Linux Basics for Hackers Flashcards

Flashcards from the book 'Linux Basics for Hackers'

Binaries

Files that can be executed, similar to executables in Windows.

Case sensitivity

Unlike Windows, Linux is case sensitive.

Directory

Same as a folder in Windows.

Home

Each user has their own directory, which is generally where files you create will be saved by default.

Kali Linux

A distribution of Linux specifically designed for penetration testing, with hundreds of tools preinstalled.

root

An administrator or superuser account that can do nearly anything on the system.

Script

A series of commands run in an interpretive environment that converts each line to source code.

Shell

An environment and interpreter for running commands in Linux.

Terminal

A command line interface (CLI).

pwd

Returns your location within the directory structure.

whoami

Displays which user you're logged in as.

cd

Changes directories from the terminal.

ls

Lists the contents of a directory.

--help

Displays available help for a command, application, or utility.

man

Displays a manual page for a command, utility, or application.

locate

Searches the entire filesystem and locate every occurrence of a specified keyword.

whereis

Locates a binary file, also returning its source and man page if available.

which

Returns the location of binaries in the PATH variable in Linux.

find

Most powerful and flexible of the searching utilities, capable of searching for a number of different parameters.

grep

Filter searches for particular keywords.

cat

Used for displaying the contents of a file, can also create small files.

touch

Was originally developed so a user could simply touch a file to change details, such as the date created/modified, will also create files by default.

mkdir

Command for creating a directory in Linux.

Cp

Creates a duplicate of the file in the new location and leaves the old one in place.

Mv

Command intended solely for renaming a file.

Rm

Removes a file.

Rmdir

Removes a directory.

head

Displays the beginning of a file.

tail

Displays the last lines of a file.

nl

Displays a file with line numbers.

Sed

Lets you search for occurences of a word or text pattern and then perform some action on it.

Cat

Displays files and creates small files, has limitations when displaying large files.

More

Displays a page of a file at a time and lets you page down through it with the ENTER key.

Less

Command same as more, but with additional functionality. Can scroll through a file at your leisure, as well as filter it for terms.

ifconfig

Tools for examining and interacting with active network interfaces.

Iwconfig

Gathers crucial information for wireless hacking (IP address, MAC address, mode, and more).

Permissions

Assigns a particular level of permission for the different identities using it.

Granting the Root User’s Group Permissions SGID

With, an SGID bit set, someone without execute permission can execute a file if the owner belongs to the group that has permission to execute that file.

The Outmoded Sticky Bit

This allows a user to delete or rename files within that directory.

Special Permissions, Privilege Escalation, and the Hacker

Here, a regular user gains root or sysadmin privileges and the associated permissions.

Updating Packages

Software repositories will be periodically updated with new software or new versions of existing software.

Upgrading Packages

Upgrades the existing packages on your system.

Software download methods

Software package managers (like apt), GUI-based installers, and git clones are the most common and crucial methods for an aspiring hacker to know.

Rsyslog logging rules

Each line is a separate logging rule that says what messages are logged and where they're logged to.

change nameserver DNS

This command echoes the string nameserver 8.8.8.8 and redirects it (>) to the file /etc/resolv.conf, replacing the current content.

zombie process

A process that exhibits this type of behavior is often referred to as a zombie process.

dd

It creates file name physical copies of storage devices without the filesystem or other logical structures, allowing you to recover such artifacts as deleted files.

what in this world is Variable?

The way it works is that the variable name points to data stored in a memory location, which may contain any kind of value, such as an integer, real number, string, floating-point number, Boolean (true or false statement), list, or dictionary.