Questions tagged [x11]

common back end of Unix graphical user interfaces.

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X11 forwarding to another user. How it's possible?

I would like to understand how the following problem is technically possible: In my company, we have a machine which I and several colleagues connect to. I regularly use x11 forwarding when I connect ...
Hantlowt's user avatar
19 votes
5 answers

Is it really safe to pass sensitive data to another script via stdin, compared to passing via arguments (Linux)

Yes, the transfer to the script via arguments is visible through ps -ax, /proc/<pid>/cmdline etc., BUT if someone has already gained access to your account from the outside (e.g. by hacking your ...
NewLinux's user avatar
  • 675
2 votes
1 answer

Is X11 dangerous?

I'm new to Linux and want to understand if X11 is really as dangerous as they say on the Internet? I will explain how I understand this. Any application launched from under the current user has ...
Dstart's user avatar
  • 131
52 votes
3 answers

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 ...
ar2015's user avatar
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3 votes
1 answer

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 ...
Caleb Reister's user avatar
8 votes
1 answer

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 ...
user avatar
4 votes
3 answers

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 ...
Mythical Juggernaut's user avatar
2 votes
0 answers

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,...
elika kohen's user avatar
3 votes
2 answers

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?
Harrys Kavan's user avatar
10 votes
1 answer

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 ...
Michal Rus's user avatar
8 votes
2 answers

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 ...
shivams's user avatar
  • 221
9 votes
2 answers

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 ...
appsecguy's user avatar
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8 votes
1 answer

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 ...
DanL4096's user avatar
  • 307
6 votes
1 answer

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 port 80: failed sshd[xxxxx]: error: connect_to 1.gravatar....
Beau's user avatar
  • 163
45 votes
3 answers

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, ...
John's user avatar
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29 votes
2 answers

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 ...
bud's user avatar
  • 291
40 votes
1 answer

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 ...
nealmcb's user avatar
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