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Error permissions on usb device on Ubuntu 20.04.4 LTs

asked 2022-05-01 17:53:39 +0000

eduardo74 gravatar image

Im on ubuntu 20.04 and im facing permissions problem to capture traffic from usb device. Ive made all the things they told me, im on wireshark group and made reconfigure many times to allow non superusers be able to capture traffic.

Any help would be apreciated

Error: The capture session could not be initiated on interface 'usbmon1' (You don't have permission to capture on that device). Please check to make sure you have sufficient permissions.

On Debian and Debian derivatives such as Ubuntu, if you have installed Wireshark from a package, try running

sudo dpkg-reconfigure wireshark-common

selecting "<yes>" in response to the question

Should non-superusers be able to capture packets?

adding yourself to the "wireshark" group by running

sudo usermod -a -G wireshark {your username}

and then logging out and logging back in again.

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answered 2022-05-01 18:21:03 +0000

Chuckc gravatar image

updated 2022-05-01 18:22:07 +0000

There is an extra step for the USB devices:
USB capture setup: Linux

To give regular users privileges, make the usbmonX device(s) readable:

sudo setfacl -m u:$USER:r /dev/usbmon*

(Sniff usb with non-root user under Ubuntu 18.04)

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But every time i reboot i have to execute this possible to make it "forever" ? Thanks

eduardo74 gravatar imageeduardo74 ( 2022-05-14 18:43:08 +0000 )edit

The device files (/dev/usbmon*) don't exist until the usbmon kernel module is loaded.
The kernel docs (usbmon) mention compiling it into the kernel but that's not something covered here.
If you look around, other have encountered this with setfacl and created startup scripts to load the kernel module and set the permissions.
Here is a different method that set group information on the files: Capturing USB Serial data using wireshark

Chuckc gravatar imageChuckc ( 2022-05-15 16:20:38 +0000 )edit

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Asked: 2022-05-01 17:53:39 +0000

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Last updated: May 01 '22