CCNA CyberOps Chapter 6 Exam Online

White hat attackers break into networks or computer systems in order to discover weaknesses for the purpose of improving the security of these systems. These break-ins are done with permission from the owner or the organization. Any results are reported back to the owner or the organization.

Hackers are categorized by motivating factors. Hacktivists are motivated by protesting political and social issues.

Spyware normally installs on a system without end-user knowledge and monitors activity on a computer, which can then be sent to the source of spyware. Viruses infect systems and execute malicious code. Worms self-replicate and propagate across networks from a singular host, consuming a lot of bandwidth. Adware is normally distributed through downloaded software and results in the exhibition of several pop-up windows on the system.

A virus is malicious code that is attached to a legitimate program or executable file, and requires specific activation, which may include user actions or a time-based event. When activated, a virus can infect the files it has not yet infected, but does not automatically propagate itself to other systems. Self-propagation is a feature of worms. In addition to being distributed over the Internet, viruses are also spread by USB memory sticks, CDs, and DVDs.

A computer can have a worm installed through an email attachment, an executable program file, or a Trojan Horse. The worm attack not only affects one computer, but replicates to other computers. What the worm leaves behind is the payload–the code that results in some action.

The main purpose of a worm is to self-replicate and propagate across the network. A virus is a type of malicious software that needs a user to spread. A trojan horse is not self-replicating and disguises itself as a legitimate application when it is not. A botnet is a series of zombie computers working together to wage a network attack. ​

A Trojan horse carries out malicious operations under the guise of a legitimate program. Denial of service attacks send extreme quantities of data to a particular host or network device interface. Password attacks use electronic dictionaries in an attempt to learn passwords. Buffer overflow attacks exploit memory buffers by sending too much information to a host to render the system inoperable.

The attacker uses a proxy Trojan horse attack to penetrate one device and then use that device to launch attacks on other devices. The DoS Trojan horse slows or halts network traffic. The FTP trojan horse enables unauthorized file transfer services when port 21 has been compromised. A data-sending Trojan horse transmits data back to the hacker that could include passwords.

Hackers use rootkits to avoid detection as well as hide any software installed by the hacker.

Scareware is a type of malware that attempts to shock or induce anxiety by creating a perception of a threat. Phishing tries to get the user to divulge some information. A DoS attack tries to disrupt service on a network. Adware usually appears in pop-ups trying to get the user to buy something or to visit a website.

Ransomware involves the hackers preventing user access to the infected and controlled system until the user pays a specified amount.

Common symptoms of computers infected with malware:Appearance of files, applications, or desktop icons
Security tools such as antivirus software or firewalls turned off or changed
System crashes
Emails spontaneously sent to others
Modified or missing files
Slow system or browser response
Unfamiliar processes or services running
Unknown TCP or UDP ports open
Connections made to unknown remote devices

Phishing is used by malicious parties who create fraudulent messages that attempt to trick a user into either sharing sensitive information or installing malware.

A denial of service (DoS) attack attempts to overwhelm a system or process by sending large amounts of data or requests to the target. The goal is to keep the system so overwhelmed handling false requests that it is unable to respond to legitimate ones.

By sending too much data to a specific area of memory, adjacent memory locations are overwritten, which causes a security issue because the program in the overwritten memory location is affected.

Gathering information about a network and scanning for access is a reconnaissance attack. Preventing other users from accessing a system is a denial of service attack. Attempting to retrieve and modify data, and attempting to escalate access privileges are types of access attacks.

Gathering information about a network and scanning for access is a reconnaissance attack. Preventing other users from accessing a system is a denial of service attack.

An access attack tries to affect services that affect entry into accounts, databases, and other sensitive information. Access attacks commonly involve a dictionary ths is used to guess a specific user password. A brute-force access attack would try to access an account via repeated attempts.

An access attack tries to gain access to a resource using a hijacked account or other means. The five types of access attacks include the following:password – a dictionary is used for repeated login attempts
trust exploitation – uses granted privileges to access unauthorized material
port redirection – uses a compromised internal host to pass traffic through a firewall
man-in-the-middle – an unauthorized device positioned between two legitimate devices in order to redirect or capture traffic
buffer overflow – too much data sent to a memory location that already contains data

A ping sweep is a tool that is used during a reconnaissance attack. Other tools that might be used during this type of attack include a ping sweep, port scan, or Internet information query. A reconnaissance attack is used to gather information about a particular network, usually in preparation for another type of network attack.

Zombies are infected computers that make up a botnet. The zombies are used to deploy a distributed denial of service (DDoS) attack.

Spear phishing is a phishing attack customized to reach a specific person or target.

One method of executing a DDoS attack involves using a botnet. A botnet builds or purchases a botnet of zombie hosts, which is a group of infected devices. The zombies continue to create more zombies which carry out the DDoS attack.

The following methods are used by hackers to avoid detection:Encryption and tunneling – hide or scramble the malware content
Resource exhaustion – keep the host device too busy to detect the invasion
Traffic fragmentation – split the malware into multiple packets
Protocol-level misinterpretation – sneak by the firewall
Pivot – use a compromised network device to attempt access to another device
Rootkit – allow the hacker to avoid detection as well as hide software installed by the hacker

Denial of service (DoS) attacks attempt to disrupt service on the network by either sending a particular device an overwhelming amount of data so no other devices can access the attacked device or by sending malformed packets.

Phishing is an attempt to get a user to divulge information. Vishing is a type of phishing that uses voice and the phone system. With pretexting, the hacker lies to the user in an attempt to obtain information.