From d5a53001e0b32ee27bf4c67735f5fe849b528323 Mon Sep 17 00:00:00 2001 From: Jet Hughes Date: Mon, 20 Mar 2023 09:24:23 +1300 Subject: [PATCH] vault backup: 2023-03-20 09:24:23 --- .../notes/06-network-system-administration.md | 91 +++++++++++++++++++ content/notes/07-system-installation.md | 8 ++ content/notes/cosc-301.md | 2 +- content/notes/cosc-342.md | 2 +- content/notes/info-305.md | 6 +- 5 files changed, 104 insertions(+), 5 deletions(-) create mode 100644 content/notes/06-network-system-administration.md create mode 100644 content/notes/07-system-installation.md diff --git a/content/notes/06-network-system-administration.md b/content/notes/06-network-system-administration.md new file mode 100644 index 000000000..ae70752e0 --- /dev/null +++ b/content/notes/06-network-system-administration.md @@ -0,0 +1,91 @@ +--- +title: "06-network-system-administration" +tags: +- lecture +- cosc301 +--- + + +security awareness +- physical and network attacks +- [[security]] + +Computer/Internet hazards +- SPAM/UCE (Unsolicited Commercial Email) +- Phishing +- Disk crashes/data loss +- Loss of services due to outage +- TCP/IP spoofing and sniffing (privacy) +- Pornography +- Ignorant users +- Grumpy (former) employees +- Administrators of the untrained kind + +broken symlink +- broken symlilnk/softlink can be a risk +- If it is pointing to a location that is accessible by an attacker, it ends up retrieving a file belong to the attacker. +- If it is a web server, you end up retrieve and present the attacker’s information. +- Solution: NO_FOLLOW flag to stop following the symlink. + +Roles in network community +- Important roles include users, hosts, network components e.g. routers and operating systems. + - Users - should be trained to be aware of the community. Human beings are usually the weakest link. + - Host machines - should be allocated different tasks on different server machines + - Routers/gateways + - affect network security and performance + - OS - have different pros and cons + - UNIX/Linux, Windows, MAC OS, Netware + + +Host Management +- Shutting down a host + - Turn off the power? + - Should use command shutdown + - shutdown -h time halt the system. time can be now. + - shutdown -r time reboot the system +- Log files and audits: health barometer of a host + - syslogd: a daemon for logging messages. Its configuration file is /etc/syslog.conf + - dmesg: check kernel messages + - lastlog: check the last login time of every user + - syslog under /var/log: the log file of the system + - They should be rotated regularly + +User Management +- User account + - Includes all the files, resources, and info belonging to one user. For commercial systems, it may include billing info. +- Create a new account + - adduser + - Account info: username, password, user id, group id, full name of user, home directory, login shell + - In the /etc/passwd file, + - Amber:x:1000:100:Amber Dawn:/home/amber:/bin/bash + - Check after adding +- Involved files + - /etc/passwd, /etc/group, /etc/shadow + - In /etc/shadow, + - Chloe:$2a$05$wa7xVOqOH4lVOrh.qa9ivSX0G0QUCFqbk11YV6:14743:0:99999:7::: + - Username:encrypted password:last password change:minimum:expiration:warning:disabled:diabled date:reserved +- User login environment + - .bash_profile, .bashrc, /etc/profile + - Place global files such as profile under /etc +- Other scripts can be referred in it + - Use env/set to check/set your environment +- Paths and prompts + - Keep a copy of your shell scripts (initial setups) in order to survive them from upgrade of OS/software +- For more detailed info, man bash +- Password + - Very important for security + - Should not be names of persons, books, places, your computer, nor your phone number, birthday, car registration plate, login name, words in dictionaries, keyboard sequence + - Should be composed of letters (lower and upper cases), digits, and special characters like $,@ + - Refer to http://en.wikipedia.org/wiki/Password_strength + - passwd imposes similar rules to make passwords secure. + - Change frequently +- User id and group id + - Users should be divided into groups for security reasons, e.g. students, staff, admin + - Special users/groups: nobody, mail, ftp +- addgroup + - In /etc/group, + - video:x:33:hzy,paul,kai + - Group name:password:group id;list of members + +- Remove a user: deluser – The relevant lines from /etc/passwd, /etc/group, and /etc/shadow will be removed. – It is a good idea to first disable the account before you start removing stuff +- Disable a user temporarily – A better way when you are not sure if a user will come back – Way 1: Put an * in the password field of /etc/shadow – Way 2: use passwd -{l|u} username – Way 3: Change the login shell to a script file \ No newline at end of file diff --git a/content/notes/07-system-installation.md b/content/notes/07-system-installation.md new file mode 100644 index 000000000..1db2ce49a --- /dev/null +++ b/content/notes/07-system-installation.md @@ -0,0 +1,8 @@ +--- +title: "07-system-installation" +tags: +- lecture +- cosc301 +--- + + diff --git a/content/notes/cosc-301.md b/content/notes/cosc-301.md index 965b1fdea..77d406d3e 100644 --- a/content/notes/cosc-301.md +++ b/content/notes/cosc-301.md @@ -33,5 +33,5 @@ https://www.cs.otago.ac.nz/cosc301/schedule.php - [x] [[04-scripting-techniques]] - [x] [[05-filesystems]] - [[06-network-system-administration]] -- +- [[07-system-installation]] # Info diff --git a/content/notes/cosc-342.md b/content/notes/cosc-342.md index d209dc962..9332b3d75 100644 --- a/content/notes/cosc-342.md +++ b/content/notes/cosc-342.md @@ -22,7 +22,7 @@ tags: - [x] [[03-2d-transforms]] - [[04-mosaicing]] - [x] [[05-feature-description-and-matching]] -- [ ] [[06-homographies]] +- [x] [[06-homographies]] # Info diff --git a/content/notes/info-305.md b/content/notes/info-305.md index 3c49f2261..642eeb891 100644 --- a/content/notes/info-305.md +++ b/content/notes/info-305.md @@ -17,9 +17,9 @@ tags: # Lectures - [x] [[01-intro-to-305]] - [x] [[02-intro-pervasive-and-ubiquitious]] -- [[03-intro-AR-dev]] -- [[04-lens-studio]] +- [x] [[03-intro-AR-dev]] +- [x] [[04-lens-studio]] - [x] [[05-pervasive-ubiquitious-2]] -- [[06-challenges-for-ubicomp-and-intro-to-sensors]] +- [x] [[06-challenges-for-ubicomp-and-intro-to-sensors]] # Info \ No newline at end of file