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Questions tagged [x11]

common back end of Unix graphical user interfaces.

55
votes
3answers
17k views

Why has Ubuntu 18.04 moved back to insecure Xorg?

After reading Xorg becomes the default display server again and considering the security risk of xorg, I am wondering why the developers left Wayland. The fact that a few programs do not work on ...
2
votes
1answer
211 views

How do I protect password enteries in Xorg?

I have been doing some reading about security issues with Xorg on Linux, and was surprised to find that you can keylog any GUI application using two shell commands... xinput list xinput test <id ...
7
votes
1answer
344 views

How to mitigate risk of X11 buffer ghosting (palinopsia bug)

The Buffer "Ghosting" Phenomenon It is possible to observe contents of (old and currently used) graphics buffers on a monitor under certain circumstances, posing an information disclosure risk, when ...
4
votes
3answers
2k views

Docker X11 Forwarding Security

I am currently running a Docker container with a program with a GUI forwarded over SSH (using X forwarding over OpenSSH). The virtualized server has X11Forwarding enabled and I can connect to it from ...
2
votes
0answers
123 views

Wayland Partial Encryption for Mouse / Keyboard? (Also X and RDP)

Question What are the best practices for implementing Partial Encryption, to encrypt just the input devices (mouse/keyboard, etc), not the actual video display, during remote desktop sessions using X,...
3
votes
2answers
570 views

Does CVE-2015-5352 work if there is no active X-Server?

My security program shows that one of my servers is vulnerable to CVE-2015-5352. If X-Server is not running (not even installed) is the system really penetrable by that vulnerability?
10
votes
1answer
146 views

GnuPG passphrase entry and X11 sniffing

Each time when I’m entering my passphrase in pinentry-gtk-2, every other X11 app may sniff it, as seen in $ xinput test-xi2 running in the background. What can be done about it? Or do I have to ...
6
votes
2answers
710 views

GUI isolation in X11 when entering Truecrypt password

I have been getting a bit paranoid regarding some of my old TrueCrypt containers. The paranoia has got nothing to do with suspicions regarding TrueCrypt itself (after the shut-down last year), rather ...
8
votes
2answers
4k views

What is considered an acceptable, secure method of remotely connecting to a Linux system?

Given that VNC and X11 were not developed with security in mind, what do people typically see done to remotely connect to a Linux system where a GUI is required. While SSH access alone might be ...
7
votes
1answer
376 views

Shared clipboard on Linux without keylogging, etc. vulnerabilities?

X has some serious security problems, not the least of which is that any program using a given display can log keystrokes from any other program on that display. (This can be demonstrated easily using ...
6
votes
1answer
3k views

Lots of failed outgoing sshd attempts. Am I hacked?

For the last two days I've been seeing lots of lines in my /var/log/auth.log that look like: sshd[xxxxx]: error: connect_to 0.gravatar.com port 80: failed sshd[xxxxx]: error: connect_to 1.gravatar....
22
votes
2answers
15k views

Security Concerns with X11 Forwarding

What are some of the security concerns and reasons either for or against allowing X11 Forwarding. I have generally taken an approach of not allowing it under the blanket guise of security. Recently, ...
25
votes
2answers
3k views

Risks of ssh to an untrusted host? [duplicate]

I use ssh a lot to connect to a variety of servers at my university. The machines are administrated by students, so assume they can't really be trusted;-) What are the risks in making a ssh ...
30
votes
1answer
4k views

Passive and active attacks via X11. Is Wayland any better?

In The Linux Security Circus: On GUI isolation - The Invisible Things Lab's blog, Joanna Rutkowska describes attacks from one X11 app on another and the general problem of the lack of GUI-level ...