Difference between revisions of "MAC address spoofing"

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{{i18n|MAC Address Spoofing}}
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[[Category:Networking]]
[[Category:Networking (English)]]
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[[Category:Security]]
[[Category:Security (English)]]
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[[cs:MAC Address Spoofing]]
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[[de:MAC-Adresse abfragen und setzen]]
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[[es:MAC Address Spoofing]]
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[[ru:MAC Address Spoofing]]
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[[zh-CN:MAC Address Spoofing]]
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This article gives several methods to spoof a Media Access Control (MAC) address.
 +
{{Note|In the examples below is assumed the ethernet device is {{ic|enp1s0}}. Use {{ic|ip link}} to check your actual device name, and adjust the examples as necessary}}
  
There are two methods for spoofing a Media Access Control (MAC) address on Arch. Both of them are outlined below.
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== Manually ==
  
{{Warning|Changing network options usually requires special privileges. As such, you will need to be root to do this.}}
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There are two methods for spoofing a MAC address using either {{Pkg|iproute2}} (installed by default) or {{Pkg|macchanger}} (available on the [[official repositories]]).
__TOC__
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== Method 1: macchanger ==
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Both of them are outlined below.
The first method uses [http://www.alobbs.com/macchanger macchanger] (a.k.a., the GNU MAC Changer), written by Alvaro Lopez Ortega. It provides a variety of features such as changing the address to match a certain vendor or completely randomizing it. The first step is to download it from [extra]:
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# pacman -S macchanger
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After this, the MAC can be spoofed with a random address. The syntax is ''macchanger -r <device>''. Standard names for devices are eth0 (for Ethernet) and wlan0 (for wireless), if only one device of each type is connected. For a secondary device, it would be eth1 or wlan1.
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=== Method 1: iproute2 ===
  
Here is an example command for spoofing the MAC address of a device named eth0.
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First, you can check your current MAC address with the command
# macchanger -r eth0
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To randomize all of the address except for the vendor bytes (that is, so that if the MAC address was checked it would still register as being from the same vendor), you would run the command:
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  # ip link show ''interface''
  # macchanger -e eth0
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Finally, to change the MAC address to a specific value, you would run:
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where {{ic|''interface''}} is the name of your [[Network configuration#Network_Interfaces|network interface]].
# macchanger --mac=XX:XX:XX:XX:XX:XX
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+
Where 'XX:XX:XX:XX:XX:XX' is the MAC you wish to change to.
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{{Note|A device cannot be in use (connected in any way or with its interface up) while the MAC address is being changed.}}
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== Method 2: Manual ==
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This method also assumes that your device name is eth0. For clarification, read the second paragraph of Method 1.
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First, you can check your current MAC address with the command:
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$ ip link show eth0
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The section that interests us at the moment is the one that has "link/ether" followed by a 6-byte number. It will probably look something like this:
 
The section that interests us at the moment is the one that has "link/ether" followed by a 6-byte number. It will probably look something like this:
 +
 
  link/ether 00:1d:98:5a:d1:3a
 
  link/ether 00:1d:98:5a:d1:3a
  
The first step to spoofing the MAC address is to bring the network interface down. You must be logged in as root to do this. It can be accomplished with the command:
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The first step to spoofing the MAC address is to bring the network interface down. It can be accomplished with the command:
  $ ip link set dev eth0 down
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 +
  # ip link set dev ''interface'' down
  
 
Next, we actually spoof our MAC. Any hexadecimal value will do, but some networks may be configured to refuse to assign IP addresses to a client whose MAC does not match up with a vendor. Therefore, unless you control the network(s) you are connecting to, it is a good idea to test this out with a known good MAC rather than randomizing it right away.
 
Next, we actually spoof our MAC. Any hexadecimal value will do, but some networks may be configured to refuse to assign IP addresses to a client whose MAC does not match up with a vendor. Therefore, unless you control the network(s) you are connecting to, it is a good idea to test this out with a known good MAC rather than randomizing it right away.
  
 
To change the MAC, we need to run the command:
 
To change the MAC, we need to run the command:
  $ ip link set dev eth0 address XX:XX:XX:XX:XX:XX
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 +
  # ip link set dev ''interface'' address XX:XX:XX:XX:XX:XX
  
 
Where any 6-byte value will suffice for 'XX:XX:XX:XX:XX:XX'.
 
Where any 6-byte value will suffice for 'XX:XX:XX:XX:XX:XX'.
  
 
The final step is to bring the network interface back up. This can be accomplished by running the command:
 
The final step is to bring the network interface back up. This can be accomplished by running the command:
$ ip link set dev eth0 up
 
  
If you want to verify that your MAC has been spoofed, simply run 'ip link show eth0' again and check the value for 'link/ether'. If it worked, 'link/ether' should be whatever address you decided to change it to.
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# ip link set dev ''interface'' up
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 +
If you want to verify that your MAC has been spoofed, simply run {{ic|ip link show ''interface''}} again and check the value for 'link/ether'. If it worked, 'link/ether' should be whatever address you decided to change it to.
 +
 
 +
=== Method 2: macchanger ===
 +
 
 +
Another method uses {{Pkg|macchanger}} (a.k.a., the GNU MAC Changer). It provides a variety of features such as changing the address to match a certain vendor or completely randomizing it.
 +
 
 +
[[Pacman|Install]] the package {{Pkg|macchanger}} from the [[official repositories]].
 +
 
 +
The spoofing is done on per-interface basis, specify [[Network configuration#Network_Interfaces|network interface]] name as {{ic|''interface''}} in each of the following commands.
 +
 
 +
The MAC address can be spoofed with a fully random address:
 +
 
 +
# macchanger -r ''interface''
 +
 
 +
To randomize all of the address except for the vendor bytes (that is, so that if the MAC address was checked it would still register as being from the same vendor), you would run the command:
 +
 
 +
# macchanger -e ''interface''
 +
 
 +
To change the MAC address to a specific value, you would run:
 +
 
 +
# macchanger --mac=XX:XX:XX:XX:XX:XX ''interface''
 +
 
 +
Where {{ic|XX:XX:XX:XX:XX:XX}} is the MAC you wish to change to.
 +
 
 +
Finally, to return the MAC address to its original, permanent hardware value:
 +
 
 +
# macchanger -p ''interface''
 +
 
 +
{{Note|A device cannot be in use (connected in any way or with its interface up) while the MAC address is being changed.}}
 +
 
 +
== Automatically ==
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 +
=== Systemd unit ===
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 +
This example uses [[#Method 1: iproute2]].
 +
 
 +
{{hc|/etc/systemd/system/macspoof@.service|<nowiki>
 +
[Unit]
 +
Description=MAC address change %I
 +
Before=dhcpcd@%i.service
 +
 
 +
[Service]
 +
Type=oneshot
 +
ExecStart=/usr/bin/ip link set dev %i address 36:aa:88:c8:75:3a
 +
ExecStart=/usr/bin/ip link set dev %i up
 +
 
 +
[Install]
 +
WantedBy=network.target
 +
</nowiki>}}
 +
 
 +
You may have to edit this file if you do not use [[dhcpcd]].
 +
 
 +
=== Systemd unit using random address ===
 +
 
 +
This example uses [[#Method 2: macchanger]], so make sure that {{Pkg|macchanger}} is [[Pacman|installed]].
  
== Spoofing MAC with netcfg ==
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{{hc|/etc/systemd/system/macchanger@.service|<nowiki>
Put the following line in your netcfg profile to have it spoof your MAC address when its started
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[Unit]
PRE_UP='macchanger -e wlan0'
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Description=Macchanger service for %I
You may have to replace wlan0 with your interface name.
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Documentation=man:macchanger(1)
  
== Spoofing MAC On Boot ==
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[Service]
You will notice with the above methods that upon reboot, your MAC will return to its initial default value. To set your MAC on boot, create the file {{ic|/etc/rc.d/functions.d/macspoof}} with the following content:
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ExecStart=/usr/bin/macchanger -e %I
 +
Type=oneshot
  
<pre>
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[Install]
spoof_mac() {
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WantedBy=multi-user.target
ip link set dev eth0 address XX:XX:XX:XX:XX:XX
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</nowiki>}}
}
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add_hook sysinit_end spoof_mac
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== See also ==
</pre>
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== Links and References ==
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* [https://github.com/alobbs/macchanger Macchanger GitHub page
* [http://www.alobbs.com/macchanger macchanger] project page.
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* [http://www.debianadmin.com/change-your-network-card-mac-media-access-control-address.html Article on DebianAdmin] with more macchanger options
* [http://www.debianadmin.com/change-your-network-card-mac-media-access-control-address.html Article on DebianAdmin] with more macchanger options.
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Revision as of 12:22, 15 February 2014

This article gives several methods to spoof a Media Access Control (MAC) address.

Note: In the examples below is assumed the ethernet device is enp1s0. Use ip link to check your actual device name, and adjust the examples as necessary

Manually

There are two methods for spoofing a MAC address using either iproute2 (installed by default) or macchanger (available on the official repositories).

Both of them are outlined below.

Method 1: iproute2

First, you can check your current MAC address with the command

# ip link show interface

where interface is the name of your network interface.

The section that interests us at the moment is the one that has "link/ether" followed by a 6-byte number. It will probably look something like this:

link/ether 00:1d:98:5a:d1:3a

The first step to spoofing the MAC address is to bring the network interface down. It can be accomplished with the command:

# ip link set dev interface down

Next, we actually spoof our MAC. Any hexadecimal value will do, but some networks may be configured to refuse to assign IP addresses to a client whose MAC does not match up with a vendor. Therefore, unless you control the network(s) you are connecting to, it is a good idea to test this out with a known good MAC rather than randomizing it right away.

To change the MAC, we need to run the command:

# ip link set dev interface address XX:XX:XX:XX:XX:XX

Where any 6-byte value will suffice for 'XX:XX:XX:XX:XX:XX'.

The final step is to bring the network interface back up. This can be accomplished by running the command:

# ip link set dev interface up

If you want to verify that your MAC has been spoofed, simply run ip link show interface again and check the value for 'link/ether'. If it worked, 'link/ether' should be whatever address you decided to change it to.

Method 2: macchanger

Another method uses macchanger (a.k.a., the GNU MAC Changer). It provides a variety of features such as changing the address to match a certain vendor or completely randomizing it.

Install the package macchanger from the official repositories.

The spoofing is done on per-interface basis, specify network interface name as interface in each of the following commands.

The MAC address can be spoofed with a fully random address:

# macchanger -r interface

To randomize all of the address except for the vendor bytes (that is, so that if the MAC address was checked it would still register as being from the same vendor), you would run the command:

# macchanger -e interface

To change the MAC address to a specific value, you would run:

# macchanger --mac=XX:XX:XX:XX:XX:XX interface

Where XX:XX:XX:XX:XX:XX is the MAC you wish to change to.

Finally, to return the MAC address to its original, permanent hardware value:

# macchanger -p interface
Note: A device cannot be in use (connected in any way or with its interface up) while the MAC address is being changed.

Automatically

Systemd unit

This example uses #Method 1: iproute2.

/etc/systemd/system/macspoof@.service
[Unit]
Description=MAC address change %I
Before=dhcpcd@%i.service

[Service]
Type=oneshot
ExecStart=/usr/bin/ip link set dev %i address 36:aa:88:c8:75:3a
ExecStart=/usr/bin/ip link set dev %i up

[Install]
WantedBy=network.target

You may have to edit this file if you do not use dhcpcd.

Systemd unit using random address

This example uses #Method 2: macchanger, so make sure that macchanger is installed.

/etc/systemd/system/macchanger@.service
[Unit]
Description=Macchanger service for %I
Documentation=man:macchanger(1)

[Service]
ExecStart=/usr/bin/macchanger -e %I
Type=oneshot

[Install]
WantedBy=multi-user.target

See also