tightvncserver - Displaying Grey Screen on Kali-Linux upon VNC Connection

Question

PROBLEM: Upon connecting to my tightvncerver on port 5901, I am greeted with a grey screen with an 'X' for a cursor.

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Hardware: Raspberry Pi 3

Operating System: Kali Linux 0.6 Raspberry Pi 3 w/ Nexmon

Note: I am using xfce as the display manager on this machine.

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STEPS:

I start tightvncserver using the following command:

vncserver :1

Which outputs:

New 'X' desktop is kali:1

Starting applications specified in /root/.vnc/xstartup
Log file is /root/.vnc/kali:1.log

Then I attempt to connect to my VNC server as seen below:

BAM grey screen! Why?!

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/root/.vnc/xstartup:

#!/bin/sh

xrdb $HOME/.Xresources
xsetroot -solid grey
#x-terminal-emulator -geometry 80x24+10+10 -ls -title "$VNCDESKTOP Desktop" &
#x-window-manager &
# Fix to make GNOME work
export XKL_XMODMAP_DISABLE=1
/etc/X11/Xsession

/root/.vnc/kali:\1.log:

23/01/17 12:46:52 Xvnc version TightVNC-1.3.9
23/01/17 12:46:52 Copyright (C) 2000-2007 TightVNC Group
23/01/17 12:46:52 Copyright (C) 1999 AT&T Laboratories Cambridge
23/01/17 12:46:52 All Rights Reserved.
23/01/17 12:46:52 See http://www.tightvnc.com/ for information on TightVNC
23/01/17 12:46:52 Desktop name 'X' (kali:1)
23/01/17 12:46:52 Protocol versions supported: 3.3, 3.7, 3.8, 3.7t, 3.8t
23/01/17 12:46:52 Listening for VNC connections on TCP port 5901

23/01/17 12:59:57 Got connection from client 172.24.1.135
23/01/17 12:59:57 Using protocol version 3.8
23/01/17 13:00:02 Full-control authentication passed by 172.24.1.135
23/01/17 13:00:02 rfbProcessClientNormalMessage: ignoring unknown encoding 16
23/01/17 13:00:02 rfbProcessClientNormalMessage: ignoring unknown encoding 22
23/01/17 13:00:02 rfbProcessClientNormalMessage: ignoring unknown encoding 21
23/01/17 13:00:02 rfbProcessClientNormalMessage: ignoring unknown encoding 15
23/01/17 13:00:02 Using zlib encoding for client 172.24.1.135
23/01/17 13:00:02 rfbProcessClientNormalMessage: ignoring unknown encoding -314
23/01/17 13:00:02 Enabling full-color cursor updates for client 172.24.1.135
23/01/17 13:00:02 rfbProcessClientNormalMessage: ignoring unknown encoding -223
23/01/17 13:00:02 Pixel format for client 172.24.1.135:
23/01/17 13:00:02   8 bpp, depth 8
23/01/17 13:00:02   uses a colour map (not true colour).
23/01/17 13:00:02 Using raw encoding for client 172.24.1.135
23/01/17 13:00:02 rfbProcessClientNormalMessage: ignoring unknown encoding 22
23/01/17 13:00:02 rfbProcessClientNormalMessage: ignoring unknown encoding 21
23/01/17 13:00:02 rfbProcessClientNormalMessage: ignoring unknown encoding 16
23/01/17 13:00:02 rfbProcessClientNormalMessage: ignoring unknown encoding 15
23/01/17 13:00:02 rfbProcessClientNormalMessage: ignoring unknown encoding -314
23/01/17 13:00:02 Enabling full-color cursor updates for client 172.24.1.135
23/01/17 13:00:02 rfbProcessClientNormalMessage: ignoring unknown encoding -223
23/01/17 13:00:02 rfbProcessClientNormalMessage: ignoring unknown encoding 15
23/01/17 13:00:02 Using hextile encoding for client 172.24.1.135
23/01/17 13:00:02 rfbProcessClientNormalMessage: ignoring unknown encoding 22
23/01/17 13:00:02 rfbProcessClientNormalMessage: ignoring unknown encoding 21
23/01/17 13:00:02 rfbProcessClientNormalMessage: ignoring unknown encoding 16
23/01/17 13:00:02 rfbProcessClientNormalMessage: ignoring unknown encoding -314
23/01/17 13:00:02 Enabling full-color cursor updates for client 172.24.1.135
23/01/17 13:00:02 rfbProcessClientNormalMessage: ignoring unknown encoding -223
23/01/17 13:00:02 Pixel format for client 172.24.1.135:
23/01/17 13:00:02   32 bpp, depth 24, little endian
23/01/17 13:00:02   true colour: max r 255 g 255 b 255, shift r 16 g 8 b 0
23/01/17 13:00:02   no translation needed
23/01/17 13:00:08 Client 172.24.1.135 gone
23/01/17 13:00:08 Statistics:
23/01/17 13:00:08   key events received 0, pointer events 158
23/01/17 13:00:08   framebuffer updates 3, rectangles 29, bytes 22762
23/01/17 13:00:08     cursor shape updates 3, bytes 1668
23/01/17 13:00:08     raw rectangles 1, bytes 16396
23/01/17 13:00:08     hextile rectangles 1, bytes 3088
23/01/17 13:00:08     zlib rectangles 24, bytes 1610
23/01/17 13:00:08   raw bytes equivalent 3948580, compression ratio 187.189722

Answer 1

Doing some additional research, I have come across an additional answer that has solved this problem for me in the past.

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⚠️ Please note the below information:

This solution works with any of the Raspberry Pi Kali ARM-based images.

That is because these images come with TightVNC rather than TigerVNC installed.

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Below is my step-by-step solution:

Solution:

We are going to modify the contents of ~/.vnc/xstartup, so it will be a good idea to back up its contents first.

cp ~/.vnc/xstartup ~/.vnc/xstartup.bak

Now we must modify ~/.vnc/xstartup to have the following content:

#!/bin/sh
unset SESSION_MANAGER
unset DBUS_SESSION_BUS_ADDRESS
startxfce4 &

[ -x /etc/vnc/xstartup ] && exec /etc/vnc/xstartup
[ -r $HOME/.Xresources ] && xrdb $HOME/.Xresources
xsetroot -solid grey
vncconfig -iconic &

Now, save and exit the file. Then, reboot the Pi and start tightvncserver. The grey screen should be gone and you should be presented with your xfce4 desktop.

Answer 2

Apparently, Kali Linux 0.6 Raspberry Pi 3 w/ Nexmon contains older packages. Once issuing the command apt-get update && apt-get -y upgrade && apt-get -y dist-upgrade tightvncserver gets replaced by tigervncserver. Thus, TightVNC isn't part of this image of Kali Linux. TigerVNC is a fork that is supported by the standard Kali Linux repositories.

I managed to figure out a pretty good alternative to TightVNC and TigerVNC. Below is my expanded solution.

Solution:

I would recommend using x11vnc as it provides the actual desktop experience rather than a virtual one.

To install x11vnc enter the following command:

apt-get update && apt-get install -y x11vnc

If you experience that the framebuffer size is too small, then to change it by doing the following:

1. Locate /boot/config.txt and open it using nano or vim

(Note: If the file /boot/config.txt does not exist, safely power-off the Pi using the command, poweroff and take the Micro-SD card out and plug it into a laptop or desktop computer. When the Micro-SD card mounts, open it. The config.txt file should be on the root of the mounted Micro-SD card).

2. uncomment the following text in config.txt:

Before:

#framebuffer_width=1280

#framebuffer_height=720

After:

framebuffer_width=1280

framebuffer_height=720

3. Save and exit the file. Then, reboot the Pi and start x11vnc by using the following command to push it into a background process: x11vnc -usepw -reopen -bg -forever &

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If you would like to start x11vnc at boot, add the following to a file called x11vnc.desktop in ~/.config/autostart:

[Desktop Entry]
Type=Application
Name=x11vnc
Exec=x11vnc -usepw -reopen -bg -forever &
Comment=Starts an x11vnc server on port kali:5900

(Note: If ~/.config/autostart does not exist, create the autostart directory by issuing the following command: mkdir ~/.config/autostart).

See how-to-execute-shell-script-on-kali-linux-startup for more information on application autostart on Kali Linux.