My name is Jim Nitterauer, I'm a senior security specialist with Appriver. Appriver was just
recently purchased by Zix Corporation. I don't know the specifics, as the buyout happened a few weeks ago. This talk is entitled
Decrypting the Mess that is SSL / TLS Negotiation - Preparing for the 2020 Apocalypse.
Now Disclaimer, this isn't gonna be very technical. It's gonna' be a bit of an overview of
ssl/tls and what you need to do to make sure things don't go wrong. When this happens. i had to give a fancy title for the talk.
all right so, disclaimer. The information you're going to hear today is just for your own security.
And privacy policies should be used or under the purposes that are not my own
research for this information about gathering from other sources. The information
people's evidence cavity public private sources and I give it credit where
that's due. And the views expressed in talk are mine and not of that of my employers. I've
spoken a bunch of different places among standard besides Las Vegas. Some I'm at Def
Con, Circle City Com retreat on his head would get involved with these
conferences so I have a little bit of experience in the stuff.
I saw an invite to come to CypherCon from a friend of mine Dave Schwartzberg and I was trying to
think of something to talk about because, normally I talk about DNS so this is for
Will. This is the only mention of DNS in the whole talk. I saw this come across my
desk in my news where I was reading where about Chrome and Firefox, I.E. which is
now gone. To buy he looks down it will be chromium in the next windows major
update and Safari are gonna disable TLS 1.0 until TLS 1.1 support in 2020. This
specifically is gonna happen by the end of March 2020. It's already happened
in some versions, but this seems like a pretty benign headlock right? Well think
about the implications of this prompt and an end user
perspective and from a server perspective, and that's kind of what
we're going to look at. So if you are either are IT desktop management, your
internal management, you know how to prepare for this or if you're running servers,
websites, API's, mail servers, you can start to look at your tls/ssl setup and
make sure that you're going to be compliant so that people don't call you
complaining. Hey I can't get to a website? Or hey, why is your website not working in my browser? Why doesn't yyour email
server not work? Is the kind of things that can bite you in the butt if you don't
pay attention to them. So we want to go over some things about how to avoid
those things from happening. So, today we're gonna have a quick
overview. We're gonna look at the different versions of SSL and TLS. Look
at the differences in the history we're going to talk about the SSL negotiation
process but going forward the terminology should be TLS as SSL based
on exist anymore it's completely shouldn't be used anywhere we're going
to look at the differences between TLS 1.2 and TLS 1.3 which was just ratified
last year why that's 270 lost versus corporate
matters we're going to look at some of the vulnerabilities and the types of
attacks that can be carried out against TLS and SSL correctly I don't know much
details when we give you a quick overview of some up woman to the basic
mechanisms of how they work we're gonna look at some strategies for monitoring
TLS negotiation at the edge of your network this is important you have to
know what your clients are trying to connect to how they're trying to connect
and how the conversation happens we're gonna look at some example data that
gonna show you data that we use in production it's nothing proprietary I'll
just show you how we can prepare for this in our environment one of our
services and we're going to look at some ways when you take that contravene use
it to implement some protection on our network to keep some of these attacks
from happening and I'll give you some resources at the end to help you on your
task or getting tell us SSL ready to go what is tls/ssl basically
the overall goal of TLS is to protect privacy and integrity of data
flowing over connection between two endpoints typically the first thing that
comes to mind is what web browser right but browse HTTP that's a TLS SSL
connection but it also works IMAP SMTP works and every API every
application on your phone should be using SSL TLS
between the two endpoints so basically it's a way to achieve that the client
knows that the endpoint server is validated it's who they think they are
and of the data in between is encrypted and some of the great progress in that
message so how does that happen it's basically to do that process the
first step is using public key for asymmetric cryptography so you have that
public key that's managed by a by a trusted source of third-party trusted
source Marisa let's encrypt is pretty common now right so that's pretty
significant you validate who you are as a server as a recipient of the can
actually by providing your public key out to the world my client this looks at
that public key send the request to you that you decrypt that encrypted
connection with to a private key because it matches and how we know that the two
are the validate and then once that connection although more detail how this
