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Re: [LUG] viruses and protecting against them

 

On 14/11/2018 08:14, Pentiddy wrote:
> Hi all,
> still seem to be having a few issues, and wondered if you might be able 
> to comment on the following entries in the syslog...
> 
> whoopsie[1317]: [06:38:06] Cannot reach: https://daisy.ubuntu.com
> nm-dispatcher: req:2 'down' [enp58s0f1]: new request (2 scripts)
> nm-dispatcher: req:2 'down' [enp58s0f1]: start running ordered scripts...
> 
>   kernel: [13599.181267] wlp59s0: deauthenticating from 
> 00:17:3f:17:ea:21 by local choice (Reason: 3=DEAUTH_LEAVING)
> 
> and this from the session I just started...
> 
> Nov 14 07:37:37 pentiddy-UltraNoteIV-15 dbus-daemon[1459]: [session 
> uid=1000 pid=1459] Activating service 
> name='org.freedesktop.thumbnails.Thumbnailer1' requested by ':1.18' 
> (uid=1000 pid=1569 comm="Thunar --daemon " label="unconfined")
> Nov 14 07:37:38 pentiddy-UltraNoteIV-15 
> org.freedesktop.thumbnails.Thumbnailer1[1459]: Registered thumbailer 
> /usr/bin/gdk-pixbuf-thumbnailer -s %s %u %o
> Nov 14 07:37:38 pentiddy-UltraNoteIV-15 
> org.freedesktop.thumbnails.Thumbnailer1[1459]: Registered thumbailer 
> /usr/bin/gdk-pixbuf-thumbnailer -s %s %u %o
> Nov 14 07:37:38 pentiddy-UltraNoteIV-15 
> org.freedesktop.thumbnails.Thumbnailer1[1459]: Registered thumbailer 
> atril-thumbnailer -s %s %u %o
> Nov 14 07:37:38 pentiddy-UltraNoteIV-15 
> org.freedesktop.thumbnails.Thumbnailer1[1459]: Registered thumbailer 
> gnome-thumbnail-font --size %s %u %o
> Nov 14 07:37:38 pentiddy-UltraNoteIV-15 dbus-daemon[1459]: [session 
> uid=1000 pid=1459] Successfully activated service 
> 'org.freedesktop.thumbnails.Thumbnailer1'
> Nov 14 07:37:46 pentiddy-UltraNoteIV-15 CRON[881]: (root) CMD ([ -x 
> /etc/init.d/anacron ] && if [ ! -d /run/systemd/system ]; then 
> /usr/sbin/invoke-rc.d anacron start >/dev/null; fi)
> Nov 14 07:37:50 pentiddy-UltraNoteIV-15 gvfsd-metadata[4274]: 
> g_udev_device_has_property: assertion 'G_UDEV_IS_DEVICE (device)' failed
> 
> Some of these entries are possible problems maybe?
> Don't like the look of the root command above- I have not set any CRON 
> jobs...
> 
> If these are suspicious and therefore my system is still compromised 
> after a re-install, the infection must be somewhere in the files I 
> backed up.
> I'm assuming most would now say head to windows for visrus scanning as 
> Mr Meowski has suggested...
> 
> Thanks all,


That's all just legit system chatter - anacron will be in charge of 
running standard cron stuff (check with 'systemctl status anacron' and 
read /etc/anacrontab) and is installed by default. Most of the rest is 
the thumbnailer deamon being registered for use by Thunar which wants to 
generate some pretty icons for you. There's a normal deauth from your 
wifi and the Ubuntu error reporting daemon 'whoopsie' - which you should 
probably apt purge - was briefly having issues talking to the homebase 
(daisy.ubuntu.com). By the looks of it you were just turning the system 
on at before 7am and whoopsie was trying to report back before 
networkmanager had finished doing it's thing and bringing the wifi up 
properly.

So, all completely normal - at least from that excerpt. Problem is there 
are a few tens of thousands more lines like that in your logs and more 
being added every minute. To someone who hasn't wasted as much of their 
life reading logfiles as me they're pretty incomprehensible and 
absolutely full of stuff that _looks_ really suspect.

You're _probably_ in the clear - especially as you did a clean install 
anyway I believe, it's just the files and data you carried over that are 
still worrying you?

May I cautiously re-suggest that you are making things hard for yourself 
here. If you're that worried about this, scan all the files, with 
Windows. You can setup a VM with a free (as in beer, obviously, not 
freedom) shiny new Win10 instance in a few minutes on a fast machine and 
add a bunch of different scanners to it for peace of mind. Expose your 
suspicious files to it via a read-only share from Linux and let it loose 
for a while. This is an advanced sysadmin procedure we call "using the 
right tool for the job and not prevaricating endlessly about what might 
happen instead of just getting on and fixing it so we can carry on with 
our lives in peace".

To be clear, as MJE hinted in his brave hat-endangering reply Linux 
virii aren't really a thing - malware certainly exists for Linux and 
Linux as a platform is certainly a tempting target for hackers but Linux 
_so far_ hasn't had any of the catastrophic Windows-type virus outbreaks 
that are so common in Microsoft environments. After a clean install the 
chance of your actual Ubuntu OS being compromised in itself is pretty 
insignificant but like a carrier who is immune to the virus they 
incubate it is definitely possible for your Linux box to be housing 
compromised files that will wreak havoc on any unsuspecting Windows user 
who opens them (or you send them to). AV for Linux isn't really AV for 
Linux at all - generally speaking we run it only as a courtesy to our 
Windows using comrades to stop accidentally passing on crap that we're 
immune to but they are not. This is what Clam AV is largely used for for 
example - it's not installed to protect the Linux host it runs on, it's 
really only there normally as a milter to run mail through in passing to 
help out the (relatively speaking) weak and sickly Windows boxes who 
might end up it with it in their Outlook inboxes... God help them.

So just tool up with a Windows VM and get the proper scan over and done 
with and then you can put the whole thing behind you as a learning 
experience. It's either that or "take off and nuke it from orbit" which 
is the surefire way of killing off all malware but I'm presuming you'd 
like your data to actually survive so sadly you're going to have to make 
do with just scanning it properly.

Cheers
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