Why can I use my cell phone to transfer files when I have blocked all mass storage devices through the Unauthorized Devices table?

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August 27, 2018

Last modified: 11/17/2022, 2:27 pm

Knowledge Base Article Troubleshooting Peripheral Devices Zero Clients

There are 3 ways to transfer data to USB devices.

  • Mass storage devices (flash drives, DVD), all file types
  • Photo Transfer Protocol - PTP - still image capture device class for cameras, (pictures).
  • Media Transport Protocol - MTP - (smartphones), all file types.

 

Scenario

You use the Unauthorized Devices table to block all mass storage devices on a PCoIP device. The USB Unauthorized Devices table is found in the AWI of a PCoIP device (Permissions > USB). You then plug in a Media Transfer Protocol (MTP) device (e.g. cell phone, mp3 player) or camera and discover you are still able to use the device to transfer files. 

 

Cause

  • Media Transport Protocol capable devices are not able to be identified by basic USB descriptors as with Mass Storage Devices, therefore we currently cannot blacklist MTP capable devices like smartphones via our standard USB permissions tables.

 

Fix/Workaround

  • If it is acceptable to permit only a minimal set of devices (eg mouse & keyboard), the zero client white list can be changed from Any, Any to Class, Human Interface Device.

 

Workaround Considerations

  • The impact of only permitting HID devices may block some devices like keyboards with integrated audio if those functions are not separated out behind a hub. 

 

Pertains to:
  • PCoIP Zero Client 4.0.2
  • PCoIP Zero Client 4.0.3
  • PCoIP Zero Client 4.1.0
  • PCoIP Zero Client 4.1.1
  • PCoIP Zero Client 4.1.2
  • PCoIP Zero Client 4.2.0
  • PCoIP Zero Client 4.5.0
  • PCoIP Zero Client 4.5.1
  • PCoIP Zero Client 4.6.0
  • PCoIP Zero Client 4.7.0
  • PCoIP Zero Client 4.7.1
  • PCoIP Zero Client 4.8.0
  • PCoIP Zero Client 4.8.1
  • PCoIP Zero Client 4.8.2
  • PCoIP Zero Client 5.0.0
  • PCoIP Zero Client 5.0.2
  • PCoIP Zero Client 5.1.0
  • PCoIP Zero Client 5.1.1
  • PCoIP Zero Client 5.2.0
  • PCoIP Zero Client 5.2.1
  • PCoIP Zero Client 5.2.2
  • PCoIP Zero Client 5.3.0
  • PCoIP Zero Client 5.4.0
  • PCoIP Zero Client 5.4.1
  • PCoIP Zero Client 5.5.0
  • PCoIP Zero Client 5.5.1
  • PCoIP Zero Client 6.0.0