happens once that connection is then established the authentication we switch
to a much faster symmetric cryptography think of like IPSec
tunnel it depends on that uses symmetric cryptography where a key is agreed upon
at the time using a cipher suite and the mechanism or the
their version of tell us that they're using and that key is used for every
conversation they both know the key they both use the same team so there's no
need for continuous bass a symmetric cryptography so some of the things we
have to look out for in SSL TLS is that it's validated through a public key
cryptography now you can do this internally with your own self sign keys
but that through the browser error must generate certification theatres with
that in your browser so there's ways you can get around that internally but
typically we're talking about public connections to public facing servers not
internal connections the PKI always has a certificate revocation path that a
doesn't you won't get an A+ on your rating for your servers perfect forward
secrecy anybody heard of that term before all right so what this what this
means is that every time there is a agreed-upon symmetric key used to
encrypt the second part of the connection that that key has a nonce or
some sort of padding that's read upon by both sides of it one time to generate
that keep so that's important because what if somebody compromises a server
each private key if they could sniffing your traffic over time even if it's
encrypted if they have your private key they can decrypt all of that traffic
right because then they know what the agreed-upon asymmetric key moves but if
you change how it's mentioned he's generated for every connection that
cannot decrypt anything but that one can actually when they get the private key
okay so it's a way to prevent that fact and it should always be in play it's not
always in play and it's not supported in the older versions of SSL
the other thing we have to look at are what client-server applications are we
talking about the most common one obviously is HTTP I'm atmospher
everybody much as on your property of googlemail
that's my mattress done through secure I think that exchanges come through HTTP
should be using it smtps has anybody ever been at DEFCON sea wall sheep wall
of shame where people are using insecure pop and ice MTP is 70 ml back and forth
their passwords when you use remain show up in clear text on the wire right to
even Wireshark them screen see what they are that's why you want to be using the
encrypted version space protocols some brief history SSL was introduced by
Netscape in 1994 it was never released in version 1 because we're serious owner
abilities in version 2 was released in 1995 it's a hip month time on here
actually 94 right 25 years ago so this is over - in 1995 was the first usable
version with SSL welcome use a whole lot at the time version 3 plays one year
later and we're still seeing SSL 3.0 I was in a while after three years fix
several design security flaws tell us one point I was released in 1999 so not
for three years later we can upgrade to SSL version 3 but they introduced the
vulnerability into that protocol in that prototype that vulnerability is the SSL
fallback mechanism really nobody thought anything about it but now it's one of
the biggest ways that people can do DDoS attacks against services that still
support downgrading of TLS connections I'll explain more about this in a few
minutes last the next version of TLS came out in April 2006 so looking in
seven years later it protected against cipher block chaining attacks in 2008 so
two years later the Oscar one two came out all those 2008 put
vrc's a marination when i go back later and look at those and it had a site
birth sweet specific pseudo-random function this is where it came into the
ability to create the perfect forward secrecy so that it could not decrypt
previous conversations if you got the private key and also removed a couple of
the less secure cipher suites SSL version 2.0 was deprecated in 2011 and
has been recommended for complete abandonment it has been removed from
pretty much every browser that's out there if you try to connect by cell 2.0
it just not network services they're using it
tell us version 1.3 was released in August last year with the RFC it's a
10-year revision process from TLS 1.2 it removes several of the less secure
Cypress or sha-1 md5 rc4 that is a triple desert no longer be usable in TLS
1.3 and it also does something called the serve name identifier encryption so
if you have any of you have looked at encrypting and decrypting SSL
connections on your network where you can actually look at where they're gone
so a lot of the things that you see are using tell us to point at one point or
above is a server named indicator which is basically an unencrypted packet that
tells you the domain image of going to and coming from within the encrypted DLS
within that cryptid strength well tell us versus 1.3 is going to encrypt that
so any security that you're doing on any time to less connections with 1.3 won't
be able to do won't be able to man in the middle attacks very easily with it
with this conversion so it's going to change how security's done for TLS
connections there's a kind of the resources here if you want to look at a
