Hello and good evening on day two of the chaos communication Camp 2023 Translated by {Yang}{Li} (ITKST56 course assignment at JYU.FI)]
it's late in the evening this is meleeway stage in case you're wondering
and the next talk is going to be about incident report responses
so if you're curious about how to even get there to have an incident response how you could prepare for an incident response and how you could support a new organization
uh, the incident response team in doing the job and trying to fix whatever broke
let's put it that way um we have the right talk for you
this is stories from the life of an incident from incident responders Harry and Chris
please a very warm Round of Applause [Applause]
so, good evening and thank you for joining us today um we will tell you a little bit of our
life as incident responders and I'm Chris I did my computer science
studies at the University of alang and Nuremberg I do this security stuff for
over 10 years now so my CV is a little bit longer at the moment I'm a detection
engineer before that I was a long time working in dfir so digital forensic incident
response in different organizations and
yeah I'm Harryr I studied electrical and computer engineering at RWTH
University and I played a lot of CTF and did some hacking stuff at chaos computer club RWTH
during my masters I worked at x41 dsac doing pen testing patch analysis
so I also have some kind of offensive security background on for around one year now I'm working at G data Advanced
analytics doing digital forensics and incident handling
first Christian will give you a short introduction and then he will tell you how a classical ransomware attack looks
like and in the second part of the talk I will tell you how the incident
responders work and what you can do in advance to make it go as smooth as possible and support the incident
response team so as Harryr told you I will probably
we'll talk about ransomware because the customers we usually have are small and
medium-sized businesses universities and hospitals and those are regularly
unfortunately regularly hit by um um
ransomware gangs the main reason for this and that's if you heard the last
talk um why they maybe not that responsive
and are not so interested in they just lack the resources so the manpower to do
uh proper security measurements to secure their systems especially in in erm
situations where you are for example in a hospital have medical devices
um which where you cannot simply install an AV on or even patch the system
because you lose the certification as a medical device then but also in in
companies manufacturing companies on the shop floor we're talking about systems
that have run times of 25 plus years so if you look back now 2023
we're talking about XP and older systems fun fact I was in a ransomware case and
Wannacry in 2017 when I got a call from from a person from the shop floor
asking me if we have a nt4 expert, um
that can tell us if WannaCry is affecting nt4 of course you don't need
to be a expert for NT-4 this one requires of course not affecting nt4
systems so due to the time uh slot we thought
memes are the best way to to tell you those stories and we have a lot of them
so in the first uh um section I tell you a little bit of how an attack Works
um there are a lot of different possibilities how you can describe and how to structure the how an attack works
there's the miter attack framework for example there was for example a talk Yesterday by Maker Salko
um here on the stage there's the original cyber kill chain from from Lockheed Martin you have
stuff from from companies like Mandy and their targeted the tech life cycle but
that's all in my opinion two two fine-grained it's that's the reason I
just take three simple steps yeah get a foothold in the door
look move play around and cash out those three uh I will just go over
so start with uh get a foot in the door so normally we
see three ways how attackers can can get into the environment in the ransomware
cases you have vulnerabilities in uh remote uh internet facing systems you
have the remote Services itself and you have malware
starting with the with the the vulnerabilities and um I just looked uh up the last four
years and maybe somebody remembers netscaler the the so-called Citrix
vulnerability in December 2019 um it was released mid of uh 2019 uh
December 2019 the first POC publicly available POC was in beginning of
January and the patch was available in middle of January so there was a round one week to one and a half weeks between
a public proof of concept for the vulnerability and uh patch for the vulnerability and what we saw
during 2020 a lot of companies patched but the patch didn't remove the the
compromise so they were already compromised and um yeah with it with the patch they
didn't remove the compromise so what we found what we could provable
see or proof evidence for uh was nine
month uh customer was breached after nine months using this this vulnerability
and we had other customers where we could see that the netscaler was affected after two years but we couldn't
prove that this this compromise was the reason for the actual ransomware case
and of course such vulnerabilities happen not that often
yeah so 2021 gave us uh hafnium exchange
vulnerability also a similar situation the patch
appeared as an out-of-band patch from Microsoft on a Tuesday evening 10 o'clock in German time
we saw during our uh incidents or the the assessments we did that
um the first exploit exploitation attempts were seen on Wednesday in the morning at
