Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Npcap 1.70 - "Restrict Npcap driver's access to Administrators only --> no interfaces visible on Wireshark #606

Closed
RonnyTNL opened this issue Jun 28, 2022 · 5 comments
Assignees
Labels
bug current Issues with current focus by the core Npcap dev team

Comments

@RonnyTNL
Copy link

After upgrading from 1.60 to 1.70 I can no longer see network interfaces on Wireshark.

  • Win10 21H2
  • Npcap 1.70
  • Wireshark 3.6.6 x64

Reverting back to 1.60 and having all 3 boxes ticked on the installer (restrict/support raw/API compatible) works as expected.
Installing 1.70 with Restrict Npcap driver's access disabled also works and shows interfaces in Wireshark

Seem there is a permission issue introduced between 1.60 and 1.70

@RonnyTNL
Copy link
Author

Just reproduced on a different machine, also Win10 21H2/Wireshark 3.6.6 x64

@dmiller-nmap dmiller-nmap added bug current Issues with current focus by the core Npcap dev team labels Jun 28, 2022
@dmiller-nmap dmiller-nmap self-assigned this Jun 28, 2022
@decopaper
Copy link

I'm having the same issue with this combination:

  • Server 2016
  • Npcap 1.70
  • Nmap 7.92
  • The "Restrict Npcap driver's access to Administrators only" option checked on installation

Reverting to 1.60 also resolves the issue

@fyodor
Copy link
Member

fyodor commented Jun 30, 2022

Thanks for the reports. We've been able to reproduce this issue as well and are planning to resolve it in an Npcap 1.71 release that we hope to make soon.

@dmiller-nmap
Copy link
Contributor

The issue only affects high-integrity processes (e.g. right-click and "Run as Administrator"). Ordinary processes (like running Nmap from an ordinary cmd.exe shell) will launch the NpcapHelper.exe process with UAC elevation, which then shares the Npcap device handle with the lower-integrity parent process. A workaround until the next release, therefore, is to avoid starting Npcap-using processes via the "Run as Administrator" dialog, but rather to let Npcap manage the elevation. This is also preferable generally, since it uses the least privilege necessary.

@RonnyTNL
Copy link
Author

RonnyTNL commented Jul 1, 2022

The issue only affects high-integrity processes (e.g. right-click and "Run as Administrator"). Ordinary processes (like running Nmap from an ordinary cmd.exe shell) will launch the NpcapHelper.exe process with UAC elevation, which then shares the Npcap device handle with the lower-integrity parent process. A workaround until the next release, therefore, is to avoid starting Npcap-using processes via the "Run as Administrator" dialog, but rather to let Npcap manage the elevation. This is also preferable generally, since it uses the least privilege necessary.

That doesn't seem to work when using Wireshark, at least not on my setup, when I start Wireshark as normal user, then I get 3 prompts for the UAC admin credentials when trying to start/use the helper, and then Wireshark still doesn't show interfaces.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
bug current Issues with current focus by the core Npcap dev team
Projects
None yet
Development

No branches or pull requests

4 participants