long history of TLS and SSL and all the vulnerabilities and how it's done over
timeline that place need is pretty good place to start so let's
look at basically how to tell us SSL connection process work and this is
going to apply to both SSL TLS 1.1 1.2 1.3 / it's the same plan so this is the
OSI model basically the basic Network layer so all the connectivity happens at
layer 4 below for the TCP connection but within that there's the application
layer which is MB HTTP SMTP my map doesn't matter but everything else is
the same so the first stage of this is SSL handshake this is the part of the
lives on symmetric key cryptography the second part is the SSL cyber exchange
and the data transfer and that's all done through asymmetric cryptography so
there's just a visual on how all this takes place so part 1 what happened
basically to every SSL TLS connection determine the cipher suite to be used
that the terms of protocol version to be used and then again it requires
asymmetric cryptography keep in mind that the public key is validated by a
certificate and the private key is known only to the server typically this is
only one way of authentication so if your growlithe making a connection to
somewhere the secure your browser disability publicly
validates the server now there are times where certain types of connections has
anyone ever been to one where they require that you have a client
certificate so this is the same as if you go to like DEFCON earlier conference
you'll download the certificate to get on the Wi-Fi network
you're basically validating that your client or your ballot to the server
right it's not the other way around that happens sometimes in tls/ssl connections
particularly when you're doing and then transfers funds maybe two backs
transferring data back and forth they'll require the tokens
can actually do a authentications they call that two way authentication but
most of all the way authentication didn't have a promise for certificated
what route keep in mind that tell us version 1.2 unless requires three round
trips to the server a four for doing the client authentication as well just gives
you a little overview of how that works first thing happens is you login type in
HTTPS whether you're going to and goes hey I'm lying out there on my sensing
data to you but I want to do it securely and here's the site which needs to
support here's the protocols I support server goes great sentiments and back
here's the server here's the protocol less important recycle sheets I support
then they both agreed on hopefully the strongest cipher sweet and strong this
level of support and then what will happen is they agree that they can talk
to each other because the certificate matches that the gross now we go to the
asymmetric part and that what's called a pre master key I'm sorry the symmetric
part they pre master keys generated using a public key and then after that
the keys are exchanged they both know same key that their dreams were
exchanging the data of the day of transfer layer so that's basically a
handshake process the data transfer happens at the very end of that the last
step after agreeing on a session key word will appear this the master session
use different terminology so it gets a little confusing Ultimate Edition
between the endpoints occurs via the use of the exact negotiated key for
encrypting and decrypting every fact that goes across that connection so if
you're in an HTTP environment you got equalized and exit stays open for a long
period of time typically an email connection we've got pipelining of
messages now server to the others would not
renegotiating that connection for every message that's getting sent and that
that information stays current until the connections drop once that connections
drop the renegotiated connection have to go through the whole process again to
restart and gather the certificate and agree on master session key this is done
to protect so that if somebody gets the property they cannot be triggered every
session which immediately sent across to the server client this process is always
the most of seeing web traffic but again it applies to every type of encrypted
traffic it's the same process just different ports Justin refer to call
some underlying in the application all right so tell us one point three is a
little bit different the same basic information has to be a channel to
establish that connection but the process for exchanging the data very
first thing you know we have to remember is sort of the identifier the server
name identifier would be encrypted within the package so if you're really
firewall IDs in the middle trying to decrypt on the fly or trying to
determine load balancer they're not going to be able to see what the
information is that server name identifier the only thing you can see
that is the server and the point once it's decrypted up machine has private
keys the process that does this results in only one single round trip between
the server and client were to remember SSL all the SSL bursts of the TLS 1.2
below required at least two if not three round trips to the server to make that
connection before the transfer data so TLS 1.3 also has something built-in
