Lecture 13 - Firewall and Malware

Firewall and why we use it

a router or special-purpose device that examines packets flowing into and out of a network and restricts access to the organization's network.

use it for security: no access is permitted except through the firewall

3 types of firewall

Packet-level firewall

Application-level firewall

Network Address Translation (NAT) firewall

packet-level firewall

examines IP addresses (source and destination)

examines TCP port ID

simplest, least secure, logic independent of other packets

Application-level firewall

monitors connections

uses rules to determine what client may do, e.g., no executable files, no change on files, etc.

performs checks against known security holes for each application

expensive and may slow network

Network Address Translation (NAT) firewall

transparent process

hides Internal IP address, assigns public address

sometimes used to conserve IP addresses

uses address table relating "port number" to internal computer

Malware or malicious software

any program or file that is harmful to a computer user

Virus

malicious code that replicates by copying itself to another program, computer boot sector or document and changes how a computer works.

used WITH human intervention

Worm

special type of virus that spreads itself WITHOUT human intervention.

trojan horse

remote access management consoles (sometimes called rootkits) that enable users to access a computer and manage it from afar.

Spyware

software that aims to gather information about a person or organization, sometimes without their knowledge, that may send such information to another entity without the consumer's consent, that asserts control over a device without the consumer's knowledge

Ransomware

malicious software, or malware, designed to deny access to a computer system or data until a ransom is paid.

ways to prevent malware

Use security (antivirus) software.

Keep your security software up to date.

Update your operating system and other software

Don't automatically open email attachments.

Be wary of any email attachment that advises you to enable macros to view its content.

Back up important data to an external hard drive.