Is my Vino server being attacked?

Question

I installed vino on LUbuntu 18.04, and configured and started my vino server according to https://askubuntu.com/a/530196/1471 without understanding what the commands mean:

$ export DISPLAY=:0
$ gsettings set org.gnome.Vino enabled true # although fails, it doesn't matter
No such key “enabled”
$ gsettings set org.gnome.Vino prompt-enabled false
$ gsettings set org.gnome.Vino require-encryption false    
$ /usr/lib/vino/vino-server

From ifconfig and the output message of starting the server, I found the server's internal ip is 192.168.1.3 and port is 5900. I connected to the server from RealVNC's VNC viewer on my Android phone within the same WIFI network, and the authentication I was only asked to provide was the password to login to my Ubuntu. Our wifi network was set up by a previous tenant, and ISP is Verizon FIOS, and there is no special set up about it.

In the monitoring output message of the server (see below), I can only guess that android-c28b29b650f6548c.home is the client on my android phone, but I don't know who the clients 46.101.184.149, zg-0817a-64.stretchoid.com, 196.52.43.118, and scan-06.shadowserver.org belong to, except finding the following:

Questions:

Is it correct that my vino server is being accessed from some dangerous clients other than the client on my android phone?
I haven't tried to do any thing explicitly to make my vino server available to the Internet (or I am not aware that I did it), so how could these clients find and connect my server from the Internet?
How can I check on my Ubuntu to see if they have done some damage?
What can I do to securely use my VNC server, if necessary?

Thanks.

$ /usr/lib/vino/vino-server

(vino-server:32529): dbind-WARNING **: 19:44:12.185: Error retrieving accessibility bus address: org.freedesktop.DBus.Error.ServiceUnknown: The name org.a11y.Bus was not provided by any .service files
19/08/2018 07:44:12 PM Autoprobing TCP port in (all) network interface
19/08/2018 07:44:12 PM Listening IPv6://[::]:5900
19/08/2018 07:44:12 PM Listening IPv4://0.0.0.0:5900
19/08/2018 07:44:12 PM Autoprobing selected port 5900
19/08/2018 07:44:12 PM Advertising security type: 'TLS' (18)
19/08/2018 07:44:12 PM Re-binding socket to listen for VNC connections on TCP port 5900 in (all) interface
19/08/2018 07:44:12 PM Listening IPv6://[::]:5900
19/08/2018 07:44:12 PM Listening IPv4://0.0.0.0:5900
19/08/2018 07:44:12 PM Clearing securityTypes
19/08/2018 07:44:12 PM Advertising security type: 'TLS' (18)
19/08/2018 07:44:12 PM Clearing securityTypes
19/08/2018 07:44:12 PM Advertising security type: 'TLS' (18)
19/08/2018 07:44:12 PM Advertising authentication type: 'No Authentication' (1)
19/08/2018 07:44:12 PM Re-binding socket to listen for VNC connections on TCP port 5900 in (all) interface
19/08/2018 07:44:12 PM Listening IPv6://[::]:5900
19/08/2018 07:44:12 PM Listening IPv4://0.0.0.0:5900
19/08/2018 07:44:12 PM Clearing securityTypes
19/08/2018 07:44:12 PM Clearing authTypes
19/08/2018 07:44:12 PM Advertising security type: 'TLS' (18)
19/08/2018 07:44:12 PM Advertising authentication type: 'VNC Authentication' (2)
19/08/2018 07:44:12 PM Clearing securityTypes
19/08/2018 07:44:12 PM Clearing authTypes
19/08/2018 07:44:12 PM Advertising security type: 'TLS' (18)
19/08/2018 07:44:12 PM Advertising authentication type: 'VNC Authentication' (2)
19/08/2018 07:44:12 PM Advertising security type: 'VNC Authentication' (2)
19/08/2018 07:44:17 PM [IPv4] Got connection from client android-c28b29b650f6548c.home
19/08/2018 07:44:17 PM   other clients:
19/08/2018 07:44:17 PM Client Protocol Version 3.7
19/08/2018 07:44:17 PM Advertising security type 18
19/08/2018 07:44:17 PM Advertising security type 2
19/08/2018 07:44:17 PM Client returned security type 2