called zero round-trip time resumption this is the way that the client can
reuse that agreed-upon key with the server server scores of sequels with
previous sessions that can reuse it for that client for something given
period of time and that's typically configurable on whatever platform you're
doing unless you think that's stupid right somebody could then steal or look
at that key somehow and use it to decrypt or worse they encrypt traffic
incentive that's you right there they are
I said sure other ways around that on this you see tell us one point three
there are are some there are some features that are built in and I'm not
fully familiar with how it works exactly but when I didn't look at the fallback
mechanisms it is very secure it's not that you can't break it
the lack of full forward secrecy is not something that it allows you to do until
us has the mechanisms built in to deal with both systems the diagram comes from
CloudFlare but it's a diagram of how the two different handshake mechanisms work
so you can see that this doesn't show along screen unfortunately but if you
look at the left side your left side that still has one went to unless
there's three round-trips welcome to reroute there's the server if that's
work and tell us one point three is only two round-trips and the data is
encrypted at that point so the speed of the connection is much faster there's
much better one thing that you do have to realize is
tell us one more 3 requires HTTP to be an able or every web server you're using
if you're using web services not every web server that comes out as maintenance
or HTTP 2 if you have to do something for work to make that happen so that's
something to keep in mind the triangle 1.3 assign haven't windows yet
Microsoft uses s channel has their core libraries or dash panel does not have
three bullet ending at this point in time they probably will not put it into
with this 2008 of an angel sort so if you're using Windows 2008 you're screwed
and you're gonna have to afraid of this 2016 but I would say if you're gonna do
that after the 2019 it's far better and then they will support it for that but
it's not the introduction yet so here's an overview of the things have changed
in TLS 100 some of the features that have been removed include the static var
say handshake bets on cyber cipher block chaining Mac then encryption has been
removed okay this has been shown to be a smooth ball so they remove the ability
to set this as a way to do the encryption some math and heap impact on
this encrypted inside of the package of the sense that you can't see with sha-1
nd5 marks before turtle desert as have been removed compression has been
removed that's not needed because it's kind of all the time around trip and
renegotiation is not possible so once the connection is good attacks
it's good if it has to renegotiate remember it remembers the secrets and
doesn't different the features of bananas to full handshake signature so
that's that first trip everything that first trip takes all of the information
that needs to be able to establish the protocol and the Cypress suite was being
used it's also added something or elliptic curve anytime you see easily
when the Cypress needs that central if that curve cryptography elliptic curve
cryptography is something that gives you plan gives you a higher pitch count with
encryption level with less this process by the processor that makes no sense
so if you can get something like 2048-bit encryption with maybe 860 bit
he doesn't let the curve there tog Rafi doesn't seem like it's a big deal but if
you're doing a hundred of thousands billions of transactions makes a big
deal for a processor and there's several curve variations that have been added to
TLS 1.3 so why is this important why do we care we want our stuff to work we
just want to work right so cron removed SSL version 3.0 in 2015 it's gone
energies you can use in Iran can't force it to do anything this effectively
eliminates all SSL burdens that are commonly in use so if you're seeing SSL
version 3.0 requests on your network they're probably crappy old machine
somewhere old browsers or malicious traffic the longer it goes the more it's
lately as malicious traffic I'll tell you why I just say
the deprecated versions of TLS 1.0 1.1 are supported through the version 72
which is what we had was pretty much what's current now with us interchange
was it was just the release of some zero-day and Chronos with us coming that
numbers been chained verge from 81 and above for Chrome will not or any TLS
versions but two or three okay that's coming out sooner than the March 2020
date off of my cloud services optimize a content delivery network they only
support Denver suburbs by nineteen so they're ahead of curve all right
everything that they put out there anything that said Netflix uses them to
distribute their content it's only gonna be available via to us one point one one
with two or three PCI compliance deprecated tells them one one and our
data security standard on June 30th 2018 tell us 1.1 still allowed new compliance
tests to on your network there's only certain Cypress roots that are allowed
to be enabled on say how you check for this but most every every merchant has
