Investigation Questions On Linux Security Workbook 2 Assignment 6 Answer
What does the sudo command do and why is it needed?
Answer – the sudo command allow us to execute a command or program with root privileges. As the root account has higher security level and have administrator level access of all the system resources. When a command is executed from terminal, it asks for root password and verify it from a file named as sudoers. This file has a list of administrator level users with their access rights. There are a lot of commands which can be executed with sudo command, as a syntax of - $ sudo command. The system administrator can configure the sudoers file to allow or limit access of as a root user by any user in the system. It logs all the arguments and commands, record it with the details of accessed user, purpose and result of that execution (University, 2021).
Explain basic Unix file permissions in detail, including what gets shown using the ls -l command and what the chmod command does.
Answer – every user permission is associated with three different types of permissions as user, group and other permission. Here are these ("Unix Permissions: File Permissions in Unix with Examples", 2021) –
- User – it specifies the access level of a user with a user ID
- Group – it specifies the access level of a user group with a group ID
- Other – it specifies the access level of a user without any user ID or group ID
Here are the basic UNIX permissions –
- Read – user is authorized to read the file
- Write – user is authorized to write the file
- Execute – user is authorized to execute the file
The ls command is used to listing of the files and folders in a directory or directory path. It works with different switches, as when it used with -l switch, it shows the long listing of files and folders contained in a directory ("The Command Line with ls -l", 2018).
The chmod command is used to change the mode of access of a file. It uses references, operator and mode in its syntax with the file name. The references are u for owner, g for group, o for others and a for all. To add a permission to a file a add (+) operator is used, to remove permission minus (-) operator is used and to define exact mode of permission an equal (=) operator is used ("chmod command in Linux with examples - GeeksforGeeks", 2017).
Home computer security
How might you secure a home computer and its associated network? List three key points and justify them.
Answer – here are the key points which helps in securing a home computer and associated network –
|Locking of device||As a primary step, one should use strong password and keep lock both computer system and access of network using this method. We can use limit access of network, use encryption, security protocols like SSH, HTTPS, SSH, VPN and use strong security to access the device.|
|Enable security of the internet router||The internet router should be reset from its factory settings such as change of its default SSID, name, password, security options, etc. If there is an option to enable internal firewall in the router, use it and keep the firmware to the latest.|
|Use of firewall and antivirus program||Use of a firewall in the network and antivirus application on the computer systems will help in keeping them safe from any attack.|
(Bocetta & Bocetta, 2015) ("Securing Your Home Network - Stay Safe Online", 2014)
Overview the features of a firewall as might be used in a large organisation like QUT.
Answer – when choosing an appropriate firewall to work with a large organisation, one has to keep so many things in mind related to the selection of the best firewall for their network. Here are those key features ("Choosing a Firewall: the Most Important Features and Types You Need to Know | Solid State Systems LLC", 2019) –
- High availability – it is a standard feature of a firewall which protect internal network from external attack with high availability. This feature offers all the time protection even when a network is down.
- Virtual private network – a VPN help in safeguarding a network by encrypting the communication between devices. It can be of many types depending and offered by a firewall vendor.
- Filtering of packet – a firewall can be configured to filter packets which passed through a firewall. It then blocks or allow packets to pass in or to the network.
- Stateful inspection – this feature will inspect the headers of packets and offer advance protection in the network.
- Proxy – a firewall can be work as a proxy server. It will change our IP address and make the traffic acting as transitional between internet and a computer system. It uses encryption with the connection and provide more security to a network.
- Size of network – it is more crucial approach while considering a large network. Based on the size of network, a firewall is to be used, single and multiple firewalls with different technologies like stateful, host-based or network firewall, will be chosen.