** (vino-server:32529): WARNING **: 19:44:28.888: VNC authentication failure from 'android-c28b29b650f6548c.home'

19/08/2018 07:44:28 PM rfbAuthPasswordChecked: password check failed
19/08/2018 07:44:28 PM Client android-c28b29b650f6548c.home gone
19/08/2018 07:44:28 PM Statistics:
19/08/2018 07:44:28 PM   framebuffer updates 0, rectangles 0, bytes 0
19/08/2018 07:44:30 PM [IPv4] Got connection from client android-c28b29b650f6548c.home
19/08/2018 07:44:30 PM   other clients:
19/08/2018 07:44:30 PM Client Protocol Version 3.7
19/08/2018 07:44:30 PM Advertising security type 18
19/08/2018 07:44:30 PM Advertising security type 2
19/08/2018 07:44:30 PM Client returned security type 2

** (vino-server:32529): WARNING **: 19:44:40.531: Deferring authentication of 'android-c28b29b650f6548c.home' for 5 seconds

19/08/2018 07:44:45 PM rfbProcessClientNormalMessage: ignoring unknown encoding type 22
19/08/2018 07:44:45 PM rfbProcessClientNormalMessage: ignoring unknown encoding type 21
19/08/2018 07:44:45 PM rfbProcessClientNormalMessage: ignoring unknown encoding type 15
19/08/2018 07:44:45 PM rfbProcessClientNormalMessage: ignoring unknown encoding type -314
19/08/2018 07:44:45 PM Enabling NewFBSize protocol extension for client android-c28b29b650f6548c.home
19/08/2018 07:44:45 PM Pixel format for client android-c28b29b650f6548c.home:
19/08/2018 07:44:45 PM   8 bpp, depth 6
19/08/2018 07:44:45 PM   true colour: max r 3 g 3 b 3, shift r 4 g 2 b 0
19/08/2018 07:44:45 PM Pixel format for client android-c28b29b650f6548c.home:
19/08/2018 07:44:45 PM   32 bpp, depth 24, little endian
19/08/2018 07:44:45 PM   true colour: max r 255 g 255 b 255, shift r 16 g 8 b 0
19/08/2018 07:44:45 PM no translation needed

Gtk-Message: 20:43:41.511: GtkDialog mapped without a transient parent. This is discouraged.
Gtk-Message: 20:43:44.339: GtkDialog mapped without a transient parent. This is discouraged.
Gtk-Message: 20:43:52.072: GtkDialog mapped without a transient parent. This is discouraged.
19/08/2018 10:39:57 PM [IPv4] Got connection from client 46.101.184.149
19/08/2018 10:39:57 PM   other clients:
19/08/2018 10:39:57 PM      android-c28b29b650f6548c.home
19/08/2018 10:39:57 PM Client Protocol Version 3.3

** (vino-server:32529): WARNING **: 22:39:57.238: VNC authentication failure from '46.101.184.149'

19/08/2018 10:39:57 PM rfbAuthPasswordChecked: password check failed
19/08/2018 10:39:57 PM Client 46.101.184.149 gone
19/08/2018 10:39:57 PM Statistics:
19/08/2018 10:39:57 PM   framebuffer updates 0, rectangles 0, bytes 0
19/08/2018 10:43:41 PM [IPv4] Got connection from client 46.101.184.149
19/08/2018 10:43:41 PM   other clients:
19/08/2018 10:43:41 PM      android-c28b29b650f6548c.home
19/08/2018 10:43:41 PM Client Protocol Version 3.3

** (vino-server:32529): WARNING **: 22:43:41.812: Deferring authentication of '46.101.184.149' for 5 seconds


** (vino-server:32529): WARNING **: 22:43:47.449: VNC authentication failure from '46.101.184.149'

19/08/2018 10:43:47 PM rfbAuthPasswordChecked: password check failed
19/08/2018 10:47:27 PM [IPv4] Got connection from client 46.101.184.149
19/08/2018 10:47:27 PM   other clients:
19/08/2018 10:47:27 PM      46.101.184.149
19/08/2018 10:47:27 PM      android-c28b29b650f6548c.home
19/08/2018 10:47:27 PM Client Protocol Version 3.3

** (vino-server:32529): WARNING **: 22:47:27.692: Deferring authentication of '46.101.184.149' for 5 seconds


** (vino-server:32529): WARNING **: 22:47:32.452: VNC authentication failure from '46.101.184.149'

19/08/2018 10:47:32 PM rfbAuthPasswordChecked: password check failed
19/08/2018 10:51:12 PM [IPv4] Got connection from client 46.101.184.149
19/08/2018 10:51:12 PM   other clients:
19/08/2018 10:51:12 PM      46.101.184.149
19/08/2018 10:51:12 PM      46.101.184.149
19/08/2018 10:51:12 PM      android-c28b29b650f6548c.home
19/08/2018 10:51:12 PM Client Protocol Version 3.3