switch to tell us one point two CloudFlare is disabled TLS 1.1 and one
more knowledgeable 18 so they're effectively act 1.2 level so a lot of
the provider level services have already changed Microsoft Office we should see
five on this of course TLS 1.2 starting over
18 there is no option windows where I talked about that to those who support
along three new Microsoft an apple and Mozilla does Firefox have agreed to an
TLS 1.1 what ones were partially in Marshall employment so right now they
currently say less than two percent of all traffic is to us one point one point
two that's not what we see on our network there there's no a lot more
machines and devices and things out there that are using these old versions
of old libraries problems how to get around getting those updated some of
them just will never be updated until is new points who are better is required
for HTTP 2.0 to be enabled on your network
I believe it's a strict requirement for TLS 1.3 so it's only kind of offer a
limited number of cipher suites so SSL labs estimates about 94% of all existing
sites or tell us 1.2 and it's a lie that's from our traffic that we've seen
what we have customers that are processing through that web filtering
service that we run we see a large number of people still tiny Frank
decided uses 1.0 as their standard connection we haven't turned that off
yet because we don't want customers flooding us with calls so bigger issues
going to be other services like SMTP IMAP and those sorts of things so the
thing that people are not thinking about in any great detail here are what is
Alliance implications is not having my TLS version so you're a large bank and
you will require to just to be compliant starving toxic so right box that says
well they don't allow you to do anything to tell us 1.2 and we're not that across
the board mobiles like just your website know that
applies to your email so if your did you email with anybody out there
world we want you to initiate connection only said by smtps and only the TLS 1.2
or better well how many people's mail server
support TLS 1.2 or better right everybody's mouth server that I have a
sense of trying to negotiate TLS have done or trust another person then
finally gives us the second clear well that's not compliant so they test you
for compliance you're going up there how do you fix that
that's outside of your control key not sending messages to people who have
email addresses on services that don't support the latest versions of TLS this
is a dilemma that has to be looked at ality fixed because what's gonna happen
is you're going to companies that are in these positions that have to be
compliant over a barrel because your customers don't care they just won't
even right can't go you have to be my customer you have to be like this mail
servers these are our fruit and mail services great it's kind of a big deal
api's or TLS is also have to be checked right how many providers in doing
content delivery networks for your phone apps suddenly these not your most
popular phone app that smaller providers don't have ability or don't have the
knowledge or they haven't bothered to build an infrastructure lead sources
latest version of the TLS and some that are absolute work on your phone because
the content delivery network won't send the data over the network so it's
there's a lot of the lemon here's what's going to be happening one of the things
you're going to hear about i lied to will this as a second mention of DNS and
the topics you're gonna see a lot of the information about DNS or TLS and
encrypted DNS which would be a packet sent over
essentially you can tunneled into a DNS server client and server tienes over
HTTP slow this correct much I don't go right by says DNS has to be late fax
right so illness or gun right with the perfect DNS our CloudFlare the fact that
you can start making a mess so that the traffic is sent in an encrypted tunnel
between your deanna requester a server and the only thing that's good for is to
make sure that nobody's spoofing your DNS or reading the DMS packets that are
going out don't learn about the answer privacy there's a whole lot of things
that people can find out from your DNS we're looking at privacy of DNS the
other issue that it's going to be a big deal order these IOT devices right a lot
of more built on Linux subsystems they use the open SSL libraries to do their
stuff how many of them are updated all regular basis right so what's going to
happen to all of those places that are out there in the world are trying to
negotiate back to their API is that there are companies that are providing
support for them and suddenly the providers that are doing cloud services
or even the internet providers willing to pass traffic that's tell us one more
moment or SSL 3 or TLS 1 all those places are essentially been conditioned
and won't be able to function right who's going up deeper who's going to
take care of that those problems and these are the kinds of problems that
people aren't thinking about looking at they're not considering the implications
it's changes in the standards it's really a few of these vulnerabilities
you're not going to explain what they are because mobility these are some of
the attacks that we're out there going back to score Utley one of the big ones
