--- tags: ccdc --- # UAA CCDC Quick cheat sheet ## Backup configs - Linux ``` bash gzip -rf --best -c /path/to/folder > folder.gz # create backup archive of folder gzip --best -c /path/to/file > file.gz # create backup archive of file gunzip file.gz # unzip folder # if gzip is not available tar cxzf /path/to/folder/ file.tar.gz # create backup archive of file or folder tar -xf file.tar.gz # uncompress file rsync -P archiveFile user@ip:/path/to/remote/store/ # move file to remote machine ``` ## Audit Users ``` bash passwd -l root # Changes/locks ‘root’ pass getent passwd 0 # should only be one, root getent group root admin sudo wheel # list all root and admin getent passwd | cut -d : -f 1 | xargs groups # List all users, with groups they’re in deluser -rf <usr> # Delete gpasswd -d <usr> <group> # remove <usr> group usermod -aG <group> <usr> # add <usr> group ``` ### Check sudoers files ``` bash visudo # edit/ # Expected entries: # root ALL=(ALL:ALL) ALL # %wheel ALL=(ALL) ALL # %sudo ALL=(ALL) ALL ``` ## Check ssh config Config at: /etc/ssh/sshd_config Change to: PermitRootLogin no SSH: (Ubuntu) Service ssh restart (Centos / Fedora) Service sshd restart ## Firewall ```bash ufw allow <ports> # do for all ports allowed ufw default deny # set default rule ufw enable # start firewall ufw status numbered # check rules ufw delete <num> # delete bad rules ``` ## Check Sources and Update schedule ### apt GUI: Software & Updates Config: /etc/apt/sources.list and /etc/apt/sources.list.d/ ``` bash apt update # refresh sources apt upgrade -y # install updates apt install <pkg> # install program apt remove --purge <pkg> # uninstall program apt list --installed # view installed programs ``` ### yum Config: /etc/yum.repos.d/ ``` bash # Every yum command refreshes the sources yum update # update packages yum install <pkg> # install package yum remove <pkg> # uninstall package ```