** (vino-server:32529): WARNING **: 22:51:12.833: Deferring authentication of '46.101.184.149' for 5 seconds


** (vino-server:32529): WARNING **: 22:51:18.448: VNC authentication failure from '46.101.184.149'

19/08/2018 10:51:18 PM rfbAuthPasswordChecked: password check failed
19/08/2018 10:54:58 PM [IPv4] Got connection from client 46.101.184.149
19/08/2018 10:54:58 PM   other clients:
19/08/2018 10:54:58 PM      46.101.184.149
19/08/2018 10:54:58 PM      46.101.184.149
19/08/2018 10:54:58 PM      46.101.184.149
19/08/2018 10:54:58 PM      android-c28b29b650f6548c.home
19/08/2018 10:54:58 PM Client Protocol Version 3.3

** (vino-server:32529): WARNING **: 22:54:58.339: Deferring authentication of '46.101.184.149' for 5 seconds


** (vino-server:32529): WARNING **: 22:55:03.449: VNC authentication failure from '46.101.184.149'

19/08/2018 10:55:03 PM rfbAuthPasswordChecked: password check failed
19/08/2018 10:58:43 PM [IPv4] Got connection from client 46.101.184.149
19/08/2018 10:58:43 PM   other clients:
19/08/2018 10:58:43 PM      46.101.184.149
19/08/2018 10:58:43 PM      46.101.184.149
19/08/2018 10:58:43 PM      46.101.184.149
19/08/2018 10:58:43 PM      46.101.184.149
19/08/2018 10:58:43 PM      android-c28b29b650f6548c.home
19/08/2018 10:58:43 PM Client Protocol Version 3.3

** (vino-server:32529): WARNING **: 22:58:43.756: Deferring authentication of '46.101.184.149' for 5 seconds


** (vino-server:32529): WARNING **: 22:58:49.448: VNC authentication failure from '46.101.184.149'

19/08/2018 10:58:49 PM rfbAuthPasswordChecked: password check failed

19/08/2018 11:02:28 PM [IPv4] Got connection from client 46.101.184.149
19/08/2018 11:02:28 PM   other clients:
19/08/2018 11:02:28 PM      46.101.184.149
19/08/2018 11:02:28 PM      46.101.184.149
19/08/2018 11:02:28 PM      46.101.184.149
19/08/2018 11:02:28 PM      46.101.184.149
19/08/2018 11:02:28 PM      46.101.184.149
19/08/2018 11:02:28 PM      android-c28b29b650f6548c.home
19/08/2018 11:02:28 PM Client Protocol Version 3.3