anybody remember SSL strip optimal in spite of that out you used to be able to
smooth people you'd run up I guess it you're on a Kali Linux box
pretend to do the Wi-Fi get you to join up you sign into Facebook every
directory GPS the man in the middle all your traffic
doesn't work anymore typically on those sites because most sites now use HSTs
which is HTTP HTTP strict Transport if you try to go to Facebook and they
look at the headers the first it requires of the TT TPS and second there
are a list of servers that are or a list of domains that are allowed within the
browser there's a simians where it goes with those so they are looked up and
they cannot be spoofed by a little attack so that's something that it's got
rid of those sorts of things all of these all of these different
vulnerabilities though have had implications of the changes if you got
max these uploaded timelines but that time today that to go into all that if
you look at the timeline of when these vulnerabilities came out some of them
are more critical or severe than others they led to direct changes in the
tls/ssl versions some of the big ones is trouble to remember or partly right so
that was a vulnerability OpenSSL library where somebody could get into a machine
or some packets of machine that was about overflowing memory and dump
information about the private key into that packet back to them and then let's
hit the private key is kind of game over right they could get in their machine do
all kinds of nasty stuff Pluto was a little bit of a different attack I was a
downgrade attack its vulnerability SSL 3.0 so this is main reason that you'll
see a lot of traffic trying to negotiate a connection at one level several sent
back that I supported the that change my mind I want to build a
different level though you know gotta accept that they'll keep negotiating
until they get to the lowest possible level what's happening there's people
are trying to use that downgrade capability to get back to lower levels
to exploit some of these vulnerabilities right so by fixing your TLS versions and
limiting what short machines or your endpoints will accept you eliminate all
those vulnerabilities from your network right by not addressing this you move
those vulnerabilities out there and some of them it's pretty severe and very well
documented on how to exploit but you see that there's all these different ones
that have come up and what other develop this topic out so you can get at it and
there's some links that we'll talk more about all the details on all of these
but basically every one of these attacks is is initiated typically it's either a
man-in-the-middle attack so the attacker intercept a connection of handshake
station and alters the handshake if they're trying to exfiltrate data from
that connection and then they're going to go and request something that's the
force the client server to renegotiate the connection until they can get it to
a level where they can basically sniff the traffic for a period of time and
then in the background they can crack the keys that were used to encrypt that
traffic into later deeper of the traffic and some of these the vulnerabilities
were so severe that they can crack the key in real time once they do that they
can just read the traffic assets coming across so things that you have to keep
in mind here is that the server accept that and respond to these downgrade
requests right so that's a bad thing you you want you as the owner of whatever
servers are going out there you want to dictate what versions of TLS you're
going to support you don't want to allow clients to request insecure versions the
other problem is a lot of the server setup to use weak or deprecated ciphers
so the cipher suite is the mathematical algorithm that's used to generate the
key that's used to encrypt traffic at the second property asymmetrical and if
you use flex words that are too weak they're more easily easily broken so the
trick is you have to keep up with standards I know this is a Sun not
something many people do I'm gonna show you some tools for how to deal with this
first we will look at how we monitor for this our network if you look at a TCP
packet that's coming in with the first handshake ago she Asian the second third
lights I believe is in that packet will tell you what version that this lower
right corner there comes with version numbers of TLS the protocol version
that's trying to negotiate from client or if you server back to the client so
you see that in the packet in both directions in a conversation in larger
what we do is we look at that payload lon and in our case we use that v load
balancers to terminate the traffic so you connect to our service that
terminates on the load balancer and then we forward the traffic to somewhere on
the background now we do not decrypt the traffic on the load balance it was a
difference this is something that people a little sign that it might be awful but
I think it's important to know many services terminate their traffic on load
balances whether it's AJ proxy at 500 pounds whatever the first will serve or
virtual interface that's on the front internet-facing
on the back side and those connect to an array of servers nodes through a pool of