5:00 am so around seven eight hours later um I know one guy who could patch
because he was online when the patch was released otherwise Germany was unable to patch in
time and of course we can go on with 2021 proxy shell also
exchange vulnerability proxy nutshell also exchange vulnerability
we have uh in 2022 VMware Horizon the the virtual desktop infrastructure
from VMware just to name also open source stuff Zimbra a collaboration platform
including an email server uh has had a vulnerability actually the vulnerability
was in cpio from 2015 I think which led
to a compromise using via email so you send an email
with a cpio with a specially crafted archive file and you could drop a web
shell in one of the directories yeah you have of course 40 OS which is a
40 gate VPN and firewall operating system
and if you read the news we start at the beginning again
netscaler had some issues several weeks ago according to foxIT we have 1900
still unpatched net scalers worldwide how many patched
was netscale has exists that um have not been checked for compromise we
don't know of course so that will be a nice year probably
um so what can you can you do against this kind of of attack vector patch your systems is one thing as you
see this that doesn't lead to the the um or what you need to do afterwards in
such cases you need to check your systems for possible compromise
that is important to reduce this I highly suggest put your
uh Services behind some VPN so that only people who already have
connection to the VPN um can access your services or the services
they need and that would reduce the attack surface
at least to the VPN server so but I
of course we can also think about remote services without vulnerabilities
um there can be configuration mistakes so the admin does something wrong there can
be insecure default configurations like this um I don't know if you know it but the
local admins or the administrators on the Windows system are are
automatically in the remote desktop users group you know and so
we had several cases especially in the beginning of the pandemic when everybody moved from uh to the home offices and
they needed to put people fast in the position to to access their the assist
the internal systems again they just put a RDP server on the internet and hope for the best
um additionally if you put services on the internet of course brute forcing and
credential uh stuffing are attacks that are possible so brute forcing just trying the the
username and password combinations uh credential stuffing using already leaked
passwords or credentials from leaks you find on the internet
what you can do about this kind of of attack Vector is uh just as I said use
multi-factor Authentication and reduce the attack surface as in the
point with the vulnerabilities before by moving the services behind a VPN and
then use multi-factor authentication on VPN of course
the last Vector that we see normally that the attackers can get in the
network is malware we all know this about
those funny emails you get with the attachments
um include that have either Word documents
attached either zip files with with Visual Basic scripts javascripts and
what you can get isos you see a lot these days
um or what you can also have that you can have just a link inside the email and
you download the respective file from some some shady file sharing website
um what we saw over the last year was uh USB sticks again funnily
um I'm not sure if you have heard about raspberry Robin which is a malware that
warms via USB sticks um but I haven't seen it as a vector for
ransomware yet on my own but there are people who said that it's
an initial access broker for some of the ransomware gangs
so what can you do about this if you think the
you can of course ban simply some file extensions in your mail server or you
change the file Association types in your operating system meaning that you
don't open the JavaScript and Visual Basic script files using for example the
windows scripting host but open it with notepad and that will
of course some people will be
uh some people will think about what this this is then and ask the IT guys
but it's better than running the the script itself
one thing I I I don't like to to say it but keep your AV updated
um uh this is one thing keep it updated and read the logs
we see a lot of incidents where we see that the already
days or weeks before we you can could have seen that there's something going
on in your network yeah and if you see malware in your AV logs
then react to it just check it you don't know how long this AV this malware has
been on your system the thing is that
just because you're AV detected it now it might have been get received an
update for its signatures and the malware was active for days or weeks
before so when they are inside
then they usually look move and play around a little bit
so when they look around what they do
is they they enumerate AD they do Ports scan the you they search for
vulnerabilities they check uh what they how they can escalate
their privileges they try to find credentials
um Kerber roasting we heard in the talk before for example is this one thing
um they try to identify accounts you around
have running on your systems they can use they can get the credentials from and you reuse
and for that reason one of the most important things I think is that you
have a principle of least privileges in your environment so only what a account needs
you should be able to do you should use dedicated service
accounts for your services of course and just for your information