Difference between revisions of "MAC address spoofing"

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[[Category:Networking (English)]]
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[[Category:Networking]]
[[Category:HOWTOs (English)]]
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[[Category:Security]]
{{i18n|MAC Address Spoofing}}
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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|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]]).
  
== Introduction ==
+
Both of them are outlined below.
There are two methods for spoofing a Media Access Control (MAC) address on Arch. Both of them are outlined below.
+
  
== Method 1: macchanger ==
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=== Method 1: iproute2 ===
The first method uses [http://www.alobbs.com/macchanger macchanger], known in full as 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]:
+
First, you can check your current MAC address with the command:
$ 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.
+
{{bc|# ip link show eth0}}
  
Here is an example command for spoofing the MAC address of a device named eth0. NOTE: This must be done as root.
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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:
$ macchanger -r eth0
+
  
To randomize all of the MAC 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:
+
{{bc|link/ether 00:1d:98:5a:d1:3a}}
$ macchanger -e eth0
+
  
Finally, to change the MAC address to a specific value, you would run:
+
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:
$ macchanger --mac=XX:XX:XX:XX:XX:XX
+
  
Where 'XX:XX:XX:XX:XX:XX' is the MAC you wish to change to.
+
{{bc|# ip link set dev eth0 down}}
  
NOTE: As well, a device cannot be in use (connected in any way or with its interface up) while the MAC address is being changed.
+
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:
  
== Method 2: Manual ==
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{{bc|# ip link set dev eth0 address XX:XX:XX:XX:XX:XX}}
  
This method also assumes that your device name is eth0. For clarification, read the second paragraph of Method 1.
+
Where any 6-byte value will suffice for 'XX:XX:XX:XX:XX:XX'.
  
First, you can check your current MAC address with the command:
+
The final step is to bring the network interface back up. This can be accomplished by running the command:
$ ifconfig eth0
+
  
The section that interests us at the moment is the one that has "HWaddr" followed by a 6-byte number. It will probably look something like this:
+
{{bc|# ip link set dev eth0 up}}
HWaddr 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:
+
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.
$ ifconfig 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 at first.
+
=== Method 2: macchanger ===
  
To change the MAC, we need to run the command:
+
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.
$ ifconfig eth0 hw ether XX:XX:XX:XX:XX:XX
+
  
Where any 6-byte value will suffice for 'XX:XX:XX:XX:XX:XX'.
+
[[Pacman|Install]] the package {{Pkg|macchanger}} from the [[Official Repositories]].
  
The final step is to bring the network interface back up. This can be accomplished by running the command:
+
After this, the MAC can be spoofed with a random address. The syntax is {{ic|macchanger -r ''<device>''}}.
$ ifconfig eth0 up
+
 
 +
Here is an example command for spoofing the MAC address of a device named 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:
 +
 
 +
{{bc|# macchanger -e eth0}}
 +
 
 +
To change the MAC address to a specific value, you would run:
 +
 
 +
{{bc|1=# macchanger --mac=XX:XX:XX:XX:XX:XX eth0}}
 +
 
 +
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:
 +
 
 +
{{bc|# 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 ===
 +
[[Pacman|Install]] the package {{Pkg|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:
 +
 
 +
{{bc|1=PRE_UP='macchanger -e wlan0'}}
 +
 
 +
You may have to replace {{ic|wlan0}} with your interface name.
 +
 
 +
=== 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
 +
 
 +
[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.
  
If you want to verify that your MAC has been spoofed, simply run 'ifconfig eth0' again and check the value for HWaddr. If it worked, HWaddr should be whatever address you decided to change it to.
+
== See also ==
  
== External Links ==
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* [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.]
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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.

Revision as of 11:05, 6 April 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.

See also