HexBrain

Nextcloud · Report #1520685

Moderator can enable cam/mic remotely if cam/mic-permission was disabled while user has activated cam/mic

Validstatus
lowseverity
$100bounty
9upvotes
9 Jun 2022disclosed

Summary

Advisory at https://github.com/nextcloud/security-advisories/security/advisories/GHSA-vxpr-hcqq-7fw7

How it was found

Summary:

[add summary of the vulnerability]

Steps To Reproduce:

  1. Create a Call as User A (Moderator)
  2. Add User B to the call
  3. Start the call as User A
  4. User B joins the call and enables the camera
  5. User A removes all permissions for User B, cam and mic are now disabled
  6. User A grants all permissions to User B

--> now mic and cam are enabled remotely, if User B didn't disable it before removing permissions by User B

Used Software Versions:

Nextcloud 23.0.3 spreed-App 13.0.4 nextcloud-spreed-signaling 0.4.0

Impact

A call moderator can remotely enable user webcams, if there were enabled before removing the permissions. This is a big privacy issue.

This report was disclosed publicly on HackerOne and belongs to its author and the program. See the original