--- inforge.net ping statistics ---
1 packets transmitted, 1 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 32.630/32.799/33.073/0.195 ms
From this screen, you only have to type “ping
www.inforge.net
”, excluding
any data, which will change according to situations we cannot determine. Ignore
the initial Dollar symbol ($), this only shows the beginning of a new line.
Keep
have this page available, whenever you get lost in the Operative
System!
In order to know which files and directories are contained in the path we are
in:
$ ls
To access a folder:
$ cd {foldername}
To go back to the previous folder:
$ cd ..
To copy a file:
$ cp {filename} {newfilename}
To move or rename a file:
$ mv {filename} {newfilename}
To create a folder:
$ mkdir {foldername}
To use a text editor (we will use the CTRL+X key combination to close the
editor and Y/N to confirm a possible overwrite action):
$ nano {filename}
And so on. Using the terminal, we will run programs also requiring some
parameters, specified by the - (minus) character: if we wish to know how the ls
command works and its allowed parameters, we must use --help:
$ ls --help
Or, we can use the man tool:
$ man ls
Furthermore, remember that we will use the apt
commands to install new
programs on Debian:
$ apt-get install [packagename]
Although not officially supported by this document, it may be possible to
install the same package on Red Hat-based distros (Fedora, CentOS, etc.) using
the command:
$ yum install [packagename]
or also on Arch Linux-based systems, using the command:
$ pacman -S [packagename]
You’ll always have to launch these and other commands as root
(administrator). In such cases, you should use the prefix:
$ sudo apt-get ...
If the latter is not present, you’ll have to login as root first, using the
command:
$ su
2. Data Traces
Now that
we have installed Debian, itʼs time to learn which traces we may
leave on the net. With “data traces”, we mean all the digital values that can help
revealing our identity somehow. Such traces may identify your computer or your
network adapter, as an evidence of your connection to unsafe networks.
In the worst case scenario, if you use your Internet contract, itʼs quite
possible to expose the first and last name of the
connection owner. There are
many techniques to identify someone who surfed anonymously: later on, weʼll
cover how it can happen and the related countermeasures to avoid that situation.
2.1 MAC Address
MAC (Media Access Control) address is a unique 48bit code assigned by
network adapters manufacturers to their 802.x models; the code is directly
written in the adapter
EEPROM memory and is used for the first authentication
stage to a local network by a network device, such a router, a switch and
whatnot, which will later specify a local IP.
MAC Address is composed by 6 couples of alphanumeric characters,
including numbers from 0 to 9 and letters from A to F (the so called hexadecimal
notation, or base 16) and is represented as follows: ab:bc:cd:de:ef:f0. The first
three sets of numbers (ab:bc:cd) are related
to the manufacturer; check the
IEEE2 standard list for the manufacturers index
[2]
.
Image to connect to a hotel or a public plaza WiFi connection: in this case, a
network structure will manage the DHCP protocol, a system which automatically
assigns the MAC Address a local IP address, allowing you to freely surf the
web! The importance of leaving no traces of a MAC Address is that data is
stored in the network device, and the latter may
not allow to remove logs, not
even to its owner. Furthermore, this MAC Address will be probably shared by
the router/switch with the ISP (Internet Service Provider), which could store it
into their own databases.
2.1.1 Identifying the MAC Address
In order to test the upcoming techniques – allowing us to change our MAC
Address – we need to be able to identify our MAC Address first. To achieve this,
we can use a command line tool available in any operating system (on Windows
itʼs known as Command Prompt, while on Linux and macOS itʼs called
Terminal).
On
Windows, launch the command ipconfig; on macOS and Linux, use
ifconfig; actually, the latter one is going to be deprecated and replaced by the
iproute2 software (evoked using the ip command). Please, keep in mind that
commands have to be run as root, therefore you must use the su command to be
granted with admin access. However, each command may show the
configuration of all the network interface controllers in the computer:
$ ip link show {interface}
en1:
flags=8863
mtu 1500
ether 61:a8:5d:53:b1:b8
inet6 fe80::6aa8:6dff:fe53:b1b8%en1 prefixlen 64 scopeid 0x4
inet 192.168.0.12 netmask 0xffffff00 broadcast 192.168.0.255
nd6 options=1
media: autoselect
status: active
Where {interface} is the name of our network adapter. Usually, eth0
represents the Ethernet adapter, while wlan0 is the WiFi controller. It may
happen that identifiers are different, according to the number of interfaces
installed on your PC. If you wish to verify it, you can see which interfaces are
enabled using the command:
$ ip link show or ip a
We need to identify our MAC Address which is composed by 6 couples of
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