System Information

Since we will be working with many different Linux systems, we need to learn the structure and the information about the system, its processes, network configurations, users, directories, user settings, and the corresponding parameters.

Here is a list of the necessary tools that will help us get the above information. Most of them are installed by default.

Command	Description
whoami	Displays current username.
id	Returns users identity
hostname	Sets or prints the name of current host system.
uname	Prints operating system name.
pwd	Returns working directory name.
ifconfig	The ifconfig utility is used to assign or to view an address to a network interface and/or configure network interface parameters.
ip	Ip is a utility to show or manipulate routing, network devices, interfaces and tunnels.
netstat	Shows network status.
ss	Another utility to investigate sockets.
ps	Shows process status.
who	Displays who is logged in.
env	Prints environment or sets and executes command.
lsblk	Lists block devices.
lsusb	Lists USB devices
lsof	Lists opened files.
lspci	Lists PCI devices.

Let us look at a few examples.

Whoami

anir0y@arishti[/lab]$ whoami

cry0l1t3

Id

anir0y@arishti[/lab]$ id
uid=1000(cry0l1t3) gid=1000(cry0l1t3) groups=1000(cry0l1t3),1337(hackthebox),4(adm),24(cdrom),27(sudo),30(dip),46(plugdev),116(lpadmin),126(sambashare)

Uname

anir0y@arishti[/lab]$ uname -a

Linux box 4.15.0-99-generic #100-Ubuntu SMP Wed Apr 22 20:32:56 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

It is highly recommended to study the commands and understand what they are for and what information they can provide. This information is not only used for working with Linux. However, it will also be used later to discover vulnerabilities and misconfigurations on the Linux system that may contribute to privilege escalation.