servers on the backside well think about this would you rather have end-to-end
encryption where the data is encrypted all the way through the f5 load balancer
to the back-end server or do you want the f5 load balancer to be decrypting
the traffic to have that traffic open on our connections we have a little
balancer the backend server this is an important question it's not one that
many people look at this company client standards will get but it's a big
deal ok so this this means that if somebody compromises one of those
back-end servers anywhere on that network right just typically that
network would share the month of variety of different servers they can sent the
traffic on that can actually between the back end of the load balancer and the
front end public facing side of whatever web server that is that traffic's all
encrypted right username passwords anything it's all there right so if
you're setting up your network you definitely want any encryption if you
can do it I know it's cool to be able to do all of your certificates and
everything else although battle terms pain-in-the-butt
have to manage more servers but the security implications of doing SSL
offloading on the load balancer are pretty severe if you don't want to do it
I think that beyond that this is part of an iris isn't Eve
we're using but f5 the balance which use TCL just told control language to
basically allow you to manipulate traffic on an interface before and after
it crosses on that interface so all we do here it's hard to see but if you get
busy I slice it downloaded all are going we're collecting bits out of the to see
beacon actually were looking at the second third bit or matching it to a
number or saying if that number is less than this number which means it's TLS 3
or 1.0 or less we drop the traffic right
what we do log it so what we did is I set up a bit of a Greylock clustered
grill up okay so you know who knows what's pointless I'm sorry venomous
plunked is they're going to know what a lot hibernation is send your logs for
many slights the ones all integrate have an interface where you can access search
do dashboard that sort of thing so gray line is like swamp it's a blog
aggregation sender lives there that's an elastic search database and it
has a specific format that it expects the data to come in it expects the data
to come in something called guilt or love extended lock format so that this
part here of the part that says where it sends out these if that long string
that's just a JSON back into get sensitive a lot of observer but this
allows us to go and do some really cool things along these on all of our
connections are track using idols we track client connection and the server
connections right to remember the handshake process
client connection server brings the connection that they should match I'll
show you what happens on the hill we set the decimal value to low susceptible to
in our case for dropping 3.9 unless we will change that shortly all the
connections are blocked very loud server we don't have an SSL termination on our
load balancers of this is all layer 4 transport or letter traffic we're not
looking at the data at the application layer so keep that mod you can tamil at
the transport layer but birth until us to be used in your data drivers to see
as we drop the connections are less than 1.0 and you still see a significant
number of people trying to connect to us which is interesting
so this graph here this is our dashboard that we use basically what it shows
something you have a bigger screen the top part is all of the tls/ssl
connections that we drop so they're all the ones that are trying to connect the
three point out we don't drop one point okay TLS won't point out all of the
connections on the on this top of its first big number there the one 91,000
that's the client connections so the client connection should pretty much
match the server pensions back right so when those two numbers are not fairly
cool and they're not pretty what's 11,000 difference so what do you
think that traffic is that's the 11000 difference they're all machines trying
to do downgrade attacks on in services right so they may send analysis packets
right now we're taking them but when we turn off 1.0 those numbers when we go
back to much more people of excludable 3.0 as the SSL Bertels so that's it's an
indication of what's happening on our network we use it because we can
actually tell what clients IP addresses are sending what type of requests to us
so we can go back to the VIP the source IP of the request we go to a client's
home you know you have devices on your net
sending us SSL connections allow you to throw that let's dig into that a little
bit more right sometimes I find that there's things on their network that
they didn't know existed and this is only for a web proxy service so this
isn't everything that we do we could apply this to key mail we filter email
for 14 million email boxes so people over there traffic on the female side we
host about 400,000 chained boxes at the moment however what our sister company
six dozen they have as much I'm not I don't have much insight of what they did
was between we're just starting on the murderer so this is just an example of
