log all the keys that a user presses on the keyboard and sending the data to the attacker. This method is used to harvest user ids, passwords, and other sensitive data.
• Viewing the users’ screenshot
• Downloading browsing history data

Malware

Malware, or malicious software, is any program or file that is harmful to a computer user. Types of malware can include computer viruses, worms, Trojan horses and spyware. These malicious programs can perform a variety of different functions such as stealing, encrypting or deleting sensitive data, altering or hijacking core computing functions and monitoring users’ computer activity without their permission.

Malware authors use a variety of physical and virtual means to spread malware that infect devices and networks. For example, malicious programs can be delivered to a system with a USB drive or can spread over the internet through drive-by downloads, which automatically download malicious programs to systems without the user’s approval or knowledge. Phishing attacks are another common type of malware delivery where emails disguised as legitimate messages contain malicious links or attachments that can deliver the malware executable to unsuspecting users. Sophisticated malware attacks often feature the use of a command-and-control server that allows threat actors to communicate with the infected systems, exfiltrate sensitive data and even remotely control the compromised device or server.