Uninstalling Slack for Windows (64-bit), then reinstalling keeps you logged in without authentication
Low
Vulnerability Details
I understand that you are unlikely to consider bugs that require physical machine access, however this issue affected me directly and I was very surprised by it, so I felt it was important to report it in case it was not known.
Steps to reproduce:
1) Install the desktop Slack app for Windows (64-bit).
2) Login to Slack
3) Uninstall Slack
4) Reinstall Slack
Result: You will automatically be logged back in to your account, even though you uninstalled Slack from your computer and did not enter a username/password to login to the fresh Slack installation.
The Slack uninstall process is fully automatic, there is no prompt or indication that there is data left behind. I believe it is reasonable to expect that when uninstalling Slack my session data should have been removed. If I am a user on a shared user account (for example, if I borrowed a computer and I installed Slack, but uninstalled it later), they can take full control of my account after the fact.
When testing this, I could access all of my messages and data, and even access the Slack admin panel for my team that I am an administrator of.
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View on HackerOneReport Stats
- Report ID: 238260
- State: Closed
- Substate: resolved
- Upvotes: 16