how we can look at this data look at manipulate this data create different
dashboards we can alert from somebody's tiny to the or the max number of
connections the other thing we could do at the load balancer levels we could go
back and say how can we make them better we can go in and actually look at
Cypress weeks and the TCP connection in telling you what Cypress roots are
trying to negotiate as well there's other pieces of information in that act
that that you could look at who could break them at the number of TCP
connections trying to make connections to our SSL right to prevent the adolfs
attacks we can do key exchange validation on that to see what kinds of
keys with trying to validate on we can apply this to other types of interfaces
so to get this work basically you look balance of some wherever your endpoint
is you could do this on a server as well I suppose you write testing rule level
to do this production reply to the desire interface and
configure there's my blog blogging is going to be different on every type of
platform and there's other talks that I'm getting on how to configure a lot
there's a bunch of tools out there so we have a specific question feel free to
hit me up and I went in the right direction we do have a great lot of
custom that we use I guess or notes on the front end and the glass to search
muster on the back end really the only tools you need to test
to make sure this works requires RTC we don't want the load balancer and maybe
if you want to track down your own packaging into some escaping and
generate your own TCP packets with SSL encryption the civil world works
here's a whole time interesting links going over a couple more things you're
going to be pretty much about out of time so these links will be in the
slideshow one of the things I want to show you here is what you see when you
go to SSL test.com this is something but I might call us or you can actually go
and test the quality of the SSL or TLS or HTTPS we're on college install on
your different platforms I would recommend if your system admin and you
do this I don't have all the output your basis of this church or the websites
that we host in an experimental environment it's running TLS 1.3 that's
right on nginx parameters here and a couple of things to look at it does do
the desperate transport and it also does there's a record that you can put in
your DNS that will improve your TLS scores
multi-ball providers now expect you to create a specific text record in your
dns free domain and that tax record tells you which certificate authorities
were allowed to generate certificates for your link back this is important for
somebody to generate a certificate for your domain without your permission of
baby there's an email an email account for happened
the main generator city or some other domain or for your own though be neat
and smooth traffic to a sublimating for your domain is reducing a lot of
positivity this DNS will help sort that out for you
this is a separate text that does clients testing it for web selves and
this is the same website don't have to tell us when we applied to it now it
passed PCI compliance 100% agree there are four issues found for HIPAA
compliance and for furnace the only issues of were found on this site were
cipher suites that were enabled that have to be disabled at the state level
off the ticket when they get back to work if you go through this it gives you
a whole lot of detail on the things you need to address to make your SSL TLS
aerated connections be as good as they can be so the other thing you want to
look at on this is what we saw back to the SSL test site these are the ciphers
that were used that are available at tests every site for against your
platform and if these come up in red and those ciphers need to be removed from
your platform with a certain security it tells you the bid strength and it tells
you which cipher is which ones they're in the order that they prefer so you
always want to have it do the refer ciphers approach here's how I did this
on us CentOS on machine and web server I compiled an actual source code because
it was version was needed to do to TLS three two one
that persons needed for our TLS 1.3 as well I linked the diffie-hellman key to
keep around a fourth of at least 4096 bits and then put that into the
configuration a curve that it supports and then
there's the ciphers I can do to be more detailed Robinson to config for these I
don't care if you want to do this on your own but set these up test them or
need some help doing this with nginx you can do it with Apache as well there was
a bug do not absolutely well you can go there probably if you're running even
the latest version would probably patch to get up not I think so the one that's
not broken of a version that was broken that's why I pulled it out of here
because I couldn't do it to work with 1.3 if somebody if you're sharing
environment so they can upload a PHP script to get an account with various
persons get encounter server public PHP script run that script through their
website think you're doing is share hoster and they never read access
terrible is that big apache so check it out so we're out of time it's over but
if you have any questions you can reach me there
you