Difference between revisions of "MAC address spoofing"

From ArchWiki
Jump to: navigation, search
(proper way to do mac spoofing on boot (old way involved changing system files))
(added another unit)
(27 intermediate revisions by 9 users not shown)
Line 1: Line 1:
{{i18n|MAC Address Spoofing}}
+
[[Category:Networking]]
[[Category:Networking (English)]]
+
[[Category:Security]]
[[Category:Security (English)]]
+
[[cs:MAC Address Spoofing]]
 +
[[de:MAC-Adresse abfragen und setzen]]
 +
[[es:MAC Address Spoofing]]
 +
[[ru:MAC Address Spoofing]]
 +
[[zh-CN:MAC Address Spoofing]]
 +
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|eth0}}. Use {{ic|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 {{Pkg|iproute2}} (installed by default) or {{Pkg|macchanger}} (available on the [[Official Repositories]]).
  
There are two methods for spoofing a Media Access Control (MAC) address on Arch. Both of them are outlined below.
+
Both of them are outlined below.
  
{{Warning|Changing network options usually requires special privileges. As such, you will need to be root to do this.}}
+
=== Method 1: iproute2 ===
__TOC__
+
First, you can check your current MAC address with the command:
 +
 
 +
{{bc|# ip link show eth0}}
 +
 
 +
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:
 +
 
 +
{{bc|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:
 +
 
 +
{{bc|# ip link set dev eth0 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:
 +
 
 +
{{bc|# ip link set dev eth0 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:
 +
 
 +
{{bc|# ip link set dev eth0 up}}
 +
 
 +
If you want to verify that your MAC has been spoofed, simply run {{ic|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.
 +
 
 +
=== 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.
  
== Method 1: macchanger ==
+
[[Pacman|Install]] the package {{Pkg|macchanger}} from the [[Official Repositories]].
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]:
+
# pacman -S macchanger
+
  
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.  
+
After this, the MAC can be spoofed with a random address. The syntax is {{ic|macchanger -r ''<device>''}}.  
  
 
Here is an example command for spoofing the MAC address of a device named eth0.
 
Here is an example command for spoofing the MAC address of a device named eth0.
# macchanger -r eth0
+
 
 +
{{bc|# macchanger -r eth0}}
  
 
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:
 
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 eth0
 
  
Finally, to change the MAC address to a specific value, you would run:
+
{{bc|# macchanger -e eth0}}
# macchanger --mac=XX:XX:XX:XX:XX:XX
+
  
Where 'XX:XX:XX:XX:XX:XX' is the MAC you wish to change to.
+
To change the MAC address to a specific value, you would run:
  
{{Note|A device cannot be in use (connected in any way or with its interface up) while the MAC address is being changed.}}
+
{{bc|1=# macchanger --mac=XX:XX:XX:XX:XX:XX eth0}}
  
== Method 2: Manual ==
+
Where {{ic|XX:XX:XX:XX:XX:XX}} is the MAC you wish to change to.
  
This method also assumes that your device name is eth0. For clarification, read the second paragraph of Method 1.
+
Finally, to return the MAC address to its original, permanent hardware value:
  
First, you can check your current MAC address with the command:
+
{{bc|# macchanger -p eth0}}
$ ip link show eth0
+
  
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:
+
{{Note|A device cannot be in use (connected in any way or with its interface up) while the MAC address is being changed.}}
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:
+
== Automatically ==
$ ip link set dev eth0 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.
+
=== netcfg ===
 +
[[Pacman|Install]] the package {{Pkg|macchanger}} from the [[Official Repositories]]. Read the [[#Method 2: macchanger]] method for more information.
  
To change the MAC, we need to run the command:
+
Put the following line in your [[netcfg]] profile to have it spoof your MAC address when it's started:
$ ip link set dev eth0 address XX:XX:XX:XX:XX:XX
+
  
Where any 6-byte value will suffice for 'XX:XX:XX:XX:XX:XX'.
+
{{bc|1=PRE_UP='macchanger -e wlan0'}}
  
The final step is to bring the network interface back up. This can be accomplished by running the command:
+
You may have to replace {{ic|wlan0}} with your interface name.
$ ip link set dev eth0 up
+
 
 +
=== Systemd unit ===
 +
 
 +
{{hc|/etc/systemd/system/macspoof@.service|
 +
[Unit]
 +
Description&#61;MAC address change %I
 +
Before&#61;dhcpcd@%i.service
 +
 
 +
[Service]
 +
Type&#61;oneshot
 +
ExecStart&#61;/usr/sbin/ip link set dev %i address 36:aa:88:c8:75:3a
 +
ExecStart&#61;/usr/sbin/ip link set dev %i 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.
+
[Install]
 +
WantedBy&#61;network.target}}
 +
You may have to edit this file if you do not use dhcpcd.
 +
{{Note|This works without netcfg. If you are using netcfg, see above.}}
  
== Spoofing MAC with netcfg ==
+
=== Systemd unit using random address ===
Put the following line in your netcfg profile to have it spoof your MAC address when its started
+
A unit featuring random address, which requires macchanger:
PRE_UP='macchanger -e wlan0'
+
{{hc|/etc/systemd/system/macchanger@.service|
You may have to replace wlan0 with your interface name.
+
[Unit]
 +
Description&#61;Macchanger service for %I
 +
Documentation&#61;man:macchanger(1)
  
== Spoofing MAC On Boot ==
+
[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 /etc/rc.d/functions.d/macspoof with the following content:
+
ExecStart&#61;/usr/bin/macchanger -e %I
 +
Type&#61;oneshot
  
<pre>
+
[Install]
spoof_mac() {
+
WantedBy&#61;multi-user.target}}
ip link set dev eth0 address XX:XX:XX:XX:XX:XX
+
}
+
  
add_hook sysinit_end spoof_mac
+
== See also ==
</pre>
+
  
== Links and References ==
+
* [http://www.alobbs.com/macchanger macchanger project page
* [http://www.alobbs.com/macchanger macchanger] project page.
+
 
* [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.

Revision as of 20:48, 8 May 2013

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

Note: In the examples below is assumed the ethernet device is eth0. 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 eth0

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. You must be logged in as root to do this. It can be accomplished with the command:

# ip link set dev eth0 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 eth0 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 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.

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.

After this, the MAC can be spoofed with a random address. The syntax is macchanger -r <device>.

Here is an example command for spoofing the MAC address of a device named eth0.

# macchanger -r eth0

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 eth0

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

# macchanger --mac=XX:XX:XX:XX:XX:XX eth0

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 eth0
Note: A device cannot be in use (connected in any way or with its interface up) while the MAC address is being changed.

Automatically

netcfg

Install the package macchanger from the Official Repositories. Read the #Method 2: macchanger method for more information.

Put the following line in your netcfg profile to have it spoof your MAC address when it's started:

PRE_UP='macchanger -e wlan0'

You may have to replace wlan0 with your interface name.

Systemd unit

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

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

[Install]
WantedBy=network.target

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

Note: This works without netcfg. If you are using netcfg, see above.

Systemd unit using random address

A unit featuring random address, which requires macchanger:

/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