** (vino-server:32529): WARNING **: 23:02:28.345: Deferring authentication of '46.101.184.149' for 5 seconds


** (vino-server:32529): WARNING **: 23:02:33.449: VNC authentication failure from '46.101.184.149'

19/08/2018 11:02:33 PM rfbAuthPasswordChecked: password check failed
19/08/2018 11:30:51 PM [IPv4] Got connection from client zg-0817a-64.stretchoid.com
19/08/2018 11:30:51 PM   other clients:
19/08/2018 11:30:51 PM      46.101.184.149
19/08/2018 11:30:51 PM      46.101.184.149
19/08/2018 11:30:51 PM      46.101.184.149
19/08/2018 11:30:51 PM      46.101.184.149
19/08/2018 11:30:51 PM      46.101.184.149
19/08/2018 11:30:51 PM      46.101.184.149
19/08/2018 11:30:51 PM      android-c28b29b650f6548c.home
19/08/2018 11:31:01 PM rfbProcessClientProtocolVersion: client gone
19/08/2018 11:31:01 PM Client zg-0817a-64.stretchoid.com gone
19/08/2018 11:31:01 PM Statistics:
19/08/2018 11:31:01 PM   framebuffer updates 0, rectangles 0, bytes 0
sendto: Network is unreachable
sendto: Network is unreachable
20/08/2018 10:37:54 AM rfbProcessClientNormalMessage: read: Connection reset by peer
20/08/2018 10:37:54 AM Client android-c28b29b650f6548c.home gone
20/08/2018 10:37:54 AM Statistics:
20/08/2018 10:37:54 AM   key events received 32, pointer events 3932
20/08/2018 10:37:54 AM   framebuffer updates 7016, rectangles 13714, bytes 270216867
20/08/2018 10:37:54 AM     ZRLE rectangles 13714, bytes 270216867
20/08/2018 10:37:54 AM   raw bytes equivalent 538553044, compression ratio 1.993040
20/08/2018 02:15:10 PM [IPv4] Got connection from client 196.52.43.118
20/08/2018 02:15:10 PM   other clients:
20/08/2018 02:15:10 PM      46.101.184.149
20/08/2018 02:15:10 PM      46.101.184.149
20/08/2018 02:15:10 PM      46.101.184.149
20/08/2018 02:15:10 PM      46.101.184.149
20/08/2018 02:15:10 PM      46.101.184.149
20/08/2018 02:15:10 PM      46.101.184.149
20/08/2018 02:15:10 PM Client Protocol Version 3.7
20/08/2018 02:15:10 PM Advertising security type 18
20/08/2018 02:15:10 PM Advertising security type 2
20/08/2018 02:15:10 PM Client returned security type 1
20/08/2018 02:15:10 PM rfbAuthProcessSecurityTypeMessage: client returned unadvertised security type 1
20/08/2018 02:15:10 PM Client 196.52.43.118 gone
20/08/2018 02:15:10 PM Statistics:
20/08/2018 02:15:10 PM   framebuffer updates 0, rectangles 0, bytes 0
20/08/2018 02:31:26 PM [IPv4] Got connection from client scan-06.shadowserver.org
20/08/2018 02:31:26 PM   other clients:
20/08/2018 02:31:26 PM      46.101.184.149
20/08/2018 02:31:26 PM      46.101.184.149
20/08/2018 02:31:26 PM      46.101.184.149
20/08/2018 02:31:26 PM      46.101.184.149
20/08/2018 02:31:26 PM      46.101.184.149
20/08/2018 02:31:26 PM      46.101.184.149
20/08/2018 02:31:28 PM rfbProcessClientProtocolVersion: client gone
20/08/2018 02:31:28 PM Client scan-06.shadowserver.org gone
20/08/2018 02:31:28 PM Statistics:
20/08/2018 02:31:28 PM   framebuffer updates 0, rectangles 0, bytes 0

In order to use the Android client, you have to turn off the VNC encryption. This makes it less secure. I am frustrated that no Android client supports this encryption, but so it goes. — Organic Marble, Aug 20 '18 at 23:46
You shouldn't make port 5900 available to the internet, but instead connect over ssh as @user535733 says. However, it appears that random people from the internet are able to access your LAN, if port 5900 is not open to the Internet. — Organic Marble, Aug 20 '18 at 23:50
@OrganicMarble Thanks. How can I make sure port 5900 in my Lubuntu is not open to the internet? How can I check if there is some abnormal network activity on my Lubuntu? — Tim, Aug 20 '18 at 23:53
The visibility of ports is most likely controlled by your router settings. That will be highly dependent on manufacturer and model so I can't give directions. — Organic Marble, Aug 20 '18 at 23:55

user535733 · Accepted Answer · 2018-08-21T00:00:39.257

2

Use SSH to provide a secure connection for VNC. As a bonus, this means connections can use your existing, secure SSH keys instead of hard-to-remember or insecure passwords.

How it works, and how to set it up, is explained in detail at https://help.ubuntu.com/community/VNC

Since it's possible that your VNC server has already been compromised, practice safe computing and nuke-and-reinstall that instance of Ubuntu.

edited Aug 21 '18 at 00:00

answered Aug 20 '18 at 23:28

user535733

62,253

Thanks. Is it sufficient to reinstall vino? Reinstall Lubuntu is too much. – Tim Aug 20 '18 at 23:36
On my Android, how can I use ssh port forwarding? – Tim Aug 20 '18 at 23:39
Do you know how those illegal clients can find and connect to my vino server in my local wifi network? – Tim Aug 20 '18 at 23:40
How can I check if any damage on my Lubuntu? Just don't want to reinstall it. I haven't found any thing weird, and has stopped running vino server. – Tim Aug 20 '18 at 23:42
Without professional help it's safest to nuke your install and rebuild it if you are sure a breach occurred. – Organic Marble Aug 20 '18 at 23:43
@Tim - if an intermediate user could spot evidence of an intruder, then it would be poor workmanship indeed. Hence the recommendation to take the safe course. – user535733 Aug 21 '18 at 00:03
Thanks. Could you help with my second comment? – Tim Aug 21 '18 at 00:19

Is my Vino server